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Sample records for microstrip array antenna

  1. Wideband Microstrip Antenna-Feeding Array

    NASA Technical Reports Server (NTRS)

    Huang, John

    1990-01-01

    Special impedance-matching probes help reduce feed complexity. Lightweight array of microstrip antenna elements designed to transmit and illuminate reflector antenna with circularly polarized radiation at 1,545 to 1,550 MHz and to receive circularly polarized radiation at 1,646 to 1,660 MHz. Microstrip array is cluster of 7 subarrays containing total of 28 microstrip patches. Produces cicularly polarized beam with suitable edge taper to illuminate reflector antenna. Teardrop-shaped feed probe provides gradual change of field from coaxial transmission line into microstrip substrate. Intended to be part of larger overlapping-cluster array generating multiple contiguous beams.

  2. Design of microstrip disk antenna arrays

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.; Parks, F. G.

    1978-01-01

    The radio frequency characteristics and design parameters for microstrip disk antenna elements and planar arrays are presented. Two C-band model arrays (an 8 element linear and an 8 by 8 planar) were designed, fabricated, and tested to demonstrate the technique of using microstrip elements for array applications. These arrays were designed with a cosine amplitude distribution.

  3. Planar microstrip YAGI antenna array

    NASA Technical Reports Server (NTRS)

    Huang, John (Inventor)

    1993-01-01

    A directional microstrip antenna includes a driven patch surrounded by an isolated reflector and one or more coplanar directors, all separated from a ground plane on the order of 0.1 wavelength or less to provide end fire beam directivity without requiring power dividers or phase shifters. The antenna may be driven at a feed point a distance from the center of the driven patch in accordance with conventional microstrip antenna design practices for H-plane coupled or horizontally polarized signals. The feed point for E-plane coupled or vertically polarized signals is at a greater distance from the center than the first distance. This feed point is also used for one of the feed signals for circularly polarized signals. The phase shift between signals applied to feed points for circularly polarized signals must be greater than the conventionally required 90 degrees and depends upon the antenna configuration.

  4. Microstrip antenna arrays with parasitic elements

    NASA Technical Reports Server (NTRS)

    Lee, Kai-Fong

    1996-01-01

    This research was concerned with using parasitic elements to improve the bandwidth, gain and axial ratio characteristics of microstrip antennas and arrays. Significant improvements in these characteristics were obtained using stacked and coplanar parasitic elements. Details of the results are described in a total of 16 journal and 17 conference papers. These are listed in Section four of this report.

  5. Microstrip antenna array with parasitic elements

    NASA Technical Reports Server (NTRS)

    Lee, Kai F.; Acosta, Roberto J.; Lee, Richard Q.

    1987-01-01

    Discussed is the design of a large microstrip antenna array in terms of subarrays consisting of one fed patch and several parasitic patches. The potential advantages of this design are discussed. Theoretical radiation patterns of a subarray in the configuration of a cross are presented.

  6. Multilayer Microstrip Slot And Dipole Array Antenna

    NASA Technical Reports Server (NTRS)

    Tulintseff, Ann N.

    1994-01-01

    Multilayer antenna structure contains interleaved linear subarrays of microstrip dipole and slot radiating antenna elements to provide compact, dual-band antenna. Structure also contains associated microstrip transmission lines, plus high-power amplifiers for transmission and low-noise amplifiers for reception. Overall function is to transmit in horizontal polarization at frequency of 29.634 GHz and receive in vertical polarization at 19.914 GHz, in direction 44 degrees from broadside to antenna. Antenna structure is part of apparatus described in "Steerable K/Ka-band Antenna for Land-Mobile Satellite Applications," NPO-18772.

  7. Design and fabrication of microstrip antenna arrays

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A microstrip array project was conducted to demonstrate the feasibility of designing and fabricating simple, low cost, low sidelobe phased arrays with circular disk microstrip radiating elements. Design data were presented for microstrip elements and arrays including the effects of the protective covers, the mutual interaction between elements, and stripline feed network design. Low cost multilayer laminate fabrication techniques were also investigated. Utilizing this design data two C-band low sidelobe arrays were fabricated and tested: an eight-element linear and a sixty-four element planar array. These arrays incorporated stripline Butler matrix feed networks to produce a low sidelobe broadside beam.

  8. Microstrip Antenna Arrays on Multilayer LCP Substrates

    NASA Technical Reports Server (NTRS)

    Thompson, Dane; Bairavasubramanian, Ramanan; Wang, Guoan; Kingsley, Nickolas D.; Papapolymerou, Ioannis; Tenteris, Emmanouil M.; DeJean, Gerald; Li, RonglLin

    2007-01-01

    A research and development effort now underway is directed toward satisfying requirements for a new type of relatively inexpensive, lightweight, microwave antenna array and associated circuitry packaged in a thin, flexible sheet that can readily be mounted on a curved or flat rigid or semi-rigid surface. A representative package of this type consists of microwave antenna circuitry embedded in and/or on a multilayer liquid- crystal polymer (LCP) substrate. The circuitry typically includes an array of printed metal microstrip patch antenna elements and their feedlines on one or more of the LCP layer(s). The circuitry can also include such components as electrostatically actuated microelectromechanical systems (MEMS) switches for connecting and disconnecting antenna elements and feedlines. In addition, the circuitry can include switchable phase shifters described below. LCPs were chosen over other flexible substrate materials because they have properties that are especially attractive for high-performance microwave applications. These properties include low permittivity, low loss tangent, low water-absorption coefficient, and low cost. By means of heat treatments, their coefficients of thermal expansion can be tailored to make them more amenable to integration into packages that include other materials. The nature of the flexibility of LCPs is such that large LCP sheets containing antenna arrays can be rolled up, then later easily unrolled and deployed. Figure 1 depicts a prototype three- LCP-layer package containing two four-element, dual-polarization microstrip-patch arrays: one for a frequency of 14 GHz, the other for a frequency of 35 GHz. The 35-GHz patches are embedded on top surface of the middle [15-mil (approx.0.13-mm)-thick] LCP layer; the 14- GHz patches are placed on the top surface of the upper [9-mil (approx. 0.23-mm)-thick] LCP layer. The particular choice of LCP layer thicknesses was made on the basis of extensive analysis of the effects of the

  9. Method for calculating longitudinal microstrip antennas in planar phased arrays

    NASA Astrophysics Data System (ADS)

    Indenbom, M. V.

    The characteristics of longitudinal microstrip antennas in a planar phased array are examined on the basis of the application of the finite element method to an integral equation for the 'charge' on the microstrip line. Microstrip dipoles, and Yagi and log-periodic antennas are examples of such radiators. The analysis takes into account the complex configuration of the conductors, both current components, and the presence of dielectric substrates and a protective coating.

  10. Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2000-01-01

    The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss, radiation patterns and cross-polarization levels.

  11. Design of a Foldable Low-loss Microstrip Array Antenna

    NASA Technical Reports Server (NTRS)

    Christodoulou, C. G.; Wahid, P. F.; Haque, M. M.; Bailey, M. C.

    1999-01-01

    The design and analysis of a series-fed, foldable microstrip array antenna for radiometer applications is presented. The array antenna is composed of two equal sub arrays. Each sub array consists of a series of patches connected together through segments of microstrip lines. The sub arrays are fed 180 degree out of phase to ensure a symmetric radiation pattern. The design approach, is accomplished using the IE3D code that utilizes the method of moments. All experimental and simulated data are presented and discussed.

  12. Slotline fed microstrip antenna array modules

    NASA Technical Reports Server (NTRS)

    Lo, Y. T.; Oberhart, M. L.; Brenneman, J. S.; Aoyagi, P.; Moore, J.; Lee, R. Q. H.

    1988-01-01

    A feed network comprised of a combination of coplanar waveguide and slot transmission line is described for use in an array module of four microstrip elements. Examples of the module incorporating such networks are presented as well as experimentally obtained impedance and radiation characteristics.

  13. Microstrip Yagi array for MSAT vehicle antenna application

    NASA Technical Reports Server (NTRS)

    Huang, John; Densmore, Arthur; Pozar, David

    1990-01-01

    A microstrip Yagi array was developed for the MSAT system as a low-cost mechanically steered medium-gain vehicle antenna. Because its parasitic reflector and director patches are not connected to any of the RF power distributing circuit, while still contributing to achieve the MSAT required directional beam, the antenna becomes a very efficient radiating system. With the complete monopulse beamforming circuit etched on a thin stripline board, the planar microstrip Yagi array is capable of achieving a very low profile. A theoretical model using the Method of Moments was developed to facilitate the ease of design and understanding of this antenna.

  14. Microstrip patch antenna receiving array operating in the Ku band

    NASA Technical Reports Server (NTRS)

    Walcher, Douglas A.

    1996-01-01

    Microstrip patch antennas were first investigated from the idea that it would be highly advantageous to fabricate radiating elements (antennas) on the same dielectric substrate as RF circuitry and transmission lines. Other advantages were soon discovered to be its lightweight, low profile, conformability to shaped surfaces, and low manufacturing costs. Unfortunately, these same patches continually exhibit narrow bandwidths, wide beamwidths, and low antenna gain. This thesis will present the design and experimental results of a microstrip patch antenna receiving array operating in the Ku band. An antenna array will be designed in an attempt to improve its performance over a single patch. Most Ku band information signals are either wide band television images or narrow band data and voice channels. An attempt to improve the gain of the array by introducing parasitic patches on top of the array will also be presented in this thesis.

  15. A 32 GHz microstrip array antenna for microspacecraft application

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1994-01-01

    JPL/NASA is currently developing microspacecraft systems for future deep space applications. One of the frequency bands being investigated for microspacecraft is the Ka-band (32 GHz), which can be used with smaller equipment and provides a larger bandwidth. This article describes the successful development of a circularly polarized microstrip array with 28 dBic of gain at 32 GHz. This antenna, which is thin, flat, and small, can be surface-mounted onto the microspacecraft and, hence, takes very little volume and mass of the spacecraft. The challenges in developing this antenna are minimizing the microstrip antenna's insertion loss and maintaining a reasonable frequency bandwidth.

  16. Microstrip Yagi array antenna for mobile satellite vehicle application

    NASA Technical Reports Server (NTRS)

    Huang, John; Densmore, Arthur C.

    1991-01-01

    A novel antenna structure formed by combining the Yagi-Uda array concept and the microstrip radiator technique is discussed. This antenna, called the microstrip Yagi array, has been developed for the mobile satellite (MSAT) system as a low-profile, low-cost, and mechanically steered medium-gain land-vehicle antenna. With the antenna's active patches (driven elements) and parasitic patches (reflector and director elements) located on the same horizontal plane, the main beam of the array can be tilted, by the effect of mutual coupling, in the elevation direction providing optimal coverage for users in the continental United States. Because the parasitic patches are not connected to any of the lossy RF power distributing circuit the antenna is an efficient radiating system. With the complete monopulse beamforming and power distributing circuits etched on a single thin stripline board underneath the microstrip Yagi array, the overall L-band antenna system has achieved a very low profile for vehicle's rooftop mounting, as well as a low manufacturing cost. Experimental results demonstrate the performance of this antenna.

  17. A microstrip array feed for MSAT spacecraft reflector antenna

    NASA Technical Reports Server (NTRS)

    Huang, John

    1988-01-01

    An L-band circularly polarized microstrip array antenna with relatively wide bandwidth has been developed. The array has seven subarrays which form a single cluster as part of a large overlapping cluster reflector feed array. Each of the seven subarrays consists of four uniquely arranged linearly polarized microstrip elements. A 7.5 percent impedance (VSWR less than 1.5) as well as axial ratio (less than 1 dB) bandwidths have been achieved by employing a relatively thick honeycomb substrate with special impedance matching feed probes.

  18. The study of microstrip antenna arrays and related problems

    NASA Technical Reports Server (NTRS)

    Lo, Y. T.

    1984-01-01

    The physical layout of the array elements and the proximity of the microstrip feed network makes the input impedance and radiation pattern values dependent upon the effects of mutual coupling, feedline discontinuities and feed point location. The extent of these dependences was assessed and a number of single patch and module structures were constructed and measured at an operating frequency of approximately 4.0 GHz. The empirical results were compared with the ones which were theoretically predicted by the cavity model of thin microstrip antennas. Each element was modelled as an independent radiating patch and each microstrip feedline as an independent, quasi-TEM transmission line. The effects of the feedline discontinuities are approximated by lumped L-C circuit models.

  19. UHF Microstrip Antenna Array for Synthetic- Aperture Radar

    NASA Technical Reports Server (NTRS)

    Thomas, Robert F.; Huang, John

    2003-01-01

    An ultra-high-frequency microstrippatch antenna has been built for use in airborne synthetic-aperture radar (SAR). The antenna design satisfies requirements specific to the GeoSAR program, which is dedicated to the development of a terrain-mapping SAR system that can provide information on geology, seismicity, vegetation, and other terrain-related topics. One of the requirements is for ultra-wide-band performance: the antenna must be capable of operating with dual linear polarization in the frequency range of 350 plus or minus 80 MHz, with a peak gain of 10 dB at the middle frequency of 350 MHz and a gain of at least 8 dB at the upper and lower ends (270 and 430 MHz) of the band. Another requirement is compactness: the antenna must fit in the wingtip pod of a Gulfstream II airplane. The antenna includes a linear array of microstrip-patch radiating elements supported over square cavities. Each patch is square (except for small corner cuts) and has a small square hole at its center.

  20. A study of microstrip antenna elements and arrays

    NASA Astrophysics Data System (ADS)

    Lo, Y. T.; Richards, W. F.; Simon, P.

    1980-12-01

    Thin microstrip antennas have many unique and attractive properties, but their operation is much limited in bandwidth. In this report an attempt is made to develop a procedure for array design, in particular, to determine whether or not the band of operation could be broadened by using a small array of two elements of slightly different dimensions. By broadband, it is meant that the antenna must have over the bandwidth: (1) an input impedance variation within a certain prescribed SWR (say 3:1); (2) a stable pattern (in particular a stable beam-pointing direction); (3) a small variation in gain (or efficiency); and (4) in some applications, small variations in beamwidth and sidelobe level. In this work only the first two fundamental performances are considered. Insofar as the impedance is considered, the array design is essentially a circuit problem. Our theory, based on the cavity model, has previously shown that the element impedance can adequately be described by a Foster network representation, namely, a series circuit of infinitely many parallel resonant circuits, each corresponding to a mode of the cavity. For frequencies in the vicinity of a certain mode, the circuit can further be reduced to a single parallel resonant circuit of that mode in series with an inductance. Our earlier investigation has also shown that, except for very close spacings, the mutual coupling effect between elements can be ignored.

  1. Design of a low-loss series-fed microstrip array antenna

    NASA Technical Reports Server (NTRS)

    Mahbub, M. R.; Christodoulou. C. G.; Bailey, M. C.

    1998-01-01

    The design and analysis of a series-fed, low-loss, inverted microstrip array antenna, operating at 1.413 GHz is presented. The array antenna is composed of two sub arrays. Each sub array consists of an equal number of microstrip patches all connected together through a series microstrip line. The first element of each sub array is coaxially fed but 180 degree out of phase. This approach ensures a symmetric radiation pattern. The design approach, is accomplished using the IE3D code that utilizes the method of moments. All experimental and simulated data are presented and discussed.

  2. Microstrip antenna developments at JPL

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

    The in-house development of microstrip antennas, initiated in 1981, when a spaceborne lightweight and low-profile planar array was needed for a satellite communication system, is described. The work described covers the prediction of finite-ground-plane effects by the geometric theory of diffraction, higher-order-mode circularly polarized circular patch antennas, circularly polarized microstrip arrays with linearly polarized elements, an impedance-matching teardrop-shaped probe feed, a dual-polarized microstrip array with high isolation and low cross-polarization, a planar microstrip Yagi array, a microstrip reflectarray, a Ka-band MMIC array, and a series-fed linear arrays.

  3. Microstrip monpulse dipole array

    NASA Astrophysics Data System (ADS)

    Miccioli, W.; Toth, J.; Sa, N.; Lewis, M.

    1985-01-01

    The development of a microstrip radiating aperture utilizing multiple microstrip dipole radiators fed by a resonant feed configuration is described. This array combines an efficient capacitively coupled radiator feeding mechanism with a planar power divider configuration to achieve an extremely thin, lightweight antenna aperture. Linear array dipole matching theory and radiator bandwidth improvement techniques are also described. A quadrant based microstrip monopulse antenna was constructed. Experimental data from this array, its subassemblies and individual components are presented and compared to analytical predictions.

  4. The study of microstrip antenna arrays and related problems

    NASA Technical Reports Server (NTRS)

    Lo, Y. T.

    1986-01-01

    In February, an initial computer program to be used in analyzing the four-element array module was completed. This program performs the analysis of modules composed of four rectangular patches which are corporately fed by a microstrip line network terminated in four identical load impedances. Currently, a rigorous full-wave analysis of various types of microstrip line feed structures and patches is being performed. These tests include the microstrip line feed between layers of different electrical parameters. A method of moments was implemented for the case of a single dielectric layer and microstrip line fed rectangular patches in which the primary source is assumed to be a magnetic current ribbon across the line some distance from the patch. Measured values are compared with those computed by the program.

  5. Microstrip antenna theory and design

    NASA Astrophysics Data System (ADS)

    James, J. R.; Hall, P. S.; Wood, C.

    Microstrip is the name given to a type of open waveguiding structure which is now commonly used in present-day electronics, not only as a transmission line but for circuit components such as filters, couplers, and resonators. The idea of using microstrip to construct antennas is a much more recent development. The purpose of this monograph is to present the reader with an appreciation of useful antenna design approaches and the overall state-of-the art situation. Flat-plate antenna techniques and constraints on performance are considered along with microstrip design equations and data, the radiation mechanism of an open-circuit microstrip termination and the resulting design implications, the basic methods of calculation and design of patch antennas, and linear array techniques. Attention is also given to techniques and design limitations in two-dimensional arrays, circular polarization techniques, manufacturing and operational problems of microstrip antennas, recent advances in microstrip antenna analysis, and possible future developments.

  6. The design and fabrication of microstrip omnidirectional array antennas for aerospace applications

    NASA Technical Reports Server (NTRS)

    Campbell, T. G.; Appleton, M. W.; Lusby, T. K.

    1976-01-01

    A microstrip antenna design concept was developed that will provide quasi-omnidirectional radiation pattern characteristics about cylindrical and conical aerospace structures. L-band and S-band antenna arrays were designed, fabricated, and, in some cases, flight tested for rocket, satellite, and aircraft drone applications. Each type of array design is discussed along with a thermal cover design that was required for the sounding rocket applications.

  7. Microstrip Antennas with Polarization Diversity across a Wide Frequency Range and Phased Array Antennas for Radar and Satellite Communications

    NASA Astrophysics Data System (ADS)

    Ho, Kevin Ming-Jiang

    The thesis comprises of 3 projects; an L-band microstrip antenna with frequency agility and polarization diversity, X-band phased array antennas incorporating commercially packaged RFIC phased array chips, and studies for Ku/Ka-band shared aperture antenna array. The first project features the use of commercially packaged RF-MEMS SPDT switches, that boasts of high reliability, high linearity, low losses, hermetically packaged and fully compatible for SMTA processes for mass-assembly and production. Using the switches in a novel manner for the feed network, microstrip antennas with polarization diversity are presented. Frequency agility is achieved with the use of tuning diodes to provide capacitive loading to the antenna element. Additional inductance effects from surface-mounted capacitors, and its impact, is introduced. Theoretical cross-polarization of probe-fed antenna elements is presented for both linear and circular polarized microstrip antennas. Designs and measurements are presented, for microstrip antennas with polarization diversity, wide frequency tuning range, and both features. Replacement of the tuning diodes with commercially-packaged high Q RF MEMS tunable capacitors will allow for significant improvements to the radiation efficiency. In another project, multi-channel CMOS RFIC phased-array receiver chips are assembled in QFN packages and directly integrated on the same multi-layered PCB stack-up with the antenna arrays. Problems of isolation from the PCB-QFN interface, and potential performance degradation on antenna array from the use of commercial-grade laminates for assembly requirements, namely potential scan blindness and radiation efficiency, are presented. Causes for apparent drift of dielectric constant for microstrip circuits, and high conductor losses observed in measurements, are introduced. Finally, studies are performed for the design of a Ku/Ka-Band shared aperture array. Different approaches for developing dual-band shared apertures

  8. Microstrip Patch Antenna And Method

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W. (Inventor)

    2001-01-01

    Method and apparatus are provided for a microstrip feeder structure for supplying properly phased signals to each radiator element in a microstrip antenna array that may be utilized for radiating circularly polarized electromagnetic waves. In one disclosed embodiment. the microstrip feeder structure includes a plurality of microstrip sections many or all of which preferably have an electrical length substantially equal to one-quarter wavelength at the antenna operating frequency. The feeder structure provides a low loss feed structure that may be duplicated multiple times through a set of rotations and translations to provide a radiating array of the desired size.

  9. The study of microstrip antenna arrays and related problems

    NASA Technical Reports Server (NTRS)

    Lo, R. Q.

    1984-01-01

    The work on rectangular microstrip antennas for dual frequency operation is reported on. The principle of this approach is based on the excitation of a patch for two or more different modes which correspond to different frequencies. However, for a given geometry, the modal frequencies have a fixed relationship; therefore, the usefulness of such a design is greatly limited. In this study three different methods have been contrived to control the frequency ratio over a wide range. First, as found prevously, if shorting pins are inserted at certain locations in the patch, the low frequency can be raised substantially. Second, if slots are cut in the patch, the high frequency can be lowered considerably. By using both techniques, the two frequency ratio can be varied approximately from 3 to 1.3. After that, the addition of more pins or slots becomes ineffective.

  10. The 20 GHz circularly polarized, high temperature superconducting microstrip antenna array

    NASA Technical Reports Server (NTRS)

    Morrow, Jarrett D.; Williams, Jeffery T.; Long, Stuart A.; Wolfe, John C.

    1994-01-01

    The primary goal was to design and characterize a four-element, 20 GHz, circularly polarized microstrip patch antenna fabricated from YBa2Cu3O(x) superconductor. The purpose is to support a high temperature superconductivity flight communications experiment between the space shuttle orbiter and the ACTS satellite. This study is intended to provide information into the design, construction, and feasibility of a circularly polarized superconducting 20 GHz downlink or cross-link antenna. We have demonstrated that significant gain improvements can be realized by using superconducting materials for large corporate fed array antennas. In addition, we have shown that when constructed from superconducting materials, the efficiency, and therefore the gain, of microstrip patches increases if the substrate is not so thick that the dominant loss mechanism for the patch is radiation into the surface waves of the conductor-backed substrate. We have considered two design configurations for a superconducting 20 GHz four-element circularly polarized microstrip antenna array. The first is the Huang array that uses properly oriented and phased linearly polarized microstrip patch elements to realize a circularly polarized pattern. The second is a gap-coupled array of circularly polarized elements. In this study we determined that although the Huang array operates well on low dielectric constant substrates, its performance becomes extremely sensitive to mismatches, interelement coupling, and design imperfections for substrates with high dielectric constants. For the gap-coupled microstrip array, we were able to fabricate and test circularly polarized elements and four-element arrays on LaAlO3 using sputtered copper films. These antennas were found to perform well, with relatively good circular polarization. In addition, we realized a four-element YBa2Cu3O(x) array of the same design and measured its pattern and gain relative to a room temperature copper array. The patterns were

  11. Novel Compact Mushroom-Type EBG Structure for Electromagnetic Coupling Reduction of Microstrip Antenna array

    NASA Astrophysics Data System (ADS)

    Hu, Lizhong; Wang, Guangming; Liang, Jiangang; Zhang, Chenxin

    2015-03-01

    A novel compact electromagnetic bandgap (EBG) structure consisting of two turns complementary spiral resonator (CSR) and conventional mushroom EBG (CM-EBG) structure is introduced to suppress the mutual coupling in antenna arrays for multiple-input and multiple-output (MIMO) applications. Eigenmode calculation is used to investigate the proposed CSR-loaded mushroom-type EBG (MT-EBG), which proved to exhibit bandgap property and a miniaturization of 48.9% is realized compared with the CM-EBG. By inserting the proposed EBG structure between two E-plane coupled microstrip antennas, a mutual coupling reduction of 8.13 dB has been achieved numerically and experimentally. Moreover, the EBG-loaded antenna has better far-field radiation patterns compared with the reference antenna. Thus, this novel EBG structure with advantages of compactness and high decoupling efficiency opens an avenue to new types of antennas with super performances.

  12. Design and analysis of an electronically steerable microstrip patch and a novel Coplanar Waveguide (CPW) fed slot antenna array

    NASA Astrophysics Data System (ADS)

    Aldossary, Hamad

    Conformal Phased Array Antennas (CPAAs) are very attractive for their high gain, low profile, and beam scanning ability while being conformal to their mounting surface. Among them are microstrip patch phased arrays and wideband slot phased arrays which are of particular significance. In this work, first the study, design, and implementation of a conformal microstrip patch phased array is presented which consists of a high gain beam scanning array implemented using microstrip delay lines controlled using GaAs SPDT switches. Then the study and design of a wideband Coplanar Waveguide (CPW)-fed slot phased array antenna is presented. In both cases the array beam scanning properties are elucidated by incorporating the measured delay line scattering parameters inside Ansys Designer simulation models and then computing and presenting their full-wave radiation characteristics.

  13. Aperture-coupled thin-membrane microstrip array antenna for beam scanning application

    NASA Technical Reports Server (NTRS)

    Huang, John; Sadowy, Gregory; Derksen, Chuck; Del Castillo, Linda; Smith, Phil; Hoffman, Jim; Hatake, Toshiro; Moussessian, Alina

    2005-01-01

    A microstrip array using aperture-slot-coupling technique with very thin membranes has been developed at the L-band frequency for beam scanning application. This technology-demonstration array with 4 x 2 elements achieved a relatively wide bandwidth of 100 MHz (8%) and +/-45(deg) beam scan. Very narrow coupling slots were used with each having an aspect ratio of 160 (conventional slot aspect ratio is between 10 to 30) for coupling through very thin membrane (0.05mm thickness). This thin-membrane aperture-coupling technique allows the array antenna elements to be more easily integrated with transmit/receive amplifier (T/R) and phase shifter modules. This paper addresses only the radiator portion of the array. The array and active components will be presented in a separate pape.

  14. Dual frequency, dual polarized, multi-layered microstrip slot and dipole array antenna

    NASA Technical Reports Server (NTRS)

    Tulintseff, Ann N. (Inventor)

    1995-01-01

    An antenna array system is disclosed which uses subarrays of slots and subarrays of dipoles on separate planes. The slots and dipoles respectively are interleaved, which is to say there is minimal overlap between them. Each subarray includes a microstrip transmission line and a plurality of elements extending perpendicular thereto. The dipoles form the transmission elements and the slots form the receive elements. The plane in which the slots are formed also forms a ground plane for the dipoles--hence the feed to the dipole is on the opposite side of this ground plane as the feed to the slots. HPAs are located adjacent the dipoles on one side of the substrate and LNAs are located adjacent the slots on the other side of the substrate. The dipoles and slots are tuned by setting different offsets between each element and the microstrip transmission line.

  15. Microstrip antenna technology

    NASA Astrophysics Data System (ADS)

    Carver, K. R.; Mink, J. W.

    1981-01-01

    A survey of microstrip antenna elements is presented, with emphasis on theoretical and practical design techniques. Available substrate materials are reviewed along with the relation between dielectric constant tolerance and resonant frequency of microstrip patches. Several theoretical analysis techniques are summarized, including transmission-line and modal-expansion (cavity) techniques as well as numerical methods such as the method of moments and finite-element techniques. Practical procedures are given for both standard rectangular and circular patches, as well as variations on those designs including circularly polarized microstrip patches. The quality, bandwidth, and efficiency factors of typical patch designs are discussed. Microstrip dipole and conformal antennas are summarized. Finally, critical needs for further research and development for this antenna are identified.

  16. Cavity-backed, micro-strip dipole antenna array

    NASA Astrophysics Data System (ADS)

    Ellis, H., Jr.

    1981-09-01

    A flush-mounted antenna assembly includes a generally rectangular, conductive, box structure open along one face to form a cavity. Within the cavity a pair of mutually orthogonal dielectric plane surfaces in an "egg crate" arrangement are mounted normal to the plane of the open face, each diagonally within the cavity. Each dielectric plane supports a pair of printed circuit dipoles typically each fed from the opposite side of the dielectric plane by a printed "cone-shaped" feed line trace which also serve as an impedance matching device and functions as a balun connected from an unbalanced strip line external feed. The open face of the conductive cavity can be flush mounted with a randome thereover, the assembly thereby being flush with the skin of a aircraft or space vehicle.

  17. Cavity-backed, micro-strip dipole antenna array

    NASA Technical Reports Server (NTRS)

    Ellis, H., Jr. (Inventor)

    1981-01-01

    A flush-mounted antenna assembly includes a generally rectangular, conductive, box structure open along one face to form a cavity. Within the cavity a pair of mutually orthogonal dielectric plane surfaces in an "egg crate" arrangement are mounted normal to the plane of the open face, each diagonally within the cavity. Each dielectric plane supports a pair of printed circuit dipoles typically each fed from the opposite side of the dielectric plane by a printed "cone-shaped" feed line trace which also serve as an impedance matching device and functions as a balun connected from an unbalanced strip line external feed. The open face of the conductive cavity can be flush mounted with a randome thereover, the assembly thereby being flush with the skin of a aircraft or space vehicle.

  18. The design of a microstrip antenna array for a UHF space telemetry link

    NASA Technical Reports Server (NTRS)

    Post, R. E.; Stephenson, D. T.

    1981-01-01

    An array of microstrip antenna panels was designed for use on a small instrumented satellite as part of a 400-MHz telemetry link between that satellite and NASA's shuttle spacecraft. A roughly omnidirectional phi-plane pattern was desired. The 1.4-wavelength diameter of the satellite and the various ports and structures on its surface presented strong constraints on the antenna array design. Eight antennas, each one a quarter-wavelength panel with one radiating and one shorted edge, were chosen. A phi-plane pattern ripple of 4.4 dB and a gain of at least 0.1 dB relative to a half-wavelength dipole were realized. The design technique used for the individual antenna panels included the study of feed-point location for impedance matching and the effect of losses in the dielectric. A superposition method was used to synthesize the radiation patterns for different numbers and different excitations of antennas on the satellite.

  19. Understanding and optimizing microstrip patch antenna cross polarization radiation on element level for demanding phased array antennas in weather radar applications

    NASA Astrophysics Data System (ADS)

    Vollbracht, D.

    2015-11-01

    The antenna cross polarization suppression (CPS) is of significant importance for the accurate calculation of polarimetric weather radar moments. State-of-the-art reflector antennas fulfill these requirements, but phased array antennas are changing their CPS during the main beam shift, off-broadside direction. Since the cross polarization (x-pol) of the array pattern is affected by the x-pol element factor, the single antenna element should be designed for maximum CPS, not only at broadside, but also for the complete angular electronic scan (e-scan) range of the phased array antenna main beam positions. Different methods for reducing the x-pol radiation from microstrip patch antenna elements, available from literature sources, are discussed and summarized. The potential x-pol sources from probe fed microstrip patch antennas are investigated. Due to the lack of literature references, circular and square shaped X-Band radiators are compared in their x-pol performance and the microstrip patch antenna size variation was analyzed for improved x-pol pattern. Furthermore, the most promising technique for the reduction of x-pol radiation, namely "differential feeding with two RF signals 180° out of phase", is compared to single fed patch antennas and thoroughly investigated for phased array applications with simulation results from CST MICROWAVE STUDIO (CST MWS). A new explanation for the excellent port isolation of dual linear polarized and differential fed patch antennas is given graphically. The antenna radiation pattern from single fed and differential fed microstrip patch antennas are analyzed and the shapes of the x-pol patterns are discussed with the well-known cavity model. Moreover, two new visual based electromagnetic approaches for the explanation of the x-pol generation will be given: the field line approach and the surface current distribution approach provide new insight in understanding the generation of x-pol component in microstrip patch antenna radiation

  20. Near- and Far-Field Characterization of Planar mm-Wave Antenna Arrays with Waveguide-to-Microstrip Transition

    NASA Astrophysics Data System (ADS)

    Salhi, Mohammed Adnan; Kazemipour, Alireza; Gentille, Gennaro; Spirito, Marco; Kleine-Ostmann, Thomas; Schrader, Thorsten

    2016-04-01

    We present the design and characterization of planar mm-wave patch antenna arrays with waveguide-to-microstrip transition using both near- and far-field methods. The arrays were designed for metrological assessment of error sources in antenna measurement. One antenna was designed for the automotive radar frequency range at 77 GHz, while another was designed for the frequency of 94 GHz, which is used, e.g., for imaging radar applications. In addition to the antennas, a simple transition from rectangular waveguide WR-10 to planar microstrip line on Rogers 3003™ substrate has been designed based on probe coupling. For determination of the far-field radiation pattern of the antennas, we compare results from two different measurement methods to simulations. Both a far-field antenna measurement system and a planar near-field scanner with near-to-far-field transformation were used to determine the antenna diagrams. The fabricated antennas achieve a good matching and a good agreement between measured and simulated antenna diagrams. The results also show that the far-field scanner achieves more accurate measurement results with regard to simulations than the near-field scanner. The far-field antenna scanning system is built for metrological assessment and antenna calibration. The antennas are the first which were designed to be tested with the measurement system.

  1. Near- and Far-Field Characterization of Planar mm-Wave Antenna Arrays with Waveguide-to-Microstrip Transition

    NASA Astrophysics Data System (ADS)

    Salhi, Mohammed Adnan; Kazemipour, Alireza; Gentille, Gennaro; Spirito, Marco; Kleine-Ostmann, Thomas; Schrader, Thorsten

    2016-09-01

    We present the design and characterization of planar mm-wave patch antenna arrays with waveguide-to-microstrip transition using both near- and far-field methods. The arrays were designed for metrological assessment of error sources in antenna measurement. One antenna was designed for the automotive radar frequency range at 77 GHz, while another was designed for the frequency of 94 GHz, which is used, e.g., for imaging radar applications. In addition to the antennas, a simple transition from rectangular waveguide WR-10 to planar microstrip line on Rogers 3003™ substrate has been designed based on probe coupling. For determination of the far-field radiation pattern of the antennas, we compare results from two different measurement methods to simulations. Both a far-field antenna measurement system and a planar near-field scanner with near-to-far-field transformation were used to determine the antenna diagrams. The fabricated antennas achieve a good matching and a good agreement between measured and simulated antenna diagrams. The results also show that the far-field scanner achieves more accurate measurement results with regard to simulations than the near-field scanner. The far-field antenna scanning system is built for metrological assessment and antenna calibration. The antennas are the first which were designed to be tested with the measurement system.

  2. The design and analysis of a phased array microstrip antenna for a low earth orbit communication satellite

    NASA Astrophysics Data System (ADS)

    Barfield, William L.

    1994-06-01

    A Naval Postgraduate School spacecraft design class proposed a multiple beam, phased array, microstrip antenna as part of the preliminary design of a low earth orbit communication satellite. The antenna must provide coverage over the satellite's entire field of view while both uplink and down-link operate simultaneously on the same 1-band frequency. This thesis assesses the feasibility of the antenna proposed in that preliminary design. Design tradeoffs for a microstrip array constrained by both available surface area and a limited mass budget are examined. Two different substrate materials are considered in terms of weight and performance. Microstrip patch theory is applied to array element design and layout and antenna array theory is applied to determine phase and amplitude coefficients. The focus of the design is on obtaining the desired beam shape and orientation, given antenna size constraints. A corporate feed method is discussed and a general design presented. Antenna performance is predicted through the use of a computer model based on Modal Expansion theory and results are plotted in a series of graphs which demonstrate the limitations of the proposed design.

  3. Handbook of microstrip antennas. Volumes 1 & 2

    NASA Astrophysics Data System (ADS)

    James, Jim R.; Hall, Peter S.

    The design and operation of microstrip antennas (MAs) are discussed in chapters contributed by leading experts. Topics addressed include the analysis of circular MAs, improving the frequency agility and bandwidth of patch MAs, circular polarization and bandwidth, microstrip dipoles, multilayer and parasitic MAs, wideband flat dipole and short-circuit MA patch elements and arrays, numerical analysis methods for MAs, multiport-network and transmission-line models of MAs, the design of low-cost printed MAs, printed phase-array antennas, and circularly polarized arrays. Consideration is given to MA feeds, substrate technology, measurement techniques for printed antennas, CAD of microstrip and triplate circuits, resonant MA elements and arrays for aerospace applications, MAs for mobile and satellite systems, a conical conformal microstrip tracking antenna, MA field diagnostics, MAs on a cylindrical surface, and extensions and variations of the MA concept.

  4. Circularly-Polarized Microstrip Antenna

    NASA Technical Reports Server (NTRS)

    Stanton, P. H.

    1985-01-01

    Microstrip construction compact for mobile applications. Circularly polarized microstrip antenna made of concentric cylindrical layers of conductive and dielectric materials. Coaxial cable feedlines connected to horizontal and vertical subelements from inside. Vertical subelement acts as ground for horizontal subelement.

  5. Investigation of broadband microstrip antenna structures for application in monolithic millimeter wave arrays

    NASA Astrophysics Data System (ADS)

    Chang, David C.; Kuester, E. F.

    1989-10-01

    The development of several ways of accurately yet efficiently modeled behavior of closely spaced microstrip antenna elements is shown. The accuracy was verified by comparison with brute force numerical procedures, and thus suggests that wideband microstrip antennas should be designable with much less difficulty than previously believed. Further, both experimental and numerical evidence was obtained for the proposition that wider bandwidth, and even lower frequency operation of a microstrip patch antenna element can be achieved by arranging many closely coupled narrow strip dipoles together in an appropriate way. An understanding of these effects is not completed; especially since there was no study of the frequency dependence of the radiation properties of these new elements. Design and optimization is also in a very primitive stage, as accurate modeling of their properties requires numerically intensive methods at this time. Questions of this nature deserve more investigation.

  6. Analysis of rectangular microstrip antennas

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.; Deshpande, M. D.

    1984-01-01

    The problem of microstrip antennas covered by a dielectric substrate is formulated in terms of coupled integro-differential equations with the current distribution on the conducting patch as an unknown quantity. The Galerkin method is used to solve for the unknown patch current. Using the present formulation, the radiation pattern, the resonant frequency, and the bandwidth of a rectangular microstrip antenna are computed. Design data for a rectangular microstrip antenna are also presented.

  7. A compact cylindrical-shape microstrip structure with cloaking properties for mutual coupling reduction in array antennas

    NASA Astrophysics Data System (ADS)

    Naqvi, Syed Aftab

    A cylindrical-shaped microstrip structure with cloaking properties is presented as a shielding device to reduce the mutual coupling between two patch antennas. The surface comprises of a number of 2-port microstrip (2-PM) elements printed on individual substrates and, to enclose a particular region, several 2-PM elements are interconnected into a cylindrical shape. Each 2-PM element has the capability of coupling an incident EM field on the surface to the adjacent interconnected elements. Then, because the 2-PM elements are connected into a cylindrical shape, the incident EM field is re-radiated from the other interconnected 2-PM elements in a direction away from the transmitter; achieving a behavior similar to a cloak. The prototypes in this dissertation illustrates that this surface has the additional benefit of overcoming many of the manufacturing difficulties of traditional cloaks because microstrip structures are used. To demonstrate this concept, a cylindrical surface operating at 3.89 GHz and a frequency reconfigurable surface (consisting of 2-port frequency reconfigurable microstrip elements (2-PFRM)) operating at 3.68 GHz and 3.89 GHz is simulated in HFSS, manufactured and measured in a full anechoic chamber. Moreover, as an application, the cylindrical surface operating at 3.89 GHz is used to reduce the mutual coupling between two patch antennas operating simultaneously at 3.89 GHz. The radiation pattern and the gain of a 2-element array is measured to demonstrate the negligible effects of a cylindrical surface on the far field antenna array parameters. Simulation and measurement results are in good agreement and validate the proposed EM cloak-based surface for applications such as antenna array shielding, radar cross section and communications in complex EM environments.

  8. Omnidirectional, circularly polarized, cylindrical microstrip antenna

    NASA Technical Reports Server (NTRS)

    Stanton, Philip H. (Inventor)

    1985-01-01

    A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a wraparound microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90.degree. from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

  9. A hybrid finite element method for scattering and radiation by microstrip patch antennas and arrays residing in a cavity

    NASA Astrophysics Data System (ADS)

    Jin, Jian-Ming; Volakis, John L.

    1991-11-01

    A hybrid numerical technique is presented for a characterization of the scattering and radiation properties of microstrip patch antennas and arrays residing in a cavity recessed in a ground plane. The technique combines the finite-element and boundary integral methods to formulate a system for the solution of the fields at the aperture and those inside the cavity via the biconjugate gradient method in conjunction with the fast Fourier transform (FFT). By virtue of the finite-element method, the proposed technique is applicable to patch antennas and arrays residing on or embedded in a layered dielectric substrate and is also capable of treating various feed configurations and impedance loads. Several numerical results are presented, demonstrating the validity, efficiency, and capability of the technique.

  10. A Polarization Reconfigurable Aperture-Coupled Microstrip Antenna and Its Binary Array for MIMO

    NASA Astrophysics Data System (ADS)

    Zhong, Lei; Hong, Jin-Song; Zhou, Hong-Cheng

    2016-03-01

    In the paper, a singly fed circular patch antenna with polarization diversity is proposed, and its binary array for MIMO application is explored as well. The air substrate and aperture-coupled feed structure are adopted to increase bandwidth and simplify the bias circuit of PIN diodes. By controlling the states of four PIN diodes on the patch, the proposed antenna can produce linear polarization (LP), left- or right-hand circular polarization (LHCP or RHCP). For each polarization sense, the antenna exhibits wide impedance bandwidth, high gain and low cross-polarization. Two antennas are orthogonally placed to form a binary array for MIMO application, which has high isolation and low envelope correlation. The antenna and its array have advantages of simple biasing network, easy fabrication and adjustment, which can be widely applied in wireless communication systems.

  11. Designing Rectangular RHCP Microstrip Antennas

    NASA Technical Reports Server (NTRS)

    Davidson, Shayla E.

    1987-01-01

    RHCP, Right-Handed, Circularly Polarized Microstrip Antenna program, aids in design of rectangular microstrip-antenna element, given desired frequency of operation and characteristics of substrate. Begins design calculations on basis of square element with linear polarization. Effective dielectric constant and changes in electrical length due to fringing at edges of radiating element taken into account. Coaxial feed inset with 50 ohms input impedance. Placement of feed such that two orthonormal modes produced in antenna cavity, right- or left-handed circular polarization obtained. Written in FORTRAN 77.

  12. Microstrip patch array antenna on photonic crystal substrate at terahertz frequency

    NASA Astrophysics Data System (ADS)

    Jha, Kumud Ranjan; Singh, G.

    2012-01-01

    Recent advancement in the fabrication and packaging technology has led to the micrometer and nanometer-scale device modeling. This technological development and subsequent reduction in the dimension of devices like modulators, detectors and antennas has brought a thought of increasing the operating frequency of the system to the extent of sub-millimeter wavelength. In the view of the technical breakthrough in the area of fabrication and packaging, we have explored a printed antenna array on the photonic crystal in the terahertz spectrum in this paper. An equivalent circuit model of the antenna has been proposed and a methodology to investigate various electrical parameters is discussed. Tunable parameters of the structure have been explored to optimize the electrical performance of the proposed antenna. The analysis is also compared by using two simulators: (a) CST Microwave Studio based on finite integral technique and (b) Ansoft HFSS based on finite element method. The effect of the photonic crystal as substrate to enhance the gain of this kind of the antenna has also been demonstrated. The gain, directivity, front-to-back ratio (F/B ratio), and the radiation efficiency of the proposed antenna at 600 GHz is 16.88 dBi, 17.19 dBi, 14.77 dB and 89.72%, respectively. Finally, the performance of the antenna has been compared with the reported literature.

  13. Spiral Microstrip Antenna with Resistance

    NASA Technical Reports Server (NTRS)

    Shively, David G. (Inventor)

    1998-01-01

    A spiral microstrip antenna having resistor elements embedded in each of the spiral arms is provided. The antenna is constructed using a conductive back plane as a base. The back plane supports a dielectric slab having a thickness between one-sixteenth and one-quarter of an inch. A square spiral, having either two or four arms, is attached to the dielectric slab. Each arm of the spiral has resistor elements thereby dissipating an excess energy not already emitted through radiation. The entire configuration provides a thin, flat, high gain, wide bandwidth antenna which requires no underlying cavity. The configuration allows the antenna to be mounted conformably on an aircraft surface.

  14. Ultra-small single-negative electric metamaterials for electromagnetic coupling reduction of microstrip antenna array.

    PubMed

    Xu, He-Xiu; Wang, Guang-Ming; Qi, Mei-Qing; Zeng, Hui-Yong

    2012-09-24

    We report initially the design, fabrication and measurement of using waveguided electric metamaterials (MTM) in the design of closely-spaced microtrip antenna arrays with mutual coupling reduction. The complementary spiral ring resonators (CSRs) which exhibit single negative resonant permittivity around 3.5GHz are used as the basic electric MTM element. For verification, two CSRs with two and three concentric rings are considered, respectively. By properly arranging these well engineered waveguided MTMs between two H-plane coupled patch antennas, both numerical and measured results indicate that more than 8.4 dB mutual coupling reduction is obtained. The mechanism has been studied from a physical insight. The electric MTM element is electrically small, enabling the resultant antenna array to exhibit a small separation (λo/8 at the operating wavelength) and thus a high directivity. The proposed strategy opens an avenue to new types of antenna with super performances and can be generalized for other electric resonators. PMID:23037347

  15. Characterization of bone tissue using microstrip antennas.

    PubMed

    Barros, Jannayna D; de Oliveira, Jose Josemar; da Silva, Sandro G

    2010-01-01

    The use of electromagnetic waves in the characterization of biological tissues has been conducted since the nineteenth century after the confirmation that electric and magnetic fields can interact with biological materials. In this paper, electromagnetic waves are used to characterize tissues with different levels of bone mass. In this way, one antenna array on microstrip lines was used. It can be seen that bones with different mass has different behavior in microwave frequencies. PMID:21097274

  16. A general approach of the active concept of microstrip antennas and arrays based on the loaded scatterer theory

    NASA Astrophysics Data System (ADS)

    Gillard, Raphael; Legay, Herve; Floch, Jean-Marie; Citerne, Jacques

    1991-06-01

    A quantitative and general approach of the active antenna concept concretized in planar type microstrip technologies is proposed using integral equation techniques associated with the multiport representation of loaded scatterers. Two configurations based on this concept, involving an electromagnetically fed microstrip dipole combined with either passive loads simulating a monolithic switch or active loads simulating a monolithic amplifier, are computed to illustrate the extended capacities of this new approach. Theoretical results on matching characteristics are compared to measurements achieved in X band.

  17. Microstrip Yagi Antenna with Dual Aperture-Coupled Feed

    NASA Technical Reports Server (NTRS)

    Pogorzelski, Ronald; Venkatesan, Jaikrishna

    2008-01-01

    A proposed microstrip Yagi antenna would operate at a frequency of 8.4 GHz (which is in the X band) and would feature a mechanically simpler, more elegant design, relative to a prior L-band microstrip Yagi antenna. In general, the purpose of designing a microstrip Yagi antenna is to combine features of a Yagi antenna with those of a microstrip patch to obtain an antenna that can be manufactured at low cost, has a low profile, and radiates a directive beam that, as plotted on an elevation plane perpendicular to the antenna plane, appears tilted away from the broadside. Such antennas are suitable for flush mounting on surfaces of diverse objects, including spacecraft, aircraft, land vehicles, and computers. Stated somewhat more precisely, what has been proposed is a microstrip antenna comprising an array of three Yagi elements. Each element would include four microstrip-patch Yagi subelements: one reflector patch, one driven patch, and two director patches. To obtain circular polarization, each driven patch would be fed by use of a dual offset aperture-coupled feed featuring bow-tie-shaped apertures. The selection of the dual offset bow-tie aperture geometry is supported by results found in published literature that show that this geometry would enable matching of the impedances of the driven patches to the 50-Omega impedance of the microstrip feedline while maintaining a desirably large front-to-back lobe ratio.

  18. Analysis of a microstrip reflectarray antenna for microspacecraft applications

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1995-01-01

    A microstrip reflectarray is a flat reflector antenna that can be mounted conformally onto a spacecraft's outside structure without consuming a significant amount of spacecraft volume and mass. For large apertures (2 m or larger), the antenna's reflecting surface, being flat, can be more easily and reliably deployed than a curved parabolic reflector. This article presents the study results on a microstrip reflect-array with circular polarization. Its efficiency and bandwidth characteristics are analyzed. Numerous advantages of this antenna system are discussed. Three new concepts using this microstrip reflectarray are also proposed.

  19. Theory and experiment for infinite microstrip arrays

    NASA Astrophysics Data System (ADS)

    Wright, S. M.; Lo, Y. T.

    1985-01-01

    Microstrip antennas are well suited for use in large scanning arrays. To obtain greater bandwidth, it is useful to use thicker substrates, which can increase the effects of mutual coupling and lead to significant mismatch or blindness for certain scan angles. Using an infinite array formulation, the impedance of a single element in an infinite array environment was solved with the method of moments. Mutual coupling is built into the solution, and the presence of surface waves is accounted for by using the periodic Green's function for the grounded dielectric substrate. Blindness in arrays of microstrip dipoles on various substrates, both with and without radomes is demonstrated.

  20. Design of 4x1 microstrip patch antenna array for 5.8 GHz ISM band applications

    NASA Astrophysics Data System (ADS)

    Valjibhai, Gohil Jayesh; Bhatia, Deepak

    2013-01-01

    This paper describes the new design of four element antenna array using corporate feed technique. The proposed antenna array is developed on the Rogers 5880 dielectric material. The antenna array works on 5.8 GHz ISM band. The industrial, scientific and medical (ISM) radio bands are radio bands (portions of the radio spectrum) reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than communications. The array antennas have VSWR < 1.6 from 5.725 - 5.875 GHz. The simulated return loss characteristic of the antenna array is - 39.3 dB at 5.8 GHz. The gain of the antenna array is 12.3 dB achieved. The directivity of the broadside radiation pattern is 12.7 dBi at the 5.8 GHz operating frequency. The antenna array is simulated using High frequency structure simulation software.

  1. High Performance Circularly Polarized Microstrip Antenna

    NASA Technical Reports Server (NTRS)

    Bondyopadhyay, Probir K. (Inventor)

    1997-01-01

    A microstrip antenna for radiating circularly polarized electromagnetic waves comprising a cluster array of at least four microstrip radiator elements, each of which is provided with dual orthogonal coplanar feeds in phase quadrature relation achieved by connection to an asymmetric T-junction power divider impedance notched at resonance. The dual fed circularly polarized reference element is positioned with its axis at a 45 deg angle with respect to the unit cell axis. The other three dual fed elements in the unit cell are positioned and fed with a coplanar feed structure with sequential rotation and phasing to enhance the axial ratio and impedance matching performance over a wide bandwidth. The centers of the radiator elements are disposed at the corners of a square with each side of a length d in the range of 0.7 to 0.9 times the free space wavelength of the antenna radiation and the radiator elements reside in a square unit cell area of sides equal to 2d and thereby permit the array to be used as a phased array antenna for electronic scanning and is realizable in a high temperature superconducting thin film material for high efficiency.

  2. Improved Dual-Polarized Microstrip Antenna

    NASA Technical Reports Server (NTRS)

    Huang, John

    1993-01-01

    Dual-polarized microstrip antenna features microstrip transmission-line feeds arranged in such configuration that cross-polarized components of radiation relatively low and degree of isolation between feed ports relatively high. V and H feed ports offset from midpoints of feed lines to obtain required opposite phases at feed-point connections to microstrip patches. Two independent beams of same frequency with electric fields polarized orthogonally to each other transmitted or received via antenna. Improved design saves space.

  3. A Microstrip Reflect Array Using Crossed Dipoles

    NASA Technical Reports Server (NTRS)

    Pozar, David M.; Targonski, Stephen D.

    1998-01-01

    Microstrip reflect arrays offer a flat profile and light weight, combined with many of the electrical characteristics of reflector antennas. Previous work [1]-[7] has demonstrated a variety of microstrip reflect arrays, using different elements at a range of frequencies. In this paper we describe the use of crossed dipoles as reflecting elements in a microstrip reflectarray. Theory of the solution will be described, with experimental results for a 6" square reflectarray operating at 28 GHz. The performance of crossed dipoles will be directly compared with microstrip patches, in terms of bandwidth and loss. We also comment on the principle of operation of reflectarray elements, including crossed dipoles, patches of variable length, and patch elements with tuning stubs. This research was prompted by the proposed concept of overlaying a flat printed reflectarray on the surface of a spacecraft solar panel. Combining solar panel and antenna apertures in this way would lead to a reduction in weight and simpler deployment, with some loss of flexibility in independently pointing the solar panel and the antenna. Using crossed dipoles as reflectarray elements will minimize the aperture blockage of the solar cells, in contrast to the use of elements such as microstrip patches.

  4. Microstrip reflectarray antenna for the SCANSCAT radar application

    NASA Technical Reports Server (NTRS)

    Huang, John

    1990-01-01

    This publication presents an antenna system that has been proposed as one of the candidates for the SCANSCAT (Scanned Scatterometer) radar application. It is the mechanically steered planar microstrip reflectarray. Due to its thin, lightweight structure, the antenna's mechanical rotation will impose minimum angular momentum for the spacecraft. Since no power-dividing circuitry is needed for its many radiating microstrip patches, this electrically large array antenna demonstrates excellent power efficiency. In addition, this fairly new antenna concept can provide many significant advantages over a conventional parabolic reflector. The basic formulation for the radiation fields of the microstrip reflectarray is presented. This formulation is based on the array theory augmented by the Uniform Geometrical Theory of Diffraction (UTD). A computer code for analyzing the microstrip reflectarray's performances, such as far-field patterns, efficiency, etc., is also listed in this report. It is proposed here that a breadboard unit of this microstrip reflectarray should be constructed and tested in the future to validate the calculated performance. The antenna concept presented here can also be applied in many other types of radars where a large array antenna is needed.

  5. Integration of microbolometers with infrared microstrip antennas

    NASA Astrophysics Data System (ADS)

    Codreanu, Iulian; Boreman, Glenn D.

    2002-12-01

    We report on various integration schemes of infrared microbolometers with microstrip antennas. The first integration design consists of two gold (Au) rectangular microstrip patches coupled along the radiating edges by a narrow niobium (Nb) strip. Devices using silicon oxide are compared to devices using amorphous silicon as antenna substrate. An extension of the twin-patch detector design is the microstrip dipole antenna-coupled microbolometer. Two ways of connecting the device to the contact pads via narrow dc leads are presented and compared. The contribution of the dc leads to the detector response is eliminated by directly connecting the dipole to the contact pads. The thermal isolation of the microbolometer from the silicon wafer is improved by incorporating air into the antenna dielectric substrate. This leads to higher detector responsivity and shifts the resonance towards longer antennas. The implementation of a bridge microstrip dipole antenna structure is also discussed.

  6. Rectenna composed of a circular microstrip antenna

    SciTech Connect

    Itoh, K.; Ohgane, T.; Ogawa, Y.

    1986-01-01

    One of the big problems in the SPS system is reradiation of the harmonic waves generated by the rectifying diode. The authors proposed the use of a circular microstrip antenna (CMSA), since the CMSA has no higher resonance-harmonic of integer multiple of the dominant resonance frequency. However, characteristics of a large rectenna array of CMSA's have not been clarified. This paper is concerned with the absorption efficiency of the rectenna composed of the CMSA. The efficiency is estimated explicitly using an infinite array model. The results show that the absorption efficiency of the infinite rectenna array composed of the CMSA is 100%. Also, this paper considers the effect of the losses of the composed of the CMSA is 100%. Also, this paper considers the effect of the losses of the CMSA. 4 references, 4 figures.

  7. Microstrip patch antennas - Basic properties and some recent advances

    NASA Astrophysics Data System (ADS)

    Lee, Kai-Fong

    1989-10-01

    For high-speed moving vehicles, it is desirable for the antenna to be 'low profile'. One of the early low profile antennas is the slot antenna, the theory of which was developed by Professor Henry G. Booker in a classic paper published in 1946. During the last decade and a half, a relatively new class of radiators known as microstrip patch antennas has received much attention. In addition to being low profile and conformable to a shaped surface, these antennas offer the potential advantages of light weight, low cost, ruggedness, and compatibility with integrated circuit technology. The main disadvantages are narrow bandwidth and the problems associated with copper loss and spurious radiation when the elements form an array. This paper begins with a description of the basic features of microstrip patch antennas, followed by a presentation of some of the research aimed at improving the frequency response and gain, particularly those to which the author and his collaborators have made contributions.

  8. Development of a 20 GHz scanned beam microstrip antenna array with a proximity coupled YBCO feed network

    SciTech Connect

    Mittleman, S.D.; Herd, J.S.; Kenny, J.P.; Poles, L.D.; Champion, M.H.; Rainville, P.J.; Silva, J.H.

    1994-12-31

    A superconducting antenna array with a proximity coupled feed network operating at 20 GHz has been developed. The antenna is a 4x4 array and its performance was measured from 18 GHz to 22 GHz. At temperatures below 80 K, there was a 15 dBi gain measured at several frequencies in this range. The design of a low loss superconducting phase shifter monolithically incorporated into the YBCO feed network is indicated.

  9. Analysis of microstrip antennas using magnetic substrates

    NASA Astrophysics Data System (ADS)

    Vakati, Venkata Jagadish Prasad

    The substrate materials play a major role in the design, production and, most importantly, the performance of the Microstrip antennas. The main goal of this thesis lies in performing a comprehensive and exhaustive study as well as an analysis of how magnetic substrates affect the performance indices of the Microstrip antennas. This project takes into consideration the fact that study of magnetic materials as substrates is a relatively uncharted territory and that a few studies into this field have shown many potential facts. This project narrows the antenna under study to a rectangular Microstrip antenna, due to both the simplicity and the versatility of this structure and the scalability of the study. The project was performed using simulation of Microstrip antenna in CST Microwave Studio with magnetic substrates, over a range of mur, and recording the performance indices of the antenna. The performance indices that were considered for the study were Directivity, Efficiency, Gain, Bandwidth, Resonant frequency and VSWR. The method followed in this study can be easily scaled further to accommodate more performance indices, if needed. The observations were later used to draw practical inferences. Also as an extension, wide band 2x2 Microstrip antenna is designed with an additional degree of freedom where changing the feed distance can cover different bands in GSM frequency.

  10. Two microstrip arrays for interferometric SAR applications

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1993-01-01

    Two types of C-band aircraft interferometric Synthetic Aperture Radar (SAR) are being developed at JPL to measure the ocean wave characteristics. Each type requires two identical antennas with each having a long rectangular aperture to radiate fan-shaped beam(s). One type of these radars requires each of its antennas to radiate a broadside beam that will measure the target's cross-track velocity. The other type, having each of its antennas to radiate two off-broadside pointed beams, will allow the measurement of both the cross-track and the along-track velocities of the target. Because flush mounting of the antenna on the aircraft fuselage is desirable, microstrip patch array is selected for these interferometric SAR antennas. To meet the radar system requirement, each array needs a total of 76 microstrip patches which are arranged in a 38 x 2 rectangular aperture with a physical size of 1.6m x 16.5cm. To minimize the insertion loss and physical real estate of this relatively long array, a combined series/parallel feed technique is used. Techniques to suppress cross-pol radiation and to effectively utilize the RF power are also implemented. Cross-pol level of lower than -30 dB from the co-pol peak and low insertion loss of 0.36 dB have been achieved for both types of arrays. For the type of radar that requires two off-braodside pointed beams, a simple phasing technique is used to achieve this dual-beam capability with adequate antenna gain (20 dBi) and sidelobe level (-14 dB). Both radar arrays have been flight tested on aircraft with excellent antenna performance demonstrated.

  11. Microstrip monopulse antenna for land mobile communications

    NASA Technical Reports Server (NTRS)

    Garcia, Q.; Martin, C.; Delvalle, J. C.; Jongejans, A.; Rinous, P.; Travers, M. N.

    1993-01-01

    Low cost is one of the main requirements in a communication system suitable for mass production, as it is the case for satellite land mobile communications. Microstrip technology fulfills this requirement which must be supported by a low cost tracking system design. The tradeoff led us to a prototype antenna composed of microstrip patches based on electromechanical closed-loop principle; the design and the results obtained are described.

  12. A dual frequency microstrip antenna for Ka band

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Baddour, M. F.

    1985-01-01

    For fixed satellite communication systems at Ka band with downlink at 17.7 to 20.2 GHz and uplink at 27.5 to 30.0 GHz, the focused optics and the unfocused optics configurations with monolithic phased array feeds have often been used to provide multiple fixed and multiple scanning spot beam coverages. It appears that a dual frequency microstrip antenna capable of transmitting and receiving simultaneously is highly desirable as an array feed element. This paper describes some early efforts on the development and experimental testing of a dual frequency annular microstrip antenna. The antenna has potential application for use in conjunction with a monolithic microwave integrated circuit device as an active radiating element in a phased array of phased array feeds. The antenna is designed to resonate at TM sub 12 and TM sub 13 modes and tuned with a circumferential microstrip ring to vary the frequency ratio. Radiation characteristics at both the high and low frequencies are examined. Experimental results including radiating patterns and swept frequency measurements are presented.

  13. Rectangular Microstrip Antenna with Slot Embedded Geometry

    NASA Astrophysics Data System (ADS)

    Ambresh, P. A.; Hadalgi, P. M.; Hunagund, P. V.; Sujata, A. A.

    2014-09-01

    In this paper, a novel design that improves the performance of conventional rectangular microstrip antenna is discussed. Design adopts basic techniques such as probe feeding technique with rectangular inverted patch structure as superstrate, air filled dielectric medium as substrate and slot embedded patch. Prototype of the proposed antenna has been fabricated and various antenna performance parameters such as impedance bandwidth, return loss, radiation pattern and antenna gain are considered for Electromagnetic-study. The antennas are designed for the wireless application operating in the frequency range of 3.3 GHz to 3.6 GHz, and UK based fixed satellite service application (3 GHz to 4 GHz), and are named as single inverted patch conventional rectangular microstrip antenna (SIP-CRMSA) and slots embedded inverted patch rectangular microstrip antenna (SEIP-RMSA), respectively. Measurement outcomes for SEIP-RMSA1 and SEIP-RMSA2 showed the satisfactory performance with an achievable impedance bandwidth of 260 MHz (7 %) and 250 MHz (6.72 %), with return loss (RL) of -11.06 dB and -17.98 dB, achieved gain of 8.17 dB and 5.17 dB with 10% and 8% size reduction in comparison with the conventional patch antenna.

  14. Investigation of certain types of microstrip arrays

    NASA Astrophysics Data System (ADS)

    Chaplin, A. F.; Iakovenko, I. G.; Iashchishin, E. M.

    Results of theoretical and experimental studies of various types of highly directional microstrip arrays are presented. Approaches to a rigorous analysis of microstrip dipole arrays are discussed. The design of three versions of microstrip arrays is considered, and the feeding of such arrays from waveguides and coaxial lines is examined. It is noted that the use of such arrays in the decimeter, centimeter, and millimeter ranges is of particular interest.

  15. Impedance properties of circular microstrip antenna

    NASA Technical Reports Server (NTRS)

    Deshpande, M. D.; Bailey, M. C.

    1983-01-01

    A moment method solution to the input impedance of a circular microstrip antenna excited by either a microstrip feed or a coaxial probe is presented. Using the exact dyadic Green's function and the Fourier transform the problem is formulated in terms of Richmond's reaction integral equation from which the unknown patch current can be solved for. The patch current is expanded in terms of regular surface patch modes and an attachment mode (for probe excited case) which insures continuity of the current at probe/patch junction, proper polarization and p-dependance of patch current in the vicinity of the probe. The input impedance of a circular microstrip antenna is computed and compared with earlier results. Effect of attachment mode on the input impedance is also discussed.

  16. Analysis of a microstrip dipole antenna

    NASA Astrophysics Data System (ADS)

    Rao, B. V.; Sabhnani, N. H.

    1984-02-01

    Assuming a quasi-TEM mode of wave propagation and using a conformal transformation technique, accurate and simple analytic expressions for the characteristic wave resistance and the effective dielectric constant of the microstrip dipole antenna in the mixed dielectric medium have been derived. The theoretical values are in close agreement with the experimental results.

  17. Microstrip Antenna Generates Circularly Polarized Beam

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1986-01-01

    Circular microstrip antenna excited with higher order transverse magnetic (TM) modes generates circularly polarized, conical radiation patterns. Found both theoretically and experimentally that peak direction of radiation pattern is varied within wide angular range by combination of mode selection and loading substrate with materials of different dielectric constants.

  18. Dual-Band Microstrip Antenna With Reactive Loading

    NASA Technical Reports Server (NTRS)

    Davidson, Shayla E.

    1988-01-01

    Effective but bulky coaxial stub replaced. Short-circuited microstrip transmission line serves as reactive loading element for microstrip antenna. Constructed integrally with stripline radiating element, shorted line preserves low microstrip profile and enables tuning of antenna for two-band operation.

  19. Reducing Cross-Polarized Radiation From A Microstrip Antenna

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

    Change in configuration of feed of nominally linearly polarized microstrip-patch transmitting array antenna reduces cross-polarized component of its radiation. Patches fed on opposing sides, in opposite phases. Combination of spatial symmetry and temporal asymmetry causes copolarized components of radiation from fundamental modes of patches to reinforce each other and cross-polarized components of radiation from higher-order modes to cancel each other.

  20. Microstrip technology and its application to phased array compensation

    NASA Technical Reports Server (NTRS)

    Dudgeon, J. E.; Daniels, W. D.

    1972-01-01

    A systematic analysis of mutual coupling compensation using microstrip techniques is presented. A method for behind-the-array coupling of a phased antenna array is investigated as to its feasibility. The matching scheme is tried on a rectangular array of one half lambda 2 dipoles, but it is not limited to this array element or geometry. In the example cited the values of discrete components necessary were so small an L-C network is needed for realization. Such L-C tanks might limit an otherwise broadband array match, however, this is not significant for this dipole array. Other areas investigated were balun feeding and power limits of spiral antenna elements.

  1. Microstrip antennas on/in anisotropic material layers

    NASA Astrophysics Data System (ADS)

    Yang, Hung-Yu; Castaneda, Jesse A.; Nakatani, Akifumi

    1992-11-01

    Accurate fullwave analyses of microstrip dipoles on multi-layer substrates with generalized anisotropic permittivity and permeability have been developed. The solution to the problem of microstrip dipoles on/in gyrotropic substrates has been obtained. The potential of electronically shaped, scanned, and gain enhanced element factors with ferrite substrates has been theoretically demonstrated. The scattering and radiation problems were solved. The use of biased ferrite substrates to simultaneously reduce RCS and preserve antenna in-band gain has also been described. Infinite phased arrays of microstrip dipoles and probe-fed patches on general anisotropic multi-layer substrates have been analyzed. All the solutions involve the dyadic Green's function for the anisotropic layered structure and the application of the method of moments to an electric field integral equation.

  2. A Low Loss Microstrip Antenna for Radiometric Applications

    NASA Technical Reports Server (NTRS)

    Wahid, Parveen

    2000-01-01

    The design and analysis of a series-fed, low-loss, inverted microstrip array antenna, operating at 1.413 GHz is presented. The antenna is composed of two subarrays. Each subarray consists of an equal number of microstrip patches all connected together with microstrip lines. In the first design microstrip array for linear polarization is presented which incorporated a series feeding technique. The next design, which is capable of dual linear polarization (V-polarization and H-polarization), utilizes a corporate feed network for the V-pol and series feed arrangement for the H-pol. The first element of each subarray for H-pol is coaxially fed with a 180 deg phase difference. This approach ensures a symmetric radiation pattern on broadside in H-pol. For the V-pol two feeds are in the same phase on the two subarrays ensuring a broadside beam in V-pol. The designs presented here are simulated using the IE3D code that utilizes the method of moments. Measured results are compared with simulated results and show good agreement.

  3. A Fast MoM Solver (GIFFT) for Large Arrays of Microstrip and Cavity-Backed Antennas

    SciTech Connect

    Fasenfest, B J; Capolino, F; Wilton, D

    2005-02-02

    A straightforward numerical analysis of large arrays of arbitrary contour (and possibly missing elements) requires large memory storage and long computation times. Several techniques are currently under development to reduce this cost. One such technique is the GIFFT (Green's function interpolation and FFT) method discussed here that belongs to the class of fast solvers for large structures. This method uses a modification of the standard AIM approach [1] that takes into account the reusability properties of matrices that arise from identical array elements. If the array consists of planar conducting bodies, the array elements are meshed using standard subdomain basis functions, such as the RWG basis. The Green's function is then projected onto a sparse regular grid of separable interpolating polynomials. This grid can then be used in a 2D or 3D FFT to accelerate the matrix-vector product used in an iterative solver [2]. The method has been proven to greatly reduce solve time by speeding up the matrix-vector product computation. The GIFFT approach also reduces fill time and memory requirements, since only the near element interactions need to be calculated exactly. The present work extends GIFFT to layered material Green's functions and multiregion interactions via slots in ground planes. In addition, a preconditioner is implemented to greatly reduce the number of iterations required for a solution. The general scheme of the GIFFT method is reported in [2]; this contribution is limited to presenting new results for array antennas made of slot-excited patches and cavity-backed patch antennas.

  4. Radial microstrip slotline feed network for circular mobile communications array

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

    1994-04-01

    In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

  5. Radial microstrip slotline feed network for circular mobile communications array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

    1994-01-01

    In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

  6. Dual-band reactively loaded microstrip antenna

    NASA Technical Reports Server (NTRS)

    Richards, W. F.; Long, S. A.; Davidson, S. E.

    1985-01-01

    A previously derived theory is applied to a microstrip antenna with a reactive load to produce a dual-band radiator. A model consisting of a rectangular patch radiator loaded with a variable length short-circuited coaxial stub was investigated experimentally. Comparisons of theoretical predictions and experimental data are made for the impedance and resonant frequencies as a function of the position of the load, the length of the stub, and the characteristic impedance of the stub.

  7. Superconducting microstrip antennas: An experimental comparison of two feeding methods

    SciTech Connect

    Richard, M.A.; Claspy, P.C. ); Bhasin, K.B. . Lewis Research Center)

    1993-07-01

    The recent discovery of high-temperature superconductors (HTS's) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. In this paper, two methods for feeding HTS microstrip antennas at K and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals.

  8. Superconducting Microstrip Antennas: An Experimental Comparison of Two Feeding Methods

    NASA Technical Reports Server (NTRS)

    Richard, Mark A.; Claspy, Paul C.; Bhasin, Kul B.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gas-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals

  9. Superconducting microstrip antennas - An experimental comparison of two feeding methods

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Bhasin, Kul B.; Claspy, Paul C.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals.

  10. Implantable multilayer microstrip antenna for retinal prosthesis: antenna testing.

    PubMed

    Permana, Hans; Fang, Qiang; Rowe, Wayne S T

    2012-01-01

    Retinal prosthesis has come to a more mature stage and become a very strategic answer to Retinitis Pigmentosa (RP) and Age-related Macular Degeneration (AMD) diseases. In a retinal prosthesis system, wireless link holds a great importance for the continuity of the system. In this paper, an implantable multilayer microstrip antenna was proposed for the retinal prosthesis system. Simulations were performed in High Frequency Structure Simulator (HFSS) with the surrounding material of air and Vitreous Humor fluid. The fabricated antenna was measured for characteristic validation in free space. The results showed that the real antenna possessed similar return loss and radiation pattern, while there was discrepancy with the gain values. PMID:23366231

  11. Trislot-cavity microstrip antenna

    NASA Technical Reports Server (NTRS)

    Ellis, H., Jr.

    1981-01-01

    Flush-mountable assembly composed of disk radiator sandwiched between planes of metal-clad dielectric board has greater bandwidths and beamwidths than simple disk antenna. Conducting planes connect so that disk is enclosed in cavity with Y-shaped slot in top plane. Cavity is excited by microwave energy from disk and radiates from trislot aperature.

  12. Characteristics of microstrip dipole antennas in a periodic structure with dielectric layers

    NASA Astrophysics Data System (ADS)

    Grinev, A. Iu.; Kotov, Iu. V.

    Microstrip dipole antennas in a periodic antenna array with dielectric layers are analyzed on the basis of a rigorous solution of an integral equation of the first kind with respect to the electric-field distribution on the dipole. Numerical results are presented on the partial radiation pattern of the antenna, the total input impedance, and the amplitude-phase distribution of the electric current on the dipole. The optimization of the antenna is considered.

  13. Advanced microstrip antenna developments. Volume 2: Microstrip GPS antennas for general aviation aircraft

    NASA Astrophysics Data System (ADS)

    Sanford, G. G.; Gross, B. D.

    1982-03-01

    This report describes the application of microstrip antenna technology to the design of general aviation (G/A) aircraft antennas for use with the Global Positioning System (GPS). For most G/A aircraft, only single frequency operation will be required. However, air-carrier and some large corporate aircraft may make use of dual-frequency operation. For this reason, some dual-frequency designs have been investigated. The main effort was given to the design of antennas with broad beamwidths which could be switched or steered to compensate for aircraft maneuvers, with the goal of maintaining near-hemispherical carriage in flight. A hybrid microstrip crossed-slot and sleeve-dipole element used with a suitable combining network gives a suitable, controllable broad-beam pattern. This element and its performance are described. In addition, radiation patterns are presented using scale-model aircraft and simple crossed-slot antennas.

  14. Cross-polarization level in radiation from a microstrip dipole antenna

    NASA Astrophysics Data System (ADS)

    Hoorfar, Ahmad; Gupta, Kuldip C.; Chang, David C.

    1988-09-01

    A description is given of the cross-polarization level in radiation from a small horizontal electric dipole (HED) on a flat grounded dielectric substrate. The study is directed toward the design of a very low cross-polarization level in a linear array of microstrip antenna elements. Field expressions for a copolarized and crosspolarized microstrip HED for any arbitrary dipole orientation and array direction are derived.

  15. A Microstrip Patch-Fed Short Backfire Antenna for the Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) Array

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Kory, Carol L.; Lambert, Kevin M.; Acosta, Roberto J.

    2006-01-01

    Short Backfire Antennas (SBAs) are widely utilized for mobile satellite communications, tracking, telemetry, and wireless local area network (WLAN) applications due to their compact structure and excellent radiation characteristics [1-3]. Typically, these SBA s consist of an excitation element (i.e., a half-wavelength dipole), a reflective bottom plane, a planar sub-reflector located above the "exciter", and an outer circular rim. This configuration is capable of achieving gains on the order of 13-15 dBi, but with relatively narrow bandwidths (approx.3%-5%), making it incompatible with the requirements of the next generation enhanced Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) array [1]. Several attempts have been made to enhance the bandwidth performance of the common dipole-fed SBA by employing various other feeding mechanisms (e.g., waveguide, slot) with moderate success [4-5]. In this paper, a novel method of using a microstrip patch is employed for the first time to excite an SBA. The patch element is fed via two H-shaped slots electromagnetically coupled to a broadband hybrid coupler to maintain a wide bandwidth, as well as provide for dual circular polarization capabilities.

  16. Back-feed type circularly polarized microstrip disk antennas by one-point feed

    NASA Astrophysics Data System (ADS)

    Haneishi, M.; Yoshida, S.; Oka, N.

    1980-06-01

    A new circularly polarized microstrip disk antenna which is fed from a point on the substrate bottom surface is proposed and its radiation characteristics, element mutual conductance and radiation efficiency near resonance points are analyzed. Further, an eight-element array consisting of this disk antenna as an element is introduced and its effectiveness is discussed.

  17. Performance of a four-element Ka-band high-temperature superconducting microstrip antenna

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Bhasin, K. B.; Gilbert, C.; Metzler, S.; Koepf, G.; Claspy, P. C.

    1992-01-01

    Superconducting four-element microstrip array antennas operating at 30 GHz have been designed and fabricated on a lanthanum aluminate (LaAlO3) substrates. The experimental performance of these thin film Y-Ba-Cu-O superconducting antennas is compared with that of identical antenna patterned with evaporated gold. Efficiency measurements of these antennas show an improvement of 2 dB at 70 K and as much as 3.5 dB at 40 K in the superconducting antenna over the gold antenna.

  18. RHCP- DESIGNING RECTANGULAR RIGHT-HANDED CIRCULARLY POLARIZED MICROSTRIP ANTENNAS

    NASA Technical Reports Server (NTRS)

    Davidson, S. E.

    1994-01-01

    RHCP, the Right-Handed, Circularly Polarized Microstrip Antenna program, aids in the design of a rectangular antenna element, given the desired frequency of operation and substrate characteristics. RHCP begins the design calculations based on a square element with linear polarization. The effective dielectric constant and changes in electrical length due to fringing at the radiating element edges are taken into account. A coaxial feed is inset with 50 ohms input impedance. By placing the feed such that two orthonormal modes are produced in the antenna cavity, right- or left-handed circular polarization is obtained. Input to RHCP consists of desired frequency, dielectric constant, and substrate thickness. Output consists of the final rectangular geometry, the proposed feed inset placement, and actual input impedance. RHCP has been used successfully for frequencies between 2 and 15 GHz for thin substrates. This program was used to fabricate antenna elements for the S-band quad antennas on board the Space Shuttle, and is a part of the design project for the S-band phased array antenna radiating aperture. RHCP is written in FORTRAN 77 for interactive execution and has been implemented on a DEC VAX series computer operating under VMS. This program was developed in 1985.

  19. Series-fed circularly polarized microstrip antennas with broad bandwidth

    NASA Astrophysics Data System (ADS)

    Mao, Shau-Gang; Chen, Shiou-Li; Yeh, Jen-Chun; Lin, Tien-Min

    2007-08-01

    A new series-fed circularly polarized antenna (SFCPA) in microstrip configuration, which consists of a traveling-wave-type crank-line antenna (CLA) and a resonant-type square-ring slot antenna (SRSA), is developed. Unlike the conventional crank-line (CL) antenna array with an open end or a resistive load, the proposed SFCPA uses the SRSA at the termination of the CLA and thus exhibits not only a broad circularly polarized (CP) bandwidth but also a large antenna gain. The characteristics of the SFCPA, including the leaky-wave radiation and the circular polarization, are examined in terms of the dispersion diagram and the current distribution. The SFCPA with the two-cell CLA and the terminated SRSA is fabricated and measured to demonstrate the 10-dB return loss and 3-dB axial ratio (AR) bandwidths of 34.3% and 30.5%, respectively. The frequency-scanning radiation patterns with a 5-7 dBi antenna gain are also presented in the operating band.

  20. A finite difference approach to microstrip antenna design

    SciTech Connect

    Barth, M.J.; Bevensee, R.M.; Pennock, S.T.

    1986-12-01

    Microstrip antennas have received increased attention in recent years, due to their size and cost advantages. Analysis of the microstrip structure has proved difficult due to the presence of the dielectric substrate, particularly for complex geometries. One possible approach to a solution is the use of a finite difference computer code to model a proposed microstrip antenna design. The models are easily constructed and altered, and code versions are available which allow input impedance or far-field patterns to be calculated. Results for some simple antenna geometries will be presented.

  1. Research on planar antennas and arrays - 'Structures Rayonnantes'

    NASA Astrophysics Data System (ADS)

    Daniel, J. P.; Dubost, G.; Terret, C.; Citerne, J.; Drissi, M.

    1993-02-01

    Radiating antenna structures related to flat and wire antennas developed by the laboratory 'Structures Rayonnantes' of the University of Rennes I (France) are discussed with emphasis on flat antennas and arrays studied during the last three years and on their typical applications. Particular attention is given to basic planar radiating sources including patches with coaxial or microstrip feed, printed slots, slot-fed patches, slot-loaded patches, and electromagnetic coupled dipoles and patches; planar arrays including planar phased and planar passive arrays and dual-beam printed antennas; and arrays of microstrip dipoles.

  2. Use of microstrip patch antennas in grain permittivity measurement

    USGS Publications Warehouse

    El Sabbagh, M.A.; Ramahi, O.M.; Trabelsi, S.; Nelson, S.O.; Khan, L.

    2003-01-01

    In this paper, a compact size free-space setup is proposed for the measurement of complex permittivity of granular materials. The horn antennas in the conventional setup are replaced by microstrip patch antennas which is a step toward system miniaturization. The experimental results obtained are in good agreement with those obtained with horn antennas.

  3. Scattering from arbitrarily shaped microstrip patch antennas

    NASA Technical Reports Server (NTRS)

    Shively, David G.; Deshpande, Manohar D.; Cockrell, Capers R.

    1992-01-01

    The scattering properties of arbitrarily shaped microstrip patch antennas are examined. The electric field integral equation for a current element on a grounded dielectric slab is developed for a rectangular geometry based on Galerkin's technique with subdomain rooftop basis functions. A shape function is introduced that allows a rectangular grid approximation to the arbitrarily shaped patch. The incident field on the patch is expressed as a function of incidence angle theta(i), phi(i). The resulting system of equations is then solved for the unknown current modes on the patch, and the electromagnetic scattering is calculated for a given angle. Comparisons are made with other calculated results as well as with measurements.

  4. Gain Improvement of Microstrip Patch Antenna Using CLS Split Ring Resonator Metamaterial

    NASA Astrophysics Data System (ADS)

    Katiyar, Pankaj Rameshchandra; Wan Mahadi, Wan Nor Liza Binti

    2015-03-01

    Metamaterials are artificial materials with negative permittivity and permeability. Metamaterials due to their unique negative parameter are capable of focusing the electromagnetic energy incident upon them. This focusing of electromagnetic energy is used to increase the gain of microstrip patch antenna. A capacitive loaded strip (CLS)-loaded split ring resonator is used to form a multilayer array of metamaterial and used in front of microstrip patch antenna to enhance far-field gain of antenna. An accurate simulation model is created and analyzed using CST. The simulated model is then fabricated and measured in fully anechoic chamber for validation. The far-field gain of regular patch antenna with and without metamaterial is measured in anechoic chamber. The increase in gain by 4 dB is measured at 95 mm from antenna. The beam focusing property is also evident from 3 dB beamwidth of antenna which is reduced to 42.01°.

  5. A design concept for an MMIC microstrip phased array

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Smetana, J.; Acosta, R.

    1986-01-01

    A conceptual design for a microstrip phased array with monolithic microwave integrated circuit (MMIC) amplitude and phase controls is described. The MMIC devices used are 20 GHz variable power amplifiers and variable phase shifters recently developed by NASA contractors for applications in future Ka band advanced satellite communication antenna systems. The proposed design concept is for a general NxN element array of rectangular lattice geometry. Subarray excitation is incorporated in the MMIC phased array design to reduce the complexity of the beam forming network and the number of MMIC components required. The proposed design concept takes into consideration the RF characteristics and actual phyical dimensions of the MMIC devices. Also, solutions to spatial constraints and interconnections associated with currently available packaging designs are discussed. Finally, the design of the microstrip radiating elements and their radiation characteristics are examined.

  6. Efficient analysis for infinite microstrip dipole arrays

    NASA Astrophysics Data System (ADS)

    Wright, S. M.; Lo, Y. T.

    1983-11-01

    A moment method analysis of infinite microstrip dipole arrays which uses an efficient technique to evaluate the generalized impedance matrix is described. A particularly simple formulation is obtained through the use of the periodic Green function. Results for the reflection coefficient magnitude against scan angle are given for a typical array.

  7. Microstrip Antenna for Remote Sensing of Soil Moisture and Sea Surface Salinity

    NASA Technical Reports Server (NTRS)

    Ramhat-Samii, Yahya; Kona, Keerti; Manteghi, Majid; Dinardo, Steven; Hunter, Don; Njoku, Eni; Wilson, Wiliam; Yueh, Simon

    2009-01-01

    This compact, lightweight, dual-frequency antenna feed developed for future soil moisture and sea surface salinity (SSS) missions can benefit future soil and ocean studies by lowering mass, volume, and cost of the antenna system. It also allows for airborne soil moisture and salinity remote sensors operating on small aircraft. While microstrip antenna technology has been developed for radio communications, it has yet to be applied to combined radar and radiometer for Earth remote sensing. The antenna feed provides a key instrument element enabling high-resolution radiometric observations with large, deployable antennas. The design is based on the microstrip stacked-patch array (MSPA) used to feed a large, lightweight, deployable, rotating mesh antenna for spaceborne L-band (approximately equal to 1 GHz) passive and active sensing systems. The array consists of stacked patches to provide dual-frequency capability and suitable radiation patterns. The stacked-patch microstrip element was designed to cover the required L-band center frequencies at 1.26 GHz (lower patch) and 1.413 GHz (upper patch), with dual-linear polarization capabilities. The dimension of patches produces the required frequencies. To achieve excellent polarization isolation and control of antenna sidelobes for the MSPA, the orientation of each stacked-patch element within the array is optimized to reduce the cross-polarization. A specialized feed-distribution network was designed to achieve the required excitation amplitude and phase for each stacked-patch element.

  8. Thin conformal antenna array for microwave power conversions

    NASA Technical Reports Server (NTRS)

    Dickinson, R. M. (Inventor)

    1978-01-01

    A structure of a circularly polarized, thin conformal, antenna array which may be mounted integrally with the skin of an aircraft employs microstrip elliptical elements and interconnecting feed lines spaced from a circuit ground plane by a thin dielectric layer. The feed lines are impedance matched to the elliptical antenna elements by selecting a proper feedpoint inside the periphery of the elliptical antenna elements. Diodes connected between the feed lines and the ground plane rectify the microwave power, and microstrip filters (low pass) connected in series with the feed lines provide dc current to a microstrip bus. Low impedance matching strips are included between the elliptical elements and the rectifying and filtering elements.

  9. New Optically Controlled Frequency-Agile Microstrip Antenna

    NASA Astrophysics Data System (ADS)

    Ehteshami, Nasrin; Sathi, Vahid

    2013-01-01

    A novel class of microstrip antennas composed of organic semiconductor polymer [poly(3-hexylthiophene) (P3HT)] is proposed for frequency sweeping applications. The permittivity of the P3HT film is measured using the reflective coaxial method for illuminated and nonilluminated states. Resonant frequencies of the proposed antennas instantly change on changing the optical illumination intensity from an adjustable white-light source. Two different antenna configurations (square and square ring) are designed and tested experimentally. The square ring antenna is able to sweep a broader frequency band (1.5 GHz). The gain and radiation efficiency of the proposed square antenna are compared with the corresponding copper microstrip antenna. The proposed antennas have acceptable resonant and radiation characteristics, albeit with modest radiation efficiency.

  10. On the modeling and experimentation of electromagnetically coupled microstrip dipole arrays in a substrate-superstrate

    NASA Astrophysics Data System (ADS)

    Alexopoulos, Nicholaos G.; Yang, Hung-Ya

    The thrust of the research has been to develop the methodology for the modeling and design antenna arrays and microstrip discontinuities for microwave circuit applications. The thesis involves several key contributions in the subject areas of modeling microstrip discontinuities, microstrip transitions, and the synthesis of microstrip dipole arrays. This work has generated several journal publications within which one finds a fundamental contribution to the understanding of the above mentioned subjects. The analysis and the generated computer programs serve as practical tools for the design of microstrip circuits and microstrip dipole arrays. An evolution of the work has led to the understanding of microstrip discontinuity effects. In particular the theory has been extended to model microstrip bends, T-junctions, four ports, etc. In each case the algorithms account for a precise description of energy loss at discontinuities due to radiation loss and surface wave loss. These models have also been substantiated with experiment. The models are now extended to provide precise designs for microstrip corporate feeds. This will lead to the design of two dimensional transversely fed electromagnetically coupled dipole arrays.

  11. A user's manual for the Loaded Microstrip Antenna Code (LMAC)

    NASA Technical Reports Server (NTRS)

    Forrai, D. P.; Newman, E. H.

    1988-01-01

    The use of the Loaded Microstrip Antenna Code is described. The geometry of this antenna is shown and its dimensions are described in terms of the program outputs. The READ statements for the inputs are detailed and typical values are given where applicable. The inputs of four example problems are displayed with the corresponding output of the code given in the appendices.

  12. Nonplanar linearly tapered slot antenna with balanced microstrip feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.; Perl, Thomas D.

    1992-01-01

    A nonplanar linearly tapered slot antenna (LTSA) has been fabricated and tested at frequencies from 8 to 32 giga-Hz. The LTSA is excited by a broadband balanced microstrip transformer. The measured results include the input term return loss as well as the radiation pattern of the antenna.

  13. A bandwidth enhancement method for microstrip antennas

    NASA Astrophysics Data System (ADS)

    Katehi, Pisti B.; Alexopoulos, Nicolaos G.; Hsia, I. Y.

    1987-01-01

    Bandwidth enhancement methods for electromagnetically coupled microstrip dipoles are discussed. It is demonstrated that if parasitic metallic strips are incorporated in the structure either co-planar and parallel to the embedded microstrip transmission line open end, or between the transmission line and the microstrip dipole, then substantial bandwidth enhancement results. Experimental verification of this model is introduced for a bandwidth definition based on the frequency range which satisfies a voltage standing-wave ratio of less than 2 criterion. The theoretical model which accounts for radiation from the microstrip dipole, the parasitics, and the transmission line is verified.

  14. Dual band triangular slotted stacked microstrip antenna for wireless applications

    NASA Astrophysics Data System (ADS)

    Singh, Vinod; Ali, Zakir; Singh, Ashutosh; Ayub, Shahanaz

    2013-06-01

    In this paper stacked configuration of microstrip antenna is used to produce dual wide band which is suitable for various wireless applications. Using triangular slot and stacking of foam substrate of dielectric constant 1, two bands of bandwidth 18.70% and 12.10% is obtained. The antenna is fed by coaxial probe feeding technique. The proposed patch antenna is designed on the foam substrate and simulated on the Zeland IE3D software.

  15. Feasibility Study of Optically Transparent Microstrip Patch Antenna

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1997-01-01

    The paper presents a feasibility study on optically transparent patch antennas with microstrip line and probe feeds. The two antennas operate at 2.3 GHz and 19.5 GHz respectively. They are constructed from a thin sheet of clear polyester with an AgHT-8 optically transparent conductive coating. The experimental results show good radiation patterns and input impedance match. The antennas have potential applications in mobile wireless communications.

  16. Improved bandwidth of microstrip antennas using parasitic elements

    NASA Astrophysics Data System (ADS)

    Wood, C.

    1980-08-01

    A method is described of doubling the bandwidth of rectangular microstrip patch antennas by locating capacitively excited m-wavelength/4 short circuit parasitic elements at their radiating edges. The antenna characteristics are explained in terms of an antiphase mode of a pair of coupled resonators, and it is shown that the bandwidth improvement is independent of the coupling capacitance. Experimental results are presented for both linearly and circularly polarized antennas which support the theoretical predictions.

  17. Wireless OAM transmission system based on elliptical microstrip patch antenna.

    PubMed

    Chen, Jia Jia; Lu, Qian Nan; Dong, Fei Fei; Yang, Jing Jing; Huang, Ming

    2016-05-30

    The multiplexing transmission has always been a focus of attention for communication technology. In this paper, the radiation characteristics of circular microstrip patch antenna was firstly analyzed based on cavity model theory, and then spiral beams carrying orbital angular momentum (OAM) were generated, using elliptical microstrip patch antenna, with a single feed probe instead of a standard circular patch with two feedpoints. Moreover, by combining the proposed elliptic microstrip patch antenna with Universal Software Radio Peripheral (USRP), a wireless OAM transmission system was established and the real-time transmission of text, image and video in a real channel environment was realized. Since the wireless OAM transmission has the advantage of good safety and high spectrum utilization efficiency, this work has theoretical significance and potential application. PMID:27410080

  18. Linearly tapered slot antenna circular array for mobile communications

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

    1993-01-01

    The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

  19. Compact, Lightweight Dual- Frequency Microstrip Antenna Feed for Future Soil Moisture and Sea Surface Salinity Missions

    NASA Technical Reports Server (NTRS)

    Yueh, Simon H.; Wilson, William J.; Njoku, Eni; Hunter, Don; Dinardo, Steve; Kona, Keerti S.; Manteghi, Majid; Gies, Dennis; Rahmat-Samii, Yahya

    2004-01-01

    The development of a compact, lightweight, dual frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described. The design is based on the microstrip stacked-patch array (MSPA) to be used to feed a large lightweight deployable rotating mesh antenna for spaceborne L-band (approx. 1 GHz) passive and active sensing systems. The design features will also enable applications to airborne sensors operating on small aircrafts. This paper describes the design of stacked patch elements, 16-element array configuration and power-divider beam forming network The test results from the fabrication of stacked patches and power divider were also described.

  20. Slot-coupled excitation of microstrip dipole antennas

    NASA Astrophysics Data System (ADS)

    Ittipiboon, A.; Roscoe, D.; Cuhaci, M.; Antar, Y. M. M.

    1992-01-01

    The slot-coupled method is proposed as an alternative to the popular electromagnetically coupled technique (EMC) for feeding microstrip dipole antennas. This letter describes the basic design procedure and some key advantages of this method over EMC. Experimental results confirm the effective and practical performance of the proposed structure.

  1. Full W-band Microstrip Fed Vivaldi Antenna

    NASA Astrophysics Data System (ADS)

    Rebollo, Ainara; Gonzalo, Ramón; Ederra, Iñigo

    2016-03-01

    A full W-band Vivaldi antenna is proposed. The selected feeding technique implements a broadband slotline to microstrip transition which allows obtaining return loss higher than 10 dB in the full W-band. The proposed configuration is compatible with standard manufacturing techniques such as photo-lithography or laser milling.

  2. Full W-band Microstrip Fed Vivaldi Antenna

    NASA Astrophysics Data System (ADS)

    Rebollo, Ainara; Gonzalo, Ramón; Ederra, Iñigo

    2016-08-01

    A full W-band Vivaldi antenna is proposed. The selected feeding technique implements a broadband slotline to microstrip transition which allows obtaining return loss higher than 10 dB in the full W-band. The proposed configuration is compatible with standard manufacturing techniques such as photo-lithography or laser milling.

  3. Phased array antenna control

    NASA Technical Reports Server (NTRS)

    Doland, G. D. (Inventor)

    1978-01-01

    Several new and useful improvements in steering and control of phased array antennas having a small number of elements, typically on the order of 5 to 17 elements are provided. Among the improvements are increasing the number of beam steering positions, reducing the possibility of phase transients in signals received or transmitted with the antennas, and increasing control and testing capacity with respect to the antennas.

  4. Ka-band MMIC microstrip array for high rate communications

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Raquet, C. A.; Tolleson, J. B.; Sanzgiri, S. M.

    1991-01-01

    In a recent technology assessment of alternative communication systems for the space exploration initiative (SEI), Ka-band (18 to 40 GHz) communication technology was identified to meet the mission requirements of telecommunication, navigation, and information management. Compared to the lower frequency bands, Ka-band antennas offer higher gain and broader bandwidths; thus, they are more suitable for high data rate communications. Over the years, NASA has played an important role in monolithic microwave integrated circuit (MMIC) phased array technology development, and currently, has an ongoing contract with Texas Instrument (TI) to develop a modular Ka-band MMIC microstrip subarray (NAS3-25718). The TI contract emphasizes MMIC integration technology development and stipulates using existing MMIC devices to minimize the array development cost. The objective of this paper is to present array component technologies and integration techniques used to construct the subarray modules.

  5. Multiple band circularly polarized microstrip antenna

    NASA Technical Reports Server (NTRS)

    Yu, I. P. (Inventor)

    1980-01-01

    A multiple antenna assembly for communicating electromagnetic radiation is disclosed. An antenna element stack is constructed of a plurality of elliptical lamina antenna elements mutally separated by layers of dielectric material, and separated from a ground plane by dielectric material. The antenna assembly is coupled through a feed line in contact with the top antenna element. A conductor joins the remaining antenna elements to the ground plane. Each individual antenna element is operable for communication reception and transmission within a frequency band determined by the size of the particular antenna element. The sizes of the antenna elements may be selected to provide electromagnetic radiation communication over several distinct frequency bands, or to connect the individual bands into a broad band.

  6. Microstrip-antenna design for hyperthermia treatment of superficial tumors.

    PubMed

    Montecchia, F

    1992-06-01

    Microstrip antennas have many different advantages over other RF/MW radiative applicators employed for superficial hyperthermia treatment. This is mainly due to their compact and body-conformable structure as well as to printed circuit board techniques, both of which allow a wide design flexibility for superficial tumor heating. Among the wide variety of radiator configurations, three microstrip antennas of increasing complexity with electromagnetic and heating characteristics potentially suitable as applicators for superficial hyperthermia have been designed, developed, and tested in different radiative conditions: a microstrip disk, a microstrip annular-slot, and a microstrip spiral. Electromagnetic design criteria are presented together with the determinations of the applicator return loss versus frequency and thermograms of the near-field heating pattern in muscle-like phantom. The results are in good agreement with theory and indicate that: i) the operating frequency is either single or multiple according to the applicator-mode, "resonant" or "traveling-wave," and can be chosen in the useful frequency range for hyperthermia (200-1000 MHz) according to the tumor cross-section and depth; ii) the heating pattern flexibility increases going from the simple geometry disk to the annular-slot and spiral applicators; iii) a distilled-water bolus is required; iv) the annular-slot applicator exhibits the highest efficiency, while the spiral applicator provides the best performance. PMID:1601439

  7. Microstrip-antenna design for hyperthermia treatment of superficial tumors

    SciTech Connect

    Montecchia, F. )

    1992-01-01

    Microstrip antennas have many different advantages over other RF/MW radiative applicators employed for superficial hyperthermia treatment. This is mainly due to their compact and body-conformable structure as well as to printed circuit board techniques, both of which allow a wide design flexibility for superficial tumor heating. Among the wide variety of radiator configurations, three microstrip antennas of increasing complexity with electromagnetic and heating characteristics potentially suitable as applicators for superficial hyperthermia have been designed, developed, and tested in different radiative condition: a microstrip disk, a microstrip annular-slot, and a microstrip spiral. Electromagnetic design criteria are presented together with the determinations of the applicator return loss versus frequency and thermograms of the near-field heating pattern in muscle-like phantom. The results are in good agreement with theory and indicated that: the operating frequency is either single or multiple according to the applicator-mode, 'resonant' or 'traveling-wave', and can be chosen in the useful frequency range for hyperthermia according to the tumor cross-section and depth; the heating pattern flexibility increases going form the simple geometry disk to the annular-slot and spiral applicators; a distilled-water bolus is required; the annular-slot applicator exhibits the highest efficiency, while the spiral applicator provides the best performance.

  8. Front-Side Microstrip Line Feeding a Raised Antenna Patch

    NASA Technical Reports Server (NTRS)

    Hodges, Richard; Hoppe, Daniel

    2005-01-01

    An improved design concept for a printed-circuit patch antenna and the transmission line that feeds the patch calls for (1) a microstrip transmission line on the front (radiative) side of a printed-circuit board based on a thin, high-permittivity dielectric substrate; (2) using the conductor covering the back side of the circuit board as a common ground plane for both the microstrip line and the antenna patch; (3) supporting the antenna patch in front of the circuit board on a much thicker, lower-permittivity dielectric spacer layer; and (4) connecting the microstrip transmission line to the patch by use of a thin wire or narrow ribbon that extends through the thickness of the spacer and is oriented perpendicularly to the circuit-board plane. The thickness of the substrate is typically chosen so that a microstrip transmission line of practical width has an impedance between 50 and 100 ohms. The advantages of this design concept are best understood in the context of the disadvantages of prior design concepts, as explained

  9. Coaxial phased array antenna

    NASA Astrophysics Data System (ADS)

    Ellis, H., Jr.

    1980-08-01

    A coaxial antenna array for communicating circularly polarized electromagnetic radiation is disclosed. A pair of open ended antenna cavities is coaxially constructed and operates by excitation of linear radiation elements arranged within each of the cavities. A pair of crossed dipole radiation devices is centered within the inner cavity and operated by means of a phase shifting network circuit to transmit as well as receive circularly polarized radiation. Four monopole radiation devices are symmetrically arranged to operate in the outer cavity in phase quadrature by means of the phase shifting network circuit to both transmit and receive circularly polarized electromagnetic radiation. Combined operation of the two antenna cavities with a 180 deg phase differential between the fields related to the two antenna cavities provides a broad beam, relatively wide frequency bandwidth communication capability. Particular embodiments disclosed feature a generally square cavity array as well as a circular cavity array.

  10. Coaxial phased array antenna

    NASA Technical Reports Server (NTRS)

    Ellis, H., Jr. (Inventor)

    1980-01-01

    A coaxial antenna array for communicating circularly polarized electromagnetic radiation is disclosed. A pair of open ended antenna cavities is coaxially constructed and operates by excitation of linear radiation elements arranged within each of the cavities. A pair of crossed dipole radiation devices is centered within the inner cavity and operated by means of a phase shifting network circuit to transmit as well as receive circularly polarized radiation. Four monopole radiation devices are symmetrically arranged to operate in the outer cavity in phase quadrature by means of the phase shifting network circuit to both transmit and receive circularly polarized electromagnetic radiation. Combined operation of the two antenna cavities with a 180 deg phase differential between the fields related to the two antenna cavities provides a broad beam, relatively wide frequency bandwidth communication capability. Particular embodiments disclosed feature a generally square cavity array as well as a circular cavity array.

  11. Moment method analysis of microstrip antennas over a wide frequency range

    NASA Technical Reports Server (NTRS)

    Kwan, B. W.; Newman, E. H.

    1985-01-01

    Expressions for the self and mutual impedance between microstrip antenna modes on a grounded dielectric slab are presented. The mutual impedance between the microstrip modes and a vertical current filament in the dielectric is also presented. These are the quantities required in a method of moments analysis of the microstrip antenna. Entire domain expansion modes, suitable for representing the microstrip current over a broad frequency range, are used. Efficient methods for the evaluation of the mutual impedance elements are described.

  12. Scanning and Defocusing Properties of Microstrip Reflectarray Antennas

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2011-01-01

    A symmetric reflectarray, consisting of variable-size square patch elements with a commonly used mathematical model for the horn in the form of a cosine function, has been designed using the transmit mode technique for different f/D ratios with 10 dB edge taper. Subsequently, the antennas were analyzed for the radiation pattern and gain. The infinite array model was used to determine the reflection phase of each patch element in the design and analysis codes. By displacing the feed laterally, the scan characteristics were obtained, such as the beam deviation factor, gain loss, and pattern degradation. The properties of reflect arrays were compared to those of the conventional paraboloidal reflectors. The same procedure was used to study the scan properties of offset reflectarrays. There is no cross-polarized radiation in the principal planes for a symmetric system. Cross-polarized radiation exists in non-principal planes off broadside in symmetric systems, with greater levels for larger values of subtended angles. Such cross-polarized radiation level increases with subtended angle just as cross-polarization level increases with decreasing values of f/D ratios for symmetric paraboloids in non-principal planes. Pattern distortions and gain loss were found to be more severe in the case of a microstrip reflectarray compared to the conventional parabolic reflector. The scan performance of the reflect arrays was found to improve with f/D ratios as is true for paraboloids. In general, scanning by means of displaced feed is limited to a few beam - widths in reflectarrays. Feed displacement in the axial direction of a symmetric reflectarray was investigated and compared to that of paraboloids. The gain loss due to the defocused feed of a reflectarray was found to be nearly the same as that of a paraboloid of the same subtended angle for larger values of f/D, and for displacements away from the antenna. The gain loss of an axially defocused reflectarray was found to be

  13. a 40 GHZ Planar Array Antenna Using Hybrid Coupling

    NASA Astrophysics Data System (ADS)

    van der Wilt, F. P.; Strijbos, J. H. M.

    A new linearly polarized microstrip patch array is presented. The array is fed by using a combination of aperture coupling from a slotted waveguide and coplanar feeding using series-fed patch arrays. Advantages of this so-called hybrid coupling are easy control of the illumination of the array and a low feed loss, since the number of microstrip lines is kept to the minimum. In the paper we discuss how to design a Hybrid Coupled Planar Array (HCPA) antenna by using CAD modeling. Furthermore, we discuss several more features of the antenna type, such as its reasonable bandwidth, low cross-polarization and constructional simplicity. A 40 GHz 120-element HCPA antenna with a broadside beam has been built and tested. Experimental results for this array are presented.

  14. Imaging antenna arrays

    NASA Technical Reports Server (NTRS)

    Rutledge, D. B.; Muha, M. S.

    1982-01-01

    Many millimeter and far-infrared imaging systems are limited in sensitivity and speed because they depend on a single scanned element. Because of recent advances in planar detectors such as Schottky diodes, superconducting tunnel junctions, and microbolometers, an attractive approach to this problem is a planar antenna array with integrated detectors. A planar line antenna array and optical system for imaging has been developed. The significant advances are a 'reverse-microscope' optical configuration and a modified bow-tie antenna design. In the 'reverse-microscope' configuration, a lens is attached to the bottom of the substrate containing the antennas. Imaging is done through the substrate. This configuration eliminates the troublesome effects of substrate surface waves. The substrate lens has only a single refracting surface, making possible a virtually aplanatic system, with little spherical aberration or coma. The array is characterized by an optical transfer function that is easily measured. An array with 19 dB crosstalk levels between adjacent antennas has been tested and it was found that the array captured 50 percent of the available power. This imaging system was diffraction limited.

  15. An antenna-coupled bolometer with an integrated microstrip bandpass filter

    NASA Astrophysics Data System (ADS)

    Myers, Michael J.; Holzapfel, William; Lee, Adrian T.; O'Brient, Roger; Richards, P. L.; Tran, Huan T.; Ade, Peter; Engargiola, Greg; Smith, Andy; Spieler, Helmuth

    2005-03-01

    We describe the fabrication and testing of antenna-coupled superconducting transition-edge bolometers for use at millimeter wavelengths. The design uses a double-slot dipole antenna connected to superconducting niobium microstrip. Band defining filters are implemented in the microstrip, which is then terminated with a load resistor. The power dissipated in the load resistor is measured by a superconducting transition-edge sensor (TES). The load resistor and TES are thermally well connected and are supported by a silicon nitride substrate. The substrate is suspended by four narrow silicon nitride legs for thermal isolation. The bolometers have been optically characterized and the spectral response is presented. This detector is a prototype element for use in an array designed for studies of the cosmic microwave background polarization.

  16. Antenna-coupled bolometer arrays using transition-edgesensors

    SciTech Connect

    Myers, Michael J.; Ade, Peter; Engargiola, Greg; Holzapfel,William; Lee,Adrian T.; O'Brient, Roger; Richards, Paul L.; Smith, Andy; Spieler, Helmuth; Tran, Huan

    2004-06-08

    We describe the development of an antenna-coupled bolometer array for use in a Cosmic Microwave Background polarization experiment. Prototype single pixels using double-slot dipole antennas and integrated microstrip band defining filters have been built and tested. Preliminary results of optical testing and simulations are presented. A bolometer array design based on this pixel will also be shown and future plans for application of the technology will be discussed.

  17. Microstrip antenna modeling and measurement at high frequencies

    SciTech Connect

    Bevensee, R.M.

    1986-04-30

    This report addresses the task C(i) of the Proposal for Microstrip Antenna Modeling and Measurement at High Frequencies by the writer, July 1985. The task is: Assess the advantages and disadvantages of the three computational approaches outlined in the Proposal, including any difficulties to be resolved and an estimate of the time required to implement each approach. The three approaches are (1) Finite Difference, (2) Sommerfeld-GTD-MOM, and (3) Surface Intergral Equations - MOM. These are discussed in turn.

  18. Arbitrarily oriented biaxially anisotropic media: Wave behavior and microstrip antennas

    NASA Astrophysics Data System (ADS)

    Graham, Jennifer Warzala

    This dissertation explores the electromagnetic behavior of arbitrarily oriented biaxially anisotropic media. An overview of wave behavior in biaxially anisotropic (or simply biaxial) media is presented. The reflection and transmission behaviors of electromagnetic waves from half-space and two-layer isotropic-biaxial interfaces are studied. The reflection and transmission coefficients are used in the formulation of eigenvector dyadic Green's functions. These Green's functions are employed in full-wave analyses of rectangular microstrip antennas printed on biaxial substrates. The general characteristics of electrically biaxially anisotropic (biaxial) media are presented including permittivity tensors, optic axes, orientation of the medium, and birefringence. After a detailed discussion of wave propagation, wave behavior at isotropic-biaxial interfaces is investigated. The reflection and transmission of electromagnetic waves incident upon half-space and two-layer interfaces, at which the waves may be incident from either the isotropic region or the biaxial region, are investigated. The biaxial medium considered may be aligned with the principal coordinate system or may be arbitrarily oriented. Critical angle and Brewster angle effects are analyzed for the half-space case. Once the wave behavior is well understood, the eigenvector dyadic Green's function is presented for two-layer geometries involving isotropic and biaxially anisotropic media. The symmetrical property of the dyadic Green's function is derived and used to generate an unknown Green's function from a known Green's function for the two-layer geometry of interest. This new Green's function is used to model rectangular microstrip antennas. Following the investigation of reflection and transmission, rectangular microstrip antennas are analyzed using the eigenvector dyadic Green's function and the method of moments. Galerkin's method is used to evaluate current distributions on gap-fed dipole antennas and

  19. Radiation Pattern of Chair Armed Microstrip Antenna

    NASA Astrophysics Data System (ADS)

    Mishra, Rabindra Kishore; Sahu, Kumar Satyabrat

    2016-07-01

    This work analyzes planar antenna conformable to chair arm shaped surfaces for WLAN application. Closed form expressions for its radiation pattern are developed and validated using measurements on prototype and commercial EM code at 2.4 GHz.

  20. An experimental investigation of high temperature superconducting microstrip antennas at K- and Ka-band frequencies. Ph.D. Thesis Final Report

    NASA Technical Reports Server (NTRS)

    Richard, Mark A.

    1993-01-01

    The recent discovery of high temperature superconductors (HTS) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS results in narrow bandwidths and high patch edge impedances of such antennas. To investigate the performance of superconducting microstrip antennas, three antenna architectures at K and Ka-band frequencies are examined. Superconducting microstrip antennas that are directly coupled, gap coupled, and electromagnetically coupled to a microstrip transmission line were designed and fabricated on lanthanum aluminate substrates using YBa2Cu3O7 superconducting thin films. For each architecture, a single patch antenna and a four element array were fabricated. Measurements from these antennas, including input impedance, bandwidth, patterns, efficiency, and gain are presented. The measured results show usable antennas can be constructed using any of the architectures. All architectures show excellent gain characteristics, with less than 2 dB of total loss in the four element arrays. Although the direct and gap coupled antennas are the simplest antennas to design and fabricate, they suffer from narrow bandwidths. The electromagnetically coupled antenna, on the other hand, allows the flexibility of using a low permittivity substrate for the patch radiator, while using HTS for the feed network, thus increasing the bandwidth while effectively utilizing the low loss properties of HTS. Each antenna investigated in this research is the first of its kind reported.

  1. The development of inflatable array antennas

    NASA Technical Reports Server (NTRS)

    Huang, J.

    2001-01-01

    Inflatable array antennas are being developed to significantly reduce the mass, the launch vehicle's stowage volume, and the cost of future spacecraft systems. Three inflatable array antennas, recently developed for spacecraft applications, are a 3.3 m x 1.0 m L-band synthetic-aperture radar (SAR) array, a 1.0 m-diameter X-band telecom reflectarray, and a 3 m-diameter Ka-band telecom reflectarray. All three antennas are similar in construction, and each consists of an inflatable tubular frame that supports and tensions a multi-layer thin-membrane RF radiating surface with printed microstrip patches. The L-band SAR array achieved a bandwidth of 80 MHz, an aperture efficiency of 74%, and a total mass of 15 kg. The X-band reflectarray achieved an aperture efficiency of 37%, good radiation patterns, and a total mass of 1.2 kg (excluding the inflation system). The 3 m Ka-band reflectarray achieved a surface flatness of 0.1 mm RMS, good radiation patterns, and a total mass of 12.8 kg (excluding the inflation system). These antennas demonstrated that inflatable arrays are feasible across the microwave and millimeter-wave spectrums. Further developments of these antennas are deemed necessary, in particular, in the area of qualifying the inflatable structures for space-environment usage.

  2. A compact annular ring microstrip antenna for WSN applications.

    PubMed

    Wang, Daihua; Song, Linli; Zhou, Hanchang; Zhang, Zhijie

    2012-01-01

    A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN) application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna's performance of a steel installation base. By using a chip resistor of large resistance (120 Ω) the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and -2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels. PMID:23012510

  3. A Compact Annular Ring Microstrip Antenna for WSN Applications

    PubMed Central

    Wang, Daihua; Song, Linli; Zhou, Hanchang; Zhang, Zhijie

    2012-01-01

    A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN) application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna's performance of a steel installation base. By using a chip resistor of large resistance (120 Ω) the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and –2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels. PMID:23012510

  4. Antenna array research

    NASA Technical Reports Server (NTRS)

    Tai, C.

    1973-01-01

    Antenna array research on electromagnetic field problems in inhomogeneous media is presented along with characteristics of the Eaton lens. Comparisons are given of the radiation pattern and directivity of small Luneburg lens with a homogeneous lens. References and figure captions on radiation patterns are included.

  5. Microstrip dipole antennas on electrically thick substrates

    NASA Astrophysics Data System (ADS)

    Jackson, D. R.; Alexopoulos, N. G.

    1985-10-01

    Printed circuit antennas are attractive radiation sources both at microwave and millimeter wave frequencies. However, for millimeter wave applications where the substrate is likely to be electrically thick, it is important to understand the basic effects of a thick substrate on radiation characteristics. In particular, it is concluded here that dipole radiation properties become sensitive to loss as the substrate becomes thick. Furthermore, the efficiency of dipoles on thick substrates tends to be low, especially as the dielectric constant of the substrate increases. A method of improving both the efficiency and gain can be used for thick substrates, however, which uses a superstrate layer on top of the antenna.

  6. Development of a microstrip UHF conformal antenna

    NASA Technical Reports Server (NTRS)

    Shields, M. W.; Cassell, R. B.

    1977-01-01

    Low profile, engineering model EMU antennas were constructed. Final data for these antennas meet most of the electrical requirements in a 6 in. x 18 in. x 1.4 in. package which weighs under 2.0 lbs. Coverage data calculated at the design frequencies very nearly meets the design goal of providing a gain greater than or equal to -10 dBi over 80% of a sphere. Recommendations are made for future work directed toward producing an efficient quality design capable of operating in a space environment.

  7. Electrically Small Microstrip Quarter-Wave Monopole Antennas

    NASA Technical Reports Server (NTRS)

    Young, W. Robert

    2004-01-01

    Microstrip-patch-style antennas that generate monopole radiation patterns similar to those of quarter-wave whip antennas can be designed to have dimensions smaller than those needed heretofore for this purpose, by taking advantage of a feed configuration different from the conventional one. The large sizes necessitated by the conventional feed configuration have, until now, made such antennas impractical for frequencies below about 800 MHz: for example, at 200 MHz, the conventional feed configuration necessitates a patch diameter of about 8 ft (.2.4 m) . too large, for example, for mounting on the roof of an automobile or on a small or medium-size aircraft. By making it possible to reduce diameters to between a tenth and a third of that necessitated by the conventional feed configuration, the modified configuration makes it possible to install such antennas in places where they could not previously be installed and thereby helps to realize the potential advantages (concealment and/or reduction of aerodynamic drag) of microstrip versus whip antennas. In both the conventional approach and the innovative approach, a microstrip-patch (or microstrip-patch-style) antenna for generating a monopole radiation pattern includes an electrically conductive patch or plate separated from an electrically conductive ground plane by a layer of electrically insulating material. In the conventional approach, the electrically insulating layer is typically a printed-circuit board about 1/16 in. (.1.6 mm) thick. Ordinarily, a coaxial cable from a transmitter, receiver, or transceiver is attached at the center on the ground-plane side, the shield of the cable being electrically connected to the ground plane. In the conventional approach, the coaxial cable is mated with a connector mounted on the ground plane. The center pin of this connector connects to the center of the coaxial cable and passes through a hole in the ground plane and a small hole in the insulating layer and then connects

  8. Compact, Lightweight Dual-Frequency Microstrip Antenna Feed for Future Soil Moisture and Sea Surface Salinity Missions

    NASA Technical Reports Server (NTRS)

    Yueh, Simon; Wilson, William J.; Njoku, Eni; Dinardo, Steve; Hunter, Don; Rahmat-Samii, Yahya; Kona, Keerti S.; Manteghi, Majid

    2006-01-01

    The development of a compact, lightweight, dual-frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described. The design is based on the microstrip stacked-patch array (MSPA) to be used to feed a large lightweight deployable rotating mesh antenna for spaceborne L-band (approx.1 GHz) passive and active sensing systems. The design features will also enable applications to airborne soil moisture and salinity remote sensing sensors operating on small aircrafts. This paper describes the design of stacked patch elements and 16-element array configuration. The results from the return loss, antenna pattern measurements and sky tests are also described.

  9. Magnetic field probe for measuring surface current distributions on millimetre wave microstrip antennas

    NASA Astrophysics Data System (ADS)

    Grzybowski, R. R.; Bansal, R.

    1991-01-01

    A magnetic field probe for measuring surface current distributions on millimeter wave microstrip antennas has been designed and fabricated. This current probe was tested by measuring the surface current distributions of printed microstrip dipole antennas. The current distributions obtained compared well with the theoretically expected distributions.

  10. Transformation of design formulae for feed line of triangular microstrip antenna

    NASA Astrophysics Data System (ADS)

    Mathur, Monika; Singh, Ghanshyam; Bhatnagar, S. K.; Swami, Swati; Vats, Abhijat

    2016-03-01

    In wireless communication system microstrip antenna is the key component. Popular shapes of patch for microstrip are rectangular, triangular and circular. A new transformation design formulae for feed line of rectangular microstrip antenna by using equivalent design concept were presented by the authors. That says one designed antenna for a given frequency on any substrate can be transformed into another substrate material for the same design frequency by simply multiply a factor ψ to the all dimensions of patch, length of feed line and some power of ψ for feed line width (where ψ is the square root of the ratio of dielectric constants of those two designs). This paper presents that the same formulae of that rectangular transformation feed line can also be applicable for triangular shape microstrip antenna transformation. The process was repeated for the triangular shape patch microstrip antenna as applied for rectangular shape and the simulation results were surprisingly the same for it by applying the same transformation formulae.

  11. MSAT vehicular antennas with self scanning array elements

    NASA Technical Reports Server (NTRS)

    Shafai, L.

    1990-01-01

    A new approach for designing low profile antennas for MSAT applications is presented. It is based on stacking two microstrip antennas that operate at two adjacent modes. The beam scanning is achieved by introducing a phase shift between the stacked elements and consequently a low cost self scan array element is developed. The concept is used to investigate two different antenna types: (1) a single element unit, with its phase shifter, that provides a moderate gain of about 7 dBic; and (2) a seven element array with a peak gain of about 14 dBic. Computed and measured data for each design are presented and discussed.

  12. Detection mechanisms in microstrip dipole antenna-coupled infrared detectors

    NASA Astrophysics Data System (ADS)

    Codreanu, Iulian; Gonzalez, Francisco J.; Boreman, Glenn D.

    2003-06-01

    We compare the detection mechanisms employed in microstrip dipole antenna-coupled infrared detectors. The electrical currents induced along the antenna arms are detected by a rectangular niobium (Nb) microsensor placed at the center of the antenna. The ohmic nature of the Au-Nb contact determines the detection mechanism. Devices with linear contacts between the Au antenna arms and the Nb microsensor exhibit bolometric response. A nonlinear Au-insulator-Nb junction rectifies the induced antenna currents. Devices with nonlinear contacts also exhibit a bolometric response. The devices with nonlinear contacts are 1/ f noise limited while the devices with linear contacts are Johnson noise limited. The rectification mechanism is 5.3 times faster than the thermal detection. The current-voltage ( I- V) characteristic of the devices exhibiting bolometric response is linear, while that of the rectifying devices is cubic. For devices with nonlinear contacts excellent agreement is obtained between the measured detector response and the ratio between the second and the first derivative of the I- V characteristic.

  13. Ferroelectric/Semiconductor Tunable Microstrip Patch Antenna Developed

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2001-01-01

    A lithographically printed microwave antenna that can be switched and tuned has been developed. The structure consists of a rectangular metallic "patch" radiator patterned on a thin ferroelectric film that was grown on high-resistivity silicon. Such an antenna may one day enable a single-phased array aperture to transmit and receive signals at different frequencies, or it may provide a simple way to reconfigure fractal arrays for communications and radar applications.

  14. [Microstrip antenna design and system research of radio frequency identification temperature sensor].

    PubMed

    Yang, Hao; Yang, Xiaohe; Chen, Yuquan; Pan, Min

    2008-12-01

    Radio frequency identification sensor network, which is a product of integrating radio frequency identification (RFID) with wireless sensor network (WSN), is introduced in this paper. The principle of radio frequency identification sensor is analyzed, and the importance of the antenna is emphasized. Then three kinds of common antennae, namely coil antenna, dipole antenna and microstrip antenna, are discussed. Subsequently, according to requirement, we have designed a microstrip antenna in a wireless temperature-monitoring and controlling system. The measurement of factual effect showed the requirement was fulfilled. PMID:19166222

  15. Design of a 4-element Antenna Array for BDS Anti-jamming Applications

    NASA Astrophysics Data System (ADS)

    Li, Jianxing; Shi, Hongyu; Li, Hang; Zhang, Anxue

    2014-01-01

    In this paper, a compact 4-element antenna array with the dimension of 150 mm × 150 mm is proposed for BeiDou navigation satellite system (BDS) anti-jamming applications. The proposed antenna array comprises of four identical microstrip right-handed circularly polarized (RHCP) antenna elements. The four microstrip antenna elements are placed in the same polarity with a distance of 80 mm between adjacent elements. The antenna element which employs dual probe-fed structure has a relatively small volume of 45 mm × 45 mm × 5 mm. The antenna array has been fabricated and measured. The experimental results show that the proposed antenna array is quite suitable for BDS anti-jamming application.

  16. Antenna-coupled TES bolometer arrays for CMB polarimetry

    NASA Astrophysics Data System (ADS)

    Kuo, C. L.; Bock, J. J.; Bonetti, J. A.; Brevik, J.; Chattopadhyay, G.; Day, P. K.; Golwala, S.; Kenyon, M.; Lange, A. E.; LeDuc, H. G.; Nguyen, H.; Ogburn, R. W.; Orlando, A.; Transgrud, A.; Turner, A.; Wang, G.; Zmuidzinas, J.

    2008-07-01

    We describe the design and performance of polarization selective antenna-coupled TES arrays that will be used in several upcoming Cosmic Microwave Background (CMB) experiments: SPIDER, BICEP-2/SPUD. The fully lithographic polarimeter arrays utilize planar phased-antennas for collimation (F/4 beam) and microstrip filters for band definition (25% bandwidth). These devices demonstrate high optical efficiency, excellent beam shapes, and well-defined spectral bands. The dual-polarization antennas provide well-matched beams and low cross polarization response, both important for high-fidelity polarization measurements. These devices have so far been developed for the 100 GHz and 150 GHz bands, two premier millimeter-wave atmospheric windows for CMB observations. In the near future, the flexible microstrip-coupled architecture can provide photon noise-limited detection for the entire frequency range of the CMBPOL mission. This paper is a summary of the progress we have made since the 2006 SPIE meeting in Orlando, FL.

  17. Reconfigurable Wideband Circularly Polarized Microstrip Patch Antenna for Wireless Applications

    NASA Astrophysics Data System (ADS)

    Khidre, Ahmed

    In this thesis, developments of rectangular microstrip patch antenna to have circular polarization agility with wideband performance, for wireless applications are presented. First, a new technique to achieve circularly polarized (CP) probe feed single-layer microstrip patch antenna with wideband characteristics is proposed. The antenna is a modified form of the popular E-shaped patch, used to broaden the impedance bandwidth of a basic rectangular patch antenna. This is established by letting the two parallel slots of the E-patch unequal. Thus, by introducing asymmetry two orthogonal currents on the patch are excited and circularly polarized fields are realized. The proposed technique exhibits the advantage of the simplicity inherent in the E-shaped patch design. It requires only slot lengths, widths, and position parameters to be determined. Also, it is suitable for later adding the reconfigurable capability. With the aid of full-wave simulator Ansoft HFSS, investigations on the effect of various dimensions of the antenna have been carried out via parametric analysis. Based on these investigations, a design procedure for a CP E-shaped patch is summarized. Various design examples with different substrate thicknesses and material types are presented and compared, with CP U-slot patch antennas, recently proposed in the literature. A prototype has been constructed following the suggested design procedure to cover the IEEE 802.11b/g WLAN band. The performance of the fabricated antenna was measured and compared with the simulation results for the reflection coefficient, axial ratio, radiation pattern, and antenna gain. Good agreement is achieved between simulation and measured results demonstrating a high gain and wideband performance. Second, a polarization reconfigurable single feed E-shaped patch antenna with wideband performance is proposed. The antenna is capable of switching from right-hand circular polarization (RHCP) to left-hand circular polarization (LHCP) and

  18. 1x2 Array of U-Slotted Rectangular Patch Antennas for HighSpeed LTE Mobile Networks

    NASA Astrophysics Data System (ADS)

    Daud, P.; H, Sri.; Mahmudin, D.; Estu, T. T.; Fathnan, A. A.; Wijayanto, Y. N.; Armi, N.

    2016-01-01

    Microstrip antenna is a shaped thin board of antenna and capable for working at high frequencies. Microstrip antenna has a pattern strip shape in a various form, one of which is a rectangular shape. Microstrip antennas have some shortcomings which have narrow bandwidth and small gain, to cover the shortfall, the antenna is made using an array to increase the gain and u - slot to widen the bandwidth. In this paper will discuss the results of the antenna simulation using Ansoft HFSS software applications and their compliance with specifications designed antenna. In this issues we analysis the results of the design and simulation microstrip antenna at a frequency of 2.6 - 2.7 GHz for LTE applications

  19. Design considerations for rectangular microstrip patch antenna on electromagnetic crystal substrate at terahertz frequency

    NASA Astrophysics Data System (ADS)

    Singh, G.

    2010-01-01

    The effects of 2-D electromagnetic crystal substrate on the performance of a rectangular microstrip patch antennas at THz frequencies is simulated. Electromagnetic crystal substrate is used to obtain extremely broad-bandwidth with multi-frequency band operation of the proposed microstrip antennas. Multi-frequency band microstrip patch antennas are used in modern communication systems in order to enhance their capacity through frequency reuse. The simulated 10 dB impedance bandwidth of the rectangular patch microstrip antenna is 34.3% at THz frequency (0.6-0.95 THz). The radiation efficiency, gain and directivity of the proposed antenna are presented at different THz frequencies. The simulation has been performed using CST Microwave Studio, which is a commercially available electromagnetic simulator based on finite integral technique.

  20. Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics.

    PubMed

    Kuwahara, D; Ito, N; Nagayama, Y; Yoshinaga, T; Yamaguchi, S; Yoshikawa, M; Kohagura, J; Sugito, S; Kogi, Y; Mase, A

    2014-11-01

    A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array. PMID:25430218

  1. Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics

    SciTech Connect

    Kuwahara, D.; Ito, N.; Nagayama, Y.; Yoshinaga, T.; Yamaguchi, S.; Yoshikawa, M.; Kohagura, J.; Sugito, S.; Kogi, Y.; Mase, A.

    2014-11-15

    A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

  2. Radiation patterns of dual concentric conductor microstrip antennas for superficial hyperthermia.

    PubMed

    Stauffer, P R; Rossetto, F; Leoncini, M; Gentilli, G B

    1998-05-01

    The finite difference time domain (FDTD) method has been used to calculate electromagnetic radiation patterns from 915-MHz dual concentric conductor (DCC) microwave antennas that are constructed from thin and flexible printed circuit board (PCB) materials. Radiated field distributions are calculated in homogeneous lossy muscle tissue loads located under variable thickness coupling bolus layers. This effort extends the results of previous investigations to consider more realistic applicator configurations with smaller 2-cm-square apertures and different coupling bolus materials and thicknesses, as well as various spacings of multiple-element arrays. Results are given for practical applicator designs with microstrip feedlines etched on the backside of the PCB antenna array instead of previously tested bulky coaxial-cable feedline connections to each radiating aperture. The results demonstrate that for an optimum coupling bolus thickness of 2.5-5 mm, the thin, flexible, and lightweight DCC antennas produce effective heating to the periphery of each aperture to a depth of approximately 1 cm, and may be combined into arrays for uniform heating of large area superficial tissue regions with the 50% power deposition contour conforming closely to the outer perimeter of the array. PMID:9581059

  3. Planar array antenna for ERS-1 synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Wagner, R.

    1986-08-01

    To meet ERS-1 SAR specifications as to high gain, very narrow beamwidth in azimuth, and a slightly tapered shaped beam in elevation, a long narrow antenna was designed. At 5.3 GHz center frequency, the slotted waveguide antenna concept was selected over the reflector or the microstrip principles. Reasons are the low losses, good beamshaping capability, and mechanical compactness. A resonant array is chosen. All waveguides are made from metallized CFRP for reasons of low mass. The mechanical antenna system features a deployable configuration, plus the associated mechanisms. The performance verification concept, through analyses, and tests at different levels, is described.

  4. A new analysis for the transmission line characteristics of the Microstrip Dipole Antenna Feed

    NASA Astrophysics Data System (ADS)

    Sabhnani, N. H.; Rao, B. V.

    1983-10-01

    The characteristic wave impedance and effective dielectric constant of a Microstrip Dipole Antenna Feed are evaluated through a conformal mapping technique. The obtained design equations are explicit, simple and yield results with an accuracy better than 2.2 percent.

  5. Stripline feed for a microstrip array of patch elements with teardrop shaped probes

    NASA Technical Reports Server (NTRS)

    Huang, John (Inventor)

    1989-01-01

    A circularly polarized microstrip array antenna utilizing a honeycomb substrate made of dielectric material to support on one side the microstrip patch elements in an array, and on the other side a stripline circuit for feeding the patch elements in subarray groups of four with angular orientation and phase for producing circularly polarized radiation, preferably at a 0, 90, 180, and 270 degree relationship is described. The probe used for coupling each feed point in the stripline circuit to a microstrip patch element is teardrop shaped in order to introduce capacitance between the coupling probe and the metal sheet of the stripline circuit that serves as an antenna ground plane. The capacitance thus introduced tunes out inductance of the probe. The shape of the teardrop probe is not critical. The probe capacitance required is controlled by the maximum diameter for the teardrop shaped probe, which can be empirically determined for the operating frequency. An aluminum baffle around each subarray blocks out surface wave between subarrays.

  6. Stripline feed for a microstrip array of patch elements with teardrop shaped probes

    NASA Technical Reports Server (NTRS)

    Huang, John (Inventor)

    1990-01-01

    A circularly polarized microstrip array antenna utilizing a honeycomb substrate made of dielectric material to support on one side the microstrip patch elements in an array, and on the other side a stripline circuit for feeding the patch elements in subarray groups of four with angular orientation and phase for producing circularly polarized radiation, preferably at a 0.degree., 90.degree., 180.degree. and 270.degree. relationship. The probe used for coupling each feed point in the stripline circuit to a microstrip patch element is teardrop shaped in order to introduce capacitance between the coupling probe and the metal sheet of the stripline circuit that serves as an antenna ground plane. The capacitance thus introduced tunes out inductance of the probe. The shape of the teardrop probe is not critical. The probe capacitance required is controlled by the maximum diameter for the teardrop shaped probe, which can be empirically determined for the operating frequency. An aluminum baffle around each subarray blocks out surface waves between subarrays.

  7. Planar Microstrip Yagi Array with Notched Parasitic Elements

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Zaman, Afoz J.

    2001-01-01

    The design and radiation characteristics of a planar microstrip Yagi array with notched parasitic elements are presented. Results indicate that a directional beam 45 deg from the broadside direction with a gain over 7 dB can be achieved. Good agreements were observed between experimental and analytical results.

  8. BI-ground microstrip array coil vs. conventional microstrip array coil for mouse imaging at 7 tesla

    NASA Astrophysics Data System (ADS)

    Hernández, Ricardo; Terrones, M. A. López; Jakob, P. M.

    2012-10-01

    At high field strengths, the need for more efficient high frequency coils has grown. Since the radiation losses and the interaction between coil and sample increase proportionally to field strength, the quality factor (Q) and the sensitivity of the coil decrease as consequence of these negative effects. Since Zhang et al proposed in 2001 a new surface coil based on the microstrip transmission line for high frequency, different Tx-Rx phased arrays based on this concept have been already introduced in animal and whole body systems at high field strengths, each of them with different modifications in order to get better field homogeneity, SNR or isolation between coil elements in the array. All these arrays for animals systems have been built for rat imaging. One of these modifications is called BI-Ground Microstrip Array Coil (BIGMAC). The implementation of a smaller two-channel BIGMAC design for mouse imaging is studied and its performance compared to a two-channel conventional Microstrip array at 7 Tesla, the higher isolation by using BIGMAC elements in comparison with conventional Microstrip elements is shown in this work.

  9. Wideband microstrip dipole

    NASA Astrophysics Data System (ADS)

    Dey, Supriyo; Aanandan, C. K.; Jose, K. A.; Mohanan, P.; Nair, K. G.

    1992-12-01

    A new wideband half-wave microstrip dipole antenna is described which operates in low-frequency range with more than 5 percent 2:1 VSWR bandwidth. The design is based on a stripline feeding mechanism to prevent radiation from the feeding structure and on proper end-loading of dipole arms to enhance the impedance bandwidth. It is concluded that this dipole can replace the conventional dipoles or existing microstrip antennas in phased array application.

  10. Electronic switching spherical array antenna

    NASA Technical Reports Server (NTRS)

    Stockton, R.

    1978-01-01

    This work was conducted to demonstrate the performance levels attainable with an ESSA (Electronic Switching Spherical Array) antenna by designing and testing an engineering model. The antenna was designed to satisfy general spacecraft environmental requirements and built to provide electronically commandable beam pointing capability throughout a hemisphere. Constant gain and beam shape throughout large volumetric coverage regions are the principle characteristics. The model is intended to be a prototype of a standard communications and data handling antenna for user scientific spacecraft with the Tracking and Data Relay Satellite System (TDRSS). Some additional testing was conducted to determine the feasibility of an integrated TDRSS and GPS (Global Positioning System) antenna system.

  11. JPL Large Advanced Antenna Station Array Study

    NASA Technical Reports Server (NTRS)

    1978-01-01

    In accordance with study requirements, two antennas are described: a 30 meter standard antenna and a 34 meter modified antenna, along with a candidate array configuration for each. Modified antenna trade analyses are summarized, risks analyzed, costs presented, and a final antenna array configuration recommendation made.

  12. A Dual Polarization, Active, Microstrip Antenna for an Orbital Imaging Radar System Operating at L-Band

    NASA Technical Reports Server (NTRS)

    Kelly, Kenneth C.; Huang, John

    2000-01-01

    A highly successful Earth orbiting synthetic antenna aperture radar (SAR) system, known as the SIR-C mission, was carried into orbit in 1994 on a U.S. Shuttle (Space Transportation System) mission. The radar system was mounted in the cargo bay with no need to fold, or in any other way reduce the size of the antennas for launch. Weight and size were not limited for the L-Band, C-Band, and X-Band radar systems of the SIR-C radar imaging mission; the set of antennas weighed 10,500 kg, the L-Band antenna having the major share of the weight. This paper treats designing an L-Band antenna functionally similar to that used for SIR-C, but at a fraction of the cost and at a weight in the order of 250 kg. Further, the antenna must be folded to fit into the small payload shroud of low cost booster rocket systems. Over 31 square meters of antenna area is required. This low weight, foldable, electronic scanning antenna is for the proposed LightSAR radar system which is to be placed in Earth orbit on a small, dedicated space craft at the lowest possible cost for an efficient L- Band radar imaging system. This LightSAR spacecraft radar is to be continuously available for at least five operational years, and have the ability to map or repeat-map any area on earth within a few days of any request. A microstrip patch array, with microstrip transmission lines heavily employed in the aperture and in the corporate feed network, was chosen as the low cost approach for this active dual-polarization, 80 MHz (6.4%) bandwidth antenna design.

  13. A Dual Polarization, Active, Microstrip Antenna for an Orbital Imaging Radar System Operating at L-Band

    NASA Technical Reports Server (NTRS)

    Kelly, Kenneth C.; Huang, John

    1999-01-01

    A highly successful Earth orbiting synthetic antenna aperture radar (SAR) system, known as the SIR-C mission, was carried into orbit in 1994 on a U.S. Shuttle (Space Transportation System) mission. The radar system was mounted in the cargo bay with no need to fold, or in any other way reduce the size of the antennas for launch. Weight and size were not limited for the L-Band, C-Band, and X-Band radar systems of the SIR-C radar imaging mission; the set of antennas weighed 10,500 kg, the L-Band antenna having the major share of the weight. This paper treats designing an L-Band antenna functionally similar to that used for SIR-C, but at a fraction of the cost and at a weight in the order of 250 kg. Further, the antenna must be folded to fit into the small payload shroud of low cost booster rocket systems. Over 31 square meters of antenna area is required. This low weight, foldable, electronic scanning antenna is for the proposed LightSAR radar system which is to be placed in Earth orbit on a small, dedicated space craft at the lowest possible cost for an efficient L-Band radar imaging system. This LightSAR spacecraft radar is to be continuously available for at least five operational years, and have the ability to map or repeat-map any area on earth within a few days of any request. A microstrip patch array, with microstrip transmission lines heavily employed in the aperture and in the corporate feed network, was chosen as the low cost approach for this active dual-polarization, 80 MHz (6.4%) bandwidth antenna design.

  14. Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application

    PubMed Central

    Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

    2016-01-01

    Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software—High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication. PMID:27355954

  15. Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application.

    PubMed

    Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

    2016-01-01

    Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software-High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication. PMID:27355954

  16. Suspended Rectangular/Circular Patch Antennas with Electromagnetically Coupled Inverted Microstrip Feed for Dual Polarization/Frequency

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2000-01-01

    The paper demonstrates suspended rectangular and circular patch antennas with electromagnetically coupled inverted microstrip feed for linear as well as dual linear polarization/frequency applications. The measured results include the return loss and the impedance bandwidth of the antennas.

  17. Ultra-wideband miniaturized microstrip patch antennas for wireless communications: Design guidelines and modeling

    NASA Astrophysics Data System (ADS)

    Dandu, Varun Kumar

    The number of wireless communication applications continue to increase steadily, leading to competition for currently allocated frequency bands. Capacity issues in form of data rate and latency have always been a bottleneck for broadband wireless-communication usage. New communication systems like ultra-wideband (UWB) require larger bandwidth than what is normally utilized with traditional antenna techniques. The interest for compact consumer electronics is growing in the meantime, creating a demand on efficient and low profile antennas which can be integrated on a printed circuit board. The main objective of this thesis is to study, design, analyze and implement UWB low profile microstrip patch antenna that satisfy UWB technology requirements. Some methods to extend the bandwidth and other antenna parameters associated with wideband usages are studied. Several techniques are used for optimal UWB bandwidth performance of the UWB microstrip patch antenna. The performance parameters such as VSWR, Gain and radiation pattern of the UWB microstrip patch antenna is extensively investigated with simulations using FEKO. A set of simple design guidelines is proposed to provide approximate rules that result in optimum "first-pass" designs of probe-fed, miniaturized, low profile, microstrip UWB antennas using different bandwidth-enhancement techniques to satisfy UWB bandwidth that require minimal tuning.

  18. Infinite phased array of microstrip dipoles in two layers

    NASA Astrophysics Data System (ADS)

    Castaneda, Jesus A.

    1989-01-01

    A method has been devised for the analysis of the infinite printed strip dipole array in a two layer microstrip substrate structure. The complete dynamic Green's function appropriate to the two-layer substrate-superstrate structure was used in the formulation of the method of moments solution. In this way all the substrate effects, including the surface wave related phenomena, have been included in the development and solution. The solution provides a means by which the most important performance characteristics of the finite-but-large phase-scanned microstrip array can be studied. Attention has been focused on the characterization of the active input impedance as a function of the equivalent scan angle.

  19. Microstrip antenna study for Pioneer Saturn/Uranus atmosphere entry probe

    NASA Technical Reports Server (NTRS)

    Kuhlman, E. A.

    1974-01-01

    The design parameters of a microstrip antenna were studied to determine its performance characteristics as affected by an atmospheric entry probe environment. The technical literature was reviewed to identify the known design and performance characteristics. These data were used to evaluate the expected effects of mission environments on the microstrip antenna design proposed for the Saturn/Uranus Atmospheric Entry Probe (SAEP). Radiation patterns and VSWR measurements were made to evaluate the performance in the SAEP thermal environment. Results of the literature search and pattern tests confirm that the microstrip antenna is a good choice as a transmitting antenna on the SAEP. The microstrip antenna is efficient, compact, and well suited to a space environment. The pattern can be controlled with a minimum beamwidth of 60 degrees (air substrate; e.g., honeycomb structure) and a maximum on the order of 100 degrees with higher dielectric constant substrates. The power handling capacity is good and can be improved by covering the antenna with a dielectric cover.

  20. Inflatable Microstrip Reflectarray Antennas At X and Ka-Band Frequencies

    NASA Technical Reports Server (NTRS)

    Huang, John; Feria, Alfonso

    1998-01-01

    Introduction: Inflatable antenna technology is being developed by JPL/NASA to enable the capabilities of low mass, high packaging efficiency, and low-cost deployment for future spacecraft high-gain and large aperture antennas. One of the technologies being considered [11 is the inflatable microstrip reflectarray. A conventional inflatable parabolic reflector antenna will offer similar advantages with the added capability of wide electrical bandwidth. However, it suffers from the difficulty of maintaining its required large, thin, and curved-parabolic surface in the space environment. Since the microstrip reflectarray has the "natural" flat reflecting surface, it is much easier to maintain the required surface tolerance using an inflatable structure. This is the primary reason, despite its narrow bandwidth characteristic, that the inflatable microstrip reflectarray is being studied. This article discusses an already-developed one-meter X-band inflatable microstrip reflectarray and a three-meter Ka-band inflatable microstrip reflectarray which is currently under development. Both antennas' RF structures are designed at JPL and their mechanical inflatable structures are designed and manufactured at ILC Dover, Inc.

  1. Inflatable Microstrip Reflectarray Antennas at X and Ka-band Frequencies

    NASA Technical Reports Server (NTRS)

    Huang, John; Feria, Alfonso

    1999-01-01

    Inflatable antenna technology is being developed by JPL/NASA to enable the capabilities of low mass, high packaging efficiency, and low-cost deployment for future spacecraft high-gain and large aperture antennas. One of the technologies being considered is the inflatable microstrip reflectarray. A conventional inflatable parabolic reflector antenna will offer similar advantages with the added capability of wide electrical bandwidth. However, it suffers from the difficulty of maintaining its required large, thin, and curved-parabolic surface in the space environment. Since the microstrip reflectarray has the "natural" flat reflecting surface, it is much easier to maintain the required surface tolerance using an inflatable structure. This is the primary reason, despite its narrow bandwidth characteristic, that the inflatable microstrip reflectarray is being studied. This article discusses an already-developed one-meter X-band inflatable microstrip reflectarray and a three-meter Ka-band inflatable microstrip reflectarray which is currently under development. Both antennas' RF structures are designed at JPL and their mechanical inflatable structures are designed and manufactured at ILC Dover, Inc.

  2. Evaluation of the Reflection Coefficient of Microstrip Elements for Reflectarray Antennas

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam

    2011-01-01

    Basis functions were studied and identified that provide efficient and accurate solutions for the induced patch currents and the reflection phase in microstrip reflect arrays. The integral equation of an infinite array of microstrip elements in the form of patches or crossed dipoles excited by a uniform plane wave is solved by the method-of-moments. Efficient choices of entire domain basis functions that yield accurate results have been described.

  3. The design of microstrip dipole arrays including mutual coupling. I Theory. II - Experiment

    NASA Astrophysics Data System (ADS)

    Elliott, R. S.; Stern, G. J.

    1981-09-01

    A design technique which includes mutual coupling is formulated for use with microstrip dipole arrays. The technique is based on iterative solution of a combined design equation and requires as input foreknowledge of the self-impedances and mutual impedances of microstrip dipoles and also the link between the radiating current and the backscattered wave in the feeding line. Procedures for obtaining the input design data for microstrip dipole arrays are then described and the design of a typical array is presented. The design data indicate that mutual coupling is a significant factor which cannot be ignored in the design of small microstrip dipole arrays.

  4. View north of the antenna array, note the communications antenna ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View north of the antenna array, note the communications antenna in the middleground - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Four Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  5. Multibeam Phased Array Antennas

    NASA Technical Reports Server (NTRS)

    Popovic, Zoya; Romisch, Stefania; Rondineau, Sebastien

    2004-01-01

    In this study, a new architecture for Ka-band multi-beam arrays was developed and demonstrated experimentally. The goal of the investigation was to demonstrate a new architecture that has the potential of reducing the cost as compared to standard expensive phased array technology. The goals of this specific part of the project, as stated in the yearly statement of work in the original proposal are: 1. Investigate bounds on performance of multi-beam lens arrays in terms of beamwidths, volume (size), isolation between beams, number of simultaneous beams, etc. 2. Design a small-scale array to demonstrate the principle. The array will be designed for operation around 3OGHz (Ka-band), with two 10-degree beamwidth beams. 3. Investigate most appropriate way to accomplish fine-tuning of the beam pointing within 5 degrees around the main beam pointing angle.

  6. Effect of Weaving Direction of Conductive Yarns on Electromagnetic Performance of 3D Integrated Microstrip Antenna

    NASA Astrophysics Data System (ADS)

    Xu, Fujun; Yao, Lan; Zhao, Da; Jiang, Muwen; Qiu, Yipping

    2013-10-01

    A three-dimensionally integrated microstrip antenna (3DIMA) is a microstrip antenna woven into the three-dimensional woven composite for load bearing while functioning as an antenna. In this study, the effect of weaving direction of conductive yarns on electromagnetic performance of 3DIMAs are investigated by designing, simulating and experimental testing of two microstrip antennas with different weaving directions of conductive yarns: one has the conductive yarns along the antenna feeding direction (3DIMA-Exp1) and the other has the conductive yarns perpendicular the antenna feeding direction (3DIMA-Exp2). The measured voltage standing wave ratio (VSWR) of 3DIMA-Exp1 was 1.4 at the resonant frequencies of 1.39 GHz; while that of 3DIMA-Exp2 was 1.2 at the resonant frequencies of 1.35 GHz. In addition, the measured radiation pattern of the 3DIMA-Exp1 has smaller back lobe and higher gain value than those of the 3DIMA-Exp2. This result indicates that the waving direction of conductive yarns may have a significant impact on electromagnetic performance of textile structural antennas.

  7. A K-Band Linear Phased Array Antenna Based on Ba(0.60)Sr(0.40)TiO3 Thin Film Phase Shifters

    NASA Technical Reports Server (NTRS)

    Romanofsky, R.; Bernhard, J.; Washington, G.; VanKeuls, F.; Miranda, F.; Cannedy, C.

    2000-01-01

    This paper summarizes the development of a 23.675 GHz linear 16-element scanning phased array antenna based on thin ferroelectric film coupled microstripline phase shifters and microstrip patch radiators.

  8. Influence of dielectric substrate on the responsivity of microstrip dipole-antenna-coupled infrared microbolometers

    NASA Astrophysics Data System (ADS)

    Codreanu, Iulian; Boreman, Glenn D.

    2002-04-01

    We report on the influence of the dielectric substrate on the performance of microstrip dipole-antenna-coupled microbolometers. The location, the width, and the magnitude of the resonance of a printed dipole are altered when the dielectric substrate is backed by a ground plane. A thicker dielectric substrate shifts the antenna resonance toward shorter dipole lengths and leads to a stronger and slower detector response. The incorporation of an air layer into the antenna substrate further increases thermal impedance, leading to an even stronger response and shifting the antenna resonance toward longer dipole lengths.

  9. Influence of dielectric substrate on the responsivity of microstrip dipole-antenna-coupled infrared microbolometers.

    PubMed

    Codreanu, Iulian; Boreman, Glenn D

    2002-04-01

    We report on the influence of the dielectric substrate on the performance of microstrip dipole-antenna-coupled microbolometers. The location, the width, and the magnitude of the resonance of a printed dipole are altered when the dielectric substrate is backed by a ground plane. A thicker dielectric substrate shifts the antenna resonance toward shorter dipole lengths and leads to a stronger and slower detector response. The incorporation of an air layer into the antenna substrate further increases thermal impedance, leading to an even stronger response and shifting the antenna resonance toward longer dipole lengths. PMID:11936778

  10. Influence of solar heating on the performance of integrated solar cell microstrip patch antennas

    SciTech Connect

    Roo-Ons, M.J.; Shynu, S.V.; Ammann, M.J.; Seredynski, M.; McCormack, S.J.; Norton, B.

    2010-09-15

    The integration of microstrip patch antennas with photovoltaics has been proposed for applications in autonomous wireless communication systems located on building facades. Full integration was achieved using polycrystalline silicon solar cells as both antenna ground plane and direct current power generation in the same device. An overview of the proposed photovoltaic antenna designs is provided and the variation characterised of the electromagnetic properties of the device with temperature and solar radiation. Measurements for both copper and solar antennas are reported on three different commercial laminates with contrasting values for thermal coefficient of the dielectric constant. (author)

  11. A Stacked Microstrip Patch Antenna Loaded With U-Shaped Slots

    NASA Astrophysics Data System (ADS)

    Tiwari, Harshvardhan; Kartikeyan, Machavazam V.

    2011-07-01

    In this work, an extensive design study of a stacked U-slot microstrip patch antenna for dual band operation will be presented. This antenna consists of two stacked microstrip patches, both having U-slots embedded in them. Two feeding techniques namely probe-feeding and co-planar waveguide feeding have been used and the results compared. The antennas were simulated using CST Microwave Studio's Transient Solver which is based on the Finite Integral Technique (FIT) and particle swarm optimization was used to optimize the antenna parameters for both the cases. The simulated and measured results indicate that using co-planar waveguide feeding results in a tremendous increase in bandwidth when compared with probe feeding, however degradation in gain is observed.

  12. Coplanar waveguide feeds for phased array antennas

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1992-01-01

    The design and performance of the following coplanar waveguide (CPW) microwave distribution networks for linear as well as circularly polarized microstrip patches and printed dipole arrays is presented: (1) CPW/microstrip line feed; (2) CPW/balanced stripline feed; (3) CPW/slotline feed; (4) grounded CPW (GCPW)/balanced coplanar stripline feed; and (5) CPW/slot coupled feed. Typical measured radiation patterns are presented, and their relative advantages and disadvantages are compared.

  13. Coplanar waveguide feeds for phased array antennas

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1991-01-01

    The design and performance is presented of the following coplanar waveguides (CPW) microwave distribution networks for linear as well as circularly polarized microstrip patches and dipole arrays: (1) CPW/microstrip line feed; (2) CPW/balanced stripline feed; (3) CPW/slotline feed; (4) grounded CPW/balanced coplanar stripline feed; and (5) CPW/slot coupled feed. Typical measured radiation patterns are presented, and their relative advantages and disadvantages are compared.

  14. Coplanar waveguide feeds for phased array antennas

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1991-01-01

    The design and performance is presented of the following Coplanar Waveguides (CPW) microwave distribution networks for linear as well as circularly polarized microstrip patches and dipole arrays: (1) CPW/Microstrip Line feed; (2) CPW/Balanced Stripline feed; (3) CPW/Slotline feed; (4) Grounded CPW/Balanced coplanar stripline feed; and (5) CPW/Slot coupled feed. Typical measured radiation patterns are presented, and their relative advantages and disadvantages are compared.

  15. Coplanar waveguide feeds for phased array antennas

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Lee, Richard Q.

    1991-09-01

    The design and performance is presented of the following coplanar waveguides (CPW) microwave distribution networks for linear as well as circularly polarized microstrip patches and dipole arrays: (1) CPW/microstrip line feed; (2) CPW/balanced stripline feed; (3) CPW/slotline feed; (4) grounded CPW/balanced coplanar stripline feed; and (5) CPW/slot coupled feed. Typical measured radiation patterns are presented, and their relative advantages and disadvantages are compared.

  16. Coplanar waveguide feeds for phased array antennas

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Lee, Richard Q.

    1992-08-01

    The design and performance of the following coplanar waveguide (CPW) microwave distribution networks for linear as well as circularly polarized microstrip patches and printed dipole arrays is presented: (1) CPW/microstrip line feed; (2) CPW/balanced stripline feed; (3) CPW/slotline feed; (4) grounded CPW (GCPW)/balanced coplanar stripline feed; and (5) CPW/slot coupled feed. Typical measured radiation patterns are presented, and their relative advantages and disadvantages are compared.

  17. Coplanar waveguide feeds for phased array antennas

    NASA Astrophysics Data System (ADS)

    Simons, Rainee N.; Lee, Richard Q.

    1991-09-01

    The design and performance is presented of the following Coplanar Waveguides (CPW) microwave distribution networks for linear as well as circularly polarized microstrip patches and dipole arrays: (1) CPW/Microstrip Line feed; (2) CPW/Balanced Stripline feed; (3) CPW/Slotline feed; (4) Grounded CPW/Balanced coplanar stripline feed; and (5) CPW/Slot coupled feed. Typical measured radiation patterns are presented, and their relative advantages and disadvantages are compared.

  18. Effective side length formula for resonant frequency of equilateral triangular microstrip antenna

    NASA Astrophysics Data System (ADS)

    Guney, Kerim; Kurt, Erhan

    2016-02-01

    A novel and accurate expression is obtained by employing the differential evolution algorithm for the effective side length (ESL) of the equilateral triangular microstrip antenna (ETMA). This useful formula allows the antenna engineers to accurately calculate the ESL of the ETMA. The computed resonant frequencies (RFs) show very good agreement with the experimental RFs when this accurate ESL formula is utilised for the computation of the RFs for the first five modes.

  19. Interleaved array antenna technology development

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This is the third phase of a program to establish an antenna concept for shuttle and free flying spacecraft earth resources experiments using Synthetic Aperture Radar. The feasibility of a plated graphite epoxy waveguide for a space antenna was evaluated. A quantity of flat panels and waveguides were developed, procured, and tested for electrical and mechanical properties. In addition, processes for the assembly of a unique waveguide array were investigated. Finally, trades between various configurations that would allow elevation (range) electronic scanning and that would minimize feed complexity for various RF bandwidths were made.

  20. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-03-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S11) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  1. Hybrid perturbation scheme for wide beamwidth circularly polarized stacked patch microstrip antenna for satellite communication

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Shakawat

    Circularly polarized microstrip antennas are popular for satellite communications due to their circularly polarized orientation. They are used frequently in modern day satellite communication. In order to achieve wide angular coverage in satellite communication, a wide beamwidth is required from the antenna. Traditional single layer microstrip antenna inherently demonstrates low angular beamwidth of approximately 600 to 800and thereby lacks wide angular coverage when used for satellite communication. The objective of this thesis is to design a single-fed stacked microstrip antenna using different perturbation techniques in order to achieve a wide angular beamwidth. This thesis presents a new design for a circularly polarized antenna based on the hybrid perturbation scheme. First, a method of stacked patch-ring with negative perturbation was used to generate a significantly larger beamwidth of 1060. The axial ratio (AR) bandwidth obtained is also significantly larger compared to the case when square rings are used as parasitic and driven rings with a single feed. A simulated impedance bandwidth (S11< - 10 dB) of 16%, 3 dB AR bandwidth of 8% and a peak gain of 8.65 dBic are obtained from this design. Next, a new design of stacked hybrid antenna is presented, which uses hybrid perturbations to generate circular polarization radiation. An enhanced beamwidth of 1260 was obtained. The simulation results are confirmed by the measured results.

  2. Monolithic microwave integrated circuit devices for active array antennas

    NASA Technical Reports Server (NTRS)

    Mittra, R.

    1984-01-01

    Two different aspects of active antenna array design were investigated. The transition between monolithic microwave integrated circuits and rectangular waveguides was studied along with crosstalk in multiconductor transmission lines. The boundary value problem associated with a discontinuity in a microstrip line is formulated. This entailed, as a first step, the derivation of the propagating as well as evanescent modes of a microstrip line. The solution is derived to a simple discontinuity problem: change in width of the center strip. As for the multiconductor transmission line problem. A computer algorithm was developed for computing the crosstalk noise from the signal to the sense lines. The computation is based on the assumption that these lines are terminated in passive loads.

  3. Time-delayed directional beam phased array antenna

    DOEpatents

    Fund, Douglas Eugene; Cable, John William; Cecil, Tony Myron

    2004-10-19

    An antenna comprising a phased array of quadrifilar helix or other multifilar antenna elements and a time-delaying feed network adapted to feed the elements. The feed network can employ a plurality of coaxial cables that physically bridge a microstrip feed circuitry to feed power signals to the elements. The cables provide an incremental time delay which is related to their physical lengths, such that replacing cables having a first set of lengths with cables having a second set of lengths functions to change the time delay and shift or steer the antenna's main beam. Alternatively, the coaxial cables may be replaced with a programmable signal processor unit adapted to introduce the time delay using signal processing techniques applied to the power signals.

  4. Mutual coupling between microstrip dipoles in multielement arrays

    NASA Astrophysics Data System (ADS)

    Katehi, Pisti B.

    1989-03-01

    An analytical method for evaluating mutual coupling in multielement microstrip arrays is discussed. The elements of the array are strip dipoles covered by an overlayer and excited by microstrip lines embedded in the substrate. In addition, two different ways of excitation are considered to evaluate the effect of the feeding lines on the coupling between the dipoles. Throughout the analysis, the transmission line and dipole widths are taken to be a fraction of the free-space wavelength, so that the longitudinal current component is the dominant contributor to the characteristics of the array. Under this assumption, the transverse component of the current is neglected without introducing appreciable error. The current distribution along the longitudinal direction is evaluated by solving an appropriate integral equation using Galerkin's method with piecewise continuous sinusoidal functions. All possible interactions between the currents on the feeding transmission lines and dipoles are included. The method is valid in the microwave and millimeter-wave range and accounts for conductor thickness and surface wave excitation.

  5. Input impedance of a probe-fed circular microstrip antenna with thick substrate

    NASA Technical Reports Server (NTRS)

    Davidovitz, M.; Lo, Y. T.

    1986-01-01

    A method of computing the input impedance for the probe fed circular microstrip antenna with thick dielectric substrate is presented. Utilizing the framework of the cavity model, the fields under the microstrip patch are expanded in a set of modes satisfying the boundary conditions on the eccentrically located probe, as well as on the cavity magnetic wall. A mode-matching technique is used to solve for the electric field at the junction between the cavity and the coaxial feed cable. The reflection coefficient of the transverse electromagnetic (TEM) mode incident in the coaxial cable is determined, from which the input impedance of the antenna is computed. Measured data are presented to verify the theoretical calculations. Results of the computation of various losses for the circular printed antenna as a function of substrate thickness are also included.

  6. A planar broad-band flared microstrip slot antenna

    NASA Astrophysics Data System (ADS)

    Povinelli, Mark J.

    1987-08-01

    Experimental results have been obtained on a planar multioctave bandwidth flared microstrip slot. When crossed, the element is capable of horizontal, vertical, or circular polarization. A design was fabricated and measurements were taken to define the performance. The input impedance and radiation characteristics are shown to have a broad-band response when configured as a cavity-backed element.

  7. On the modeling of electromagnetically coupled microstrip antennas - The printed strip dipole

    NASA Astrophysics Data System (ADS)

    Katehi, P. B.; Alexopoulos, N. G.

    1984-11-01

    A generalized solution for a class of printed circuit antennas excited by a strip transmission line is presented. The strip transmission line may be embedded inside or printed on the substrate. As an example, microstrip dipoles electromagnetically coupled (parasitically excited) to embedded strip transmission line have been analyzed accurately, and design graphs are provided for a specific substrate material. These graphs permit the establishment of a design procedure which yields the microstrip dipole length, overlap, offset, and substrate thickness with the goal of a desired input match for a given substrate material. The method accounts for conductor thickness and for arbitrary substrate parameters. Comparison with experiment shows excellent agreement.

  8. On the modeling of electromagnetically coupled microstrip antennas: The printed strip dipole

    NASA Astrophysics Data System (ADS)

    Katehi, P. B.; Alexopoulos, N. G.

    1984-04-01

    A generalized solution for a class of printed circuit antennas, excited by a strip transmission line is presented. The strip transmission line may be embedded inside or printed on the substrate. As an example, microstrip dipoles electromagnetically coupled (parasitically excited) to embedded strip transmission line have been analyzed accurately and design graphs are provided for a specific substrate material. These graphs permit the establishment of a design procedure which yields the microstrip dipole length, overlap, offset, and substrate thickness with the goal of a desired input match for a given substrate material. The method accounts for conductor thickness and for arbitrary substrate parameters. Comparison with experiment shows excellent agreement.

  9. Analysis of a slot loaded microstrip disk antenna for circular polarisation

    NASA Technical Reports Server (NTRS)

    Rao, Y. R.; Deshpande, Manohar D.

    1991-01-01

    A method is presented to analyze a circular microstrip disk antenna loaded with a narrow, inclined slot at its center and fed by a coaxial probe. Making use of the exact dyadic Green's functions for a grounded dielectric slab due to electric and magnetic currents, Richmond's reaction integral equation in conjunction with the method of moments (Galerkin), a generalized h-parameter equivalent network for the loaded patch is obtained. An expression for the input impedance of a slot loaded microstrip patch is obtained from the equivalent parameters. The theoretical results are compared with the experiment.

  10. Design and performance of a 4.5GHz circularly polarized YBa 2Cu 3O 7 microstrip antenna

    NASA Astrophysics Data System (ADS)

    Zhu, M. H.; Cao, B. S.; Zhang, X. X.; Li, W. H.; Yuan, H. J.; Wang, Y. J.; Zhang, L. W.; Dong, D. J.; Liu, M. L.; Cui, D. F.; He, M.; Zhou, Y. L.; Liu, T. J.

    1997-08-01

    A 4.5GHz circularly polarized YBCO microstrip antenna was designed and fabricated. Measurements showed that at 77K the superconducting antenna had about 3dB gain improvement over the comparable silver antenna, in agreement with the calculated results using the modified Green function method.

  11. Bandwidth optimization of compact microstrip antenna for PCS/DCS/bluetooth application

    NASA Astrophysics Data System (ADS)

    Singh, Vinod; Ali, Zakir; Ayub, Shahanaz; Singh, Ashutosh

    2014-09-01

    A novel compact broadband microstrip patch antenna is presented for various wireless applications. The proposed antenna has been fabricated and the impedance bandwidth and radiation pattern are measured. The simulated and measured antenna characteristics along with radiation pattern and gain are presented. It is stated that the proposed designed antenna can completely cover the required band widths of Digital communication system (DCS 1.71-1.88 GHz), Personal communication system (PCS 1.85-1.88 GHz) and IEEE 802.11b/g (2.4-2.485 GHz) with satisfactory radiation characteristics. The Experimental result shows that the proposed antenna presents a bandwidth 60.25% covering the range of 1.431-2.665 GHz with the maximum radiation efficiency 90%.

  12. Compact double-p slotted inset-fed microstrip patch antenna on high dielectric substrate.

    PubMed

    Ahsan, M R; Islam, M T; Habib Ullah, M; Mahadi, W N L; Latef, T A

    2014-01-01

    This paper presents a compact sized inset-fed rectangular microstrip patch antenna embedded with double-P slots. The proposed antenna has been designed and fabricated on ceramic-PTFE composite material substrate of high dielectric constant value. The measurement results from the fabricated prototype of the antenna show -10 dB reflection coefficient bandwidths of 200 MHz and 300 MHz with center resonant frequency of 1.5 GHz and 4 GHz, respectively. The fabricated antenna has attained gains of 3.52 dBi with 81% radiation efficiency and 5.72 dBi with 87% radiation efficiency for lower band and upper band, respectively. The measured E- and H-plane radiation patterns are also presented for better understanding. Good agreement between the simulation and measurement results and consistent radiation patterns make the proposed antenna suitable for GPS and C-band applications. PMID:25165750

  13. Parallel and series FED microstrip array with high efficiency and low cross polarization

    NASA Technical Reports Server (NTRS)

    Huang, John (Inventor)

    1995-01-01

    A microstrip array antenna for vertically polarized fan beam (approximately 2 deg x 50 deg) for C-band SAR applications with a physical area of 1.7 m by 0.17 m comprises two rows of patch elements and employs a parallel feed to left- and right-half sections of the rows. Each section is divided into two segments that are fed in parallel with the elements in each segment fed in series through matched transmission lines for high efficiency. The inboard section has half the number of patch elements of the outboard section, and the outboard sections, which have tapered distribution with identical transmission line sections, terminated with half wavelength long open-circuit stubs so that the remaining energy is reflected and radiated in phase. The elements of the two inboard segments of the two left- and right-half sections are provided with tapered transmission lines from element to element for uniform power distribution over the central third of the entire array antenna. The two rows of array elements are excited at opposite patch feed locations with opposite (180 deg difference) phases for reduced cross-polarization.

  14. A phased array tracking antenna for vehicles

    NASA Technical Reports Server (NTRS)

    Ohmori, Shingo; Mano, Kazukiko; Tanaka, Kenji; Matsunaga, Makoto; Tsuchiya, Makio

    1990-01-01

    An antenna system including antenna elements and a satellite tracking method is considered a key technology in implementing land mobile satellite communications. In the early stage of land mobile satellite communications, a mechanical tracking antenna system is considered the best candidate for vehicles, however, a phased array antenna will replace it in the near future, because it has many attractive advantages such as a low and compact profile, high speed tracking, and potential low cost. Communications Research Laboratory is now developing a new phased array antenna system for land vehicles based on research experiences of the airborne phased array antenna, which was developed and evaluated in satellite communication experiments using the ETS-V satellite. The basic characteristics of the phased array antenna for land vehicles are described.

  15. Bandwidth Enhancement of a Dual Band Planar Monopole Antenna Using Meandered Microstrip Feeding

    PubMed Central

    Ahsan, M. R.; Islam, M. T.; Habib Ullah, M.; Misran, N.

    2014-01-01

    A meandered-microstrip fed circular shaped monopole antenna loaded with vertical slots on a high dielectric material substrate (εr = 15) is proposed in this paper. The performance criteria of the proposed antenna have been experimentally verified by fabricating a printed prototype. The experimental results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing meandered-microstrip feeding in assistant of partial ground plane. It is observed that, the −10 dB impedance bandwidth of the proposed antenna at lower band is 44.4% (600 MHz–1 GHz) and at upper band is 28% (2.25 GHz–2.95 GHz). The measured maximum gains of −1.18 dBi and 4.87 dBi with maximum radiation efficiencies have been observed at lower band and upper band, respectively. The antenna configuration and parametric study have been carried out with the help of commercially available computer-aided EM simulator, and a good accordance is perceived in between the simulated and measured results. The analysis of performance criteria and almost consistent radiation pattern make the proposed antenna a suitable candidate for UHF RFID, WiMAX, and WLAN applications. PMID:24723832

  16. Bandwidth enhancement of a dual band planar monopole antenna using meandered microstrip feeding.

    PubMed

    Ahsan, M R; Islam, M T; Habib Ullah, M; Misran, N

    2014-01-01

    A meandered-microstrip fed circular shaped monopole antenna loaded with vertical slots on a high dielectric material substrate (ε r = 15) is proposed in this paper. The performance criteria of the proposed antenna have been experimentally verified by fabricating a printed prototype. The experimental results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing meandered-microstrip feeding in assistant of partial ground plane. It is observed that, the -10 dB impedance bandwidth of the proposed antenna at lower band is 44.4% (600 MHz-1 GHz) and at upper band is 28% (2.25 GHz-2.95 GHz). The measured maximum gains of -1.18 dBi and 4.87 dBi with maximum radiation efficiencies have been observed at lower band and upper band, respectively. The antenna configuration and parametric study have been carried out with the help of commercially available computer-aided EM simulator, and a good accordance is perceived in between the simulated and measured results. The analysis of performance criteria and almost consistent radiation pattern make the proposed antenna a suitable candidate for UHF RFID, WiMAX, and WLAN applications. PMID:24723832

  17. Tri-band microstrip antenna design for wireless communication applications

    NASA Astrophysics Data System (ADS)

    Sami, Gehan; Mohanna, Mahmoud; Rabeh, Mohamed L.

    2013-06-01

    This paper introduces a novel rectangular tri-band patch antenna that is fabricated and measured for wireless communication systems. The introduced antenna is designed for WLAN and WiMAX applications. The desired tri-band operation was obtained by proper loading for a rectangular patch antenna using slots and shorting pins. The optimal location and dimension for the loaded elements were obtained with the aid of interfacing a Genetic Algorithm (GA) model with an Ansoft High Frequency Structural Simulator (HFSS). The results obtained from our simulated antenna show 5.8% impedance matching band width at 2.4 GHz, 3.7% at 3.5 GHz and 1.57% at 5.7 GHz. In addition, an equivalent circuit of the proposed antenna is introduced using the least square curve fitting optimization technique.

  18. Quality Factor Effect on the Wireless Range of Microstrip Patch Antenna Strain Sensors

    PubMed Central

    Daliri, Ali; Galehdar, Amir; Rowe, Wayne S. T.; John, Sabu; Wang, Chun H.; Ghorbani, Kamran

    2014-01-01

    Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace and civil industries. However, the wireless interrogation range of these sensors is limited to few centimeters, which restricts their practical application. This paper presents an investigation on the effect of circular microstrip patch antenna (CMPA) design on the quality factor and the maximum practical wireless reading range of the sensor. The results reveal that by using appropriate substrate materials the interrogation distance of the CMPA sensor can be increased four-fold, from the previously reported 5 to 20 cm, thus improving considerably the viability of this type of wireless sensors for strain measurement and damage detection. PMID:24451457

  19. Quality factor effect on the wireless range of microstrip patch antenna strain sensors.

    PubMed

    Daliri, Ali; Galehdar, Amir; Rowe, Wayne S T; John, Sabu; Wang, Chun H; Ghorbani, Kamran

    2014-01-01

    Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace and civil industries. However, the wireless interrogation range of these sensors is limited to few centimeters, which restricts their practical application. This paper presents an investigation on the effect of circular microstrip patch antenna (CMPA) design on the quality factor and the maximum practical wireless reading range of the sensor. The results reveal that by using appropriate substrate materials the interrogation distance of the CMPA sensor can be increased four-fold, from the previously reported 5 to 20 cm, thus improving considerably the viability of this type of wireless sensors for strain measurement and damage detection. PMID:24451457

  20. Estimation of Resonant Frequency of a Circular Microstrip Antenna Using Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Singh, Jagtar; Singh, A. P.; Kamal, T. S.

    2012-03-01

    In recent years the art of using artificial neural networks for wireless communication engineers has been gaining momentum. In this paper a general procedure is suggested for estimating the resonant frequency of circular microstrip patch antenna using artificial neural networks. The method of moments (MOM) based IE3D software was used to generate data dictionary for training and validation set of ANN. The proposed technique uses multilayer feed-forward back-propagation artificial neural network with one hidden layers for estimating the resonant frequency of a circular microstrip antenna. A relative performance of the different training algorithms is carried out for estimating the resonant frequency with particular attention paid to the speed of computation and accuracy achieved. This type of performance comparison has not been attempted so far.

  1. The finite ground plane effect on the microstrip antenna radiation patterns

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1983-01-01

    The uniform geometrical theory of diffraction (GTD) is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip antenna. The source field from the radiating patch is calculated by two different methods: the slot theory and the modal expansion theory. Many numerical and measured results are presented to demonstrate the accuracy of the calculations and the finite ground plane edge effect.

  2. Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings

    NASA Astrophysics Data System (ADS)

    Rivera-Albino, Alix

    Global Positioning System (GPS) is a navigation system widely used in civilian and military application, but its accuracy is highly impacted with consequential fading, and possible loss of communication due to multipath propagation and high power interferences. This dissertation proposes alternatives to improve the performance of the GPS receivers to obtain a system that can be reliable in critical situations. The basic performance of the GPS receiver consists of receiving the signal with an antenna array, delaying the signal at each antenna element, weighting the delayed replicas, and finally, combining the weighted replicas to estimate the desired signal. Based on these, three modifications are proposed to improve the performance of the system. The first proposed modification is the use of the Least Mean Squares (LMS) algorithm with two variations to decrease the convergence time of the classic LMS while achieving good system stability. The results obtained by the proposed LMS demonstrate that the algorithm can achieve the same stability as the classic LMS using a small step size, and its convergence rate is better than the classic LMS using a large step size. The second proposed modification is to replace the uniform distribution of the time delays (or taps) by an exponential distribution that decreases the bit-error rate (BER) of the system without impacting the computational efficiency of the uniform taps. The results show that, for a BER of 0.001, the system can operate with a 1 to 2 dB lower signal-to-noise ratio (SNR) when an exponential distribution is used rather than a uniform distribution. Finally, the third modification is implemented in the design of the antenna array. In this case, the gain of each microstrip element is enhanced by embedding ferrite rings in the substrate, creating a hybrid substrate. The ferrite rings generates constructive interference between the incident and reflected fields; consequently, the gain of a single microstrip element

  3. 10 GHz Microstrip Spanar Antennas: An Experimental Analysis

    NASA Astrophysics Data System (ADS)

    Azlishah Othman, Mohd; Azman, Hazwani; Nor Husain, Mohd; Zoinol Abidin Abd Aziz, Mohamad; Abd Rahim, Yahaya; Nairn Che Pee, Ahmad; Radzi Motsidi, Mohamad; Fairuz Iskandar Othman, Mohd

    2014-04-01

    This paper presents Spanar Antenna designed using CST Microwave Studio Simulation 2011. The proposed antenna was designed to operate at 10 GHz, which suggested return loss, S11 must be less than -10 dB and voltage standing wave ratio (VSWR) must be less than 2. The best performance of simulation of Spanar Antenna was obtained at a small size of 24.8 mm × 8.0 mm with dimension board of FR4 substrate 31.7 mm × 18.5 mm. The thickness (h) and dielectric constant (ɛr) of substrate were 1.6 mm and 4.7. An analysis between simulation result and measurement result has been compared in order to see the antenna performance.

  4. Pressure and shear sensing based on microstrip antennas

    NASA Astrophysics Data System (ADS)

    Mohammad, I.; Huang, H.

    2012-04-01

    A foot ulcer is the initiating factor in 85% of all diabetic amputations. Ulcer formation is believed to be contributed by both pressure and shear forces. There are commercially available instruments that can measure plantar pressure. However, instruments for plantar shear measurement are limited. In this paper, we investigate the application of antenna sensors for shear and pressure measurement. The principle of operation of both antenna sensors will be discussed first, followed by detailed descriptions on the antenna designs, sensor fabrication, experimental setup, procedure and results. Because the antenna sensors are small in size, can be wirelessly interrogated, and are frequency multiplexable, we plan to embed them in shoes for simultaneous mapping of plantar shear and pressure distributions in the future.

  5. New carbon nanotube antenna array simulation and fabrication

    NASA Astrophysics Data System (ADS)

    Zareie, Hosein; Davoudzadeh, Nima; Koohsorkhi, Javad; Mohajerzadeh, Shamsoddin; Rouhi, Nima

    2009-03-01

    A novel THz antenna structure, made of carbon nanotube arrays is suggested. Using CST MICROWAVE STUDIO (CST MWS), the capabilities of carbon nanotube terahertz (THz) antenna arrays have been simulated and this CNT antenna array has been fabricated.

  6. Resonance spectra of diabolo optical antenna arrays

    NASA Astrophysics Data System (ADS)

    Guo, Hong; Simpkins, Blake; Caldwell, Joshua D.; Guo, Junpeng

    2015-10-01

    A complete set of diabolo optical antenna arrays with different waist widths and periods was fabricated on a sapphire substrate by using a standard e-beam lithography and lift-off process. Fabricated diabolo optical antenna arrays were characterized by measuring the transmittance and reflectance with a microscope-coupled FTIR spectrometer. It was found experimentally that reducing the waist width significantly shifts the resonance to longer wavelength and narrowing the waist of the antennas is more effective than increasing the period of the array for tuning the resonance wavelength. Also it is found that the magnetic field enhancement near the antenna waist is correlated to the shift of the resonance wavelength.

  7. Resonance spectra of diabolo optical antenna arrays

    SciTech Connect

    Guo, Hong; Guo, Junpeng; Simpkins, Blake; Caldwell, Joshua D.

    2015-10-15

    A complete set of diabolo optical antenna arrays with different waist widths and periods was fabricated on a sapphire substrate by using a standard e-beam lithography and lift-off process. Fabricated diabolo optical antenna arrays were characterized by measuring the transmittance and reflectance with a microscope-coupled FTIR spectrometer. It was found experimentally that reducing the waist width significantly shifts the resonance to longer wavelength and narrowing the waist of the antennas is more effective than increasing the period of the array for tuning the resonance wavelength. Also it is found that the magnetic field enhancement near the antenna waist is correlated to the shift of the resonance wavelength.

  8. A printed circuit cylindrical array antenna

    NASA Astrophysics Data System (ADS)

    Agrawal, Ashok K.; Powell, Walter E.

    1986-11-01

    The design and performance of a Ku-band cylindrical antenna are described. The antenna is designed to provide a 360-deg azimuth coverage with 20-dB sidelobes and an operating bandwidth of 1 GHz (16.0-17.0 GHz). The antenna consists of 16 facets of 2 x 4 dipole arrays. The 360-deg coverage is obtained with a switch matrix network. The antenna elements and the feeding switch matrix network are printed on a single printed circuit board.

  9. Design and fabrication of low-cost reconfigurable microstrip antenna using photodiode as optical switching

    NASA Astrophysics Data System (ADS)

    Kusumawati, E. R.; Pramono, Y. H.; Rubiyanto, A.

    2014-09-01

    Design, fabrication, and characterization prototype of reconfigurable dipole microstrip antenna using photodiode as optical switching have been conducted in the Laboratory for Optical and Microwave Physics Department Faculty of ITS. This paper presents a new reconfigurable antenna design using photodiode as optical switching. In order to be optical switching, photodiode must be illuminated by optical source. The optical source used is Infrared with power 8 mW. Antenna is fabricated in FR-4 substrate which has 1.6 mm thick and 4.8 relative permittivity value. The dimension of the substrate is 131 mm × 21.5 mm × 1.6 mm. The structure of antenna is Coplanar Stripline (CPS) dipole. Measurement is conducted in two state. First state is photodiodes unilluminated Infrared and the second state is illuminated. The measurement result indicate that if condition is not illuminated by Infrared (OFF-state) antenna has resonance frequency of 2010 MHz and 2120 MHz. At frequency 2010 MHz, S11 value -35.7 dB and bandwidth 57 MHz, meanwhile at frequency 2120 MHz, S11 value -17.3 dB and bandwidth 42 MHz. Then if photodiode was illuminated by infrared (ON-state), antenna work at frequency 2007 MHz with S11 value -41.8 dB and bandwidth 61 MHz and 2113 MHz with S11 value -19.4 and bandwidth 47 MHz. There was frequency shifting from 2010 MHz to 2007 MHz and 2120 MHz to 2113 MHz of 5 MHz. At ON state, S11 value also was shifting. There was 6.1 dB and 2.1 dB. Bandwidth at ON-state is wider than OFF state. Microstrip antenna with a reconfigurable optical switching photodiode has several advantages. The advantages are more easily fabricated and the cost is relatively cheaper than the other techniques of optical switching.

  10. A Dual Polarized Ultra-Wideband Slot Antenna Using Stepped Microstrip Feed Structure

    NASA Astrophysics Data System (ADS)

    Ram Krishna, R. V. S.; Kumar, Raj

    2015-11-01

    In this paper, a printed slot antenna for ultra-wideband dual polarization is proposed and experimentally demonstrated. The slot is L-shape and its two arms are individually microstrip fed for producing the orthogonal polarizations. The slot arms and the microstrip feed lines are step sectioned for wideband impedance matching. For isolation purpose, a slant narrow metallic stub is inserted at the junction of the slot arms. The antenna has an impedance bandwidth of 118% (3.1-12 GHz) and isolation of around 20 dB over most of the band. The radiation patterns are nearly omnidirectional with a peak gain varying from 3 to 6 dBi. For assessing the diversity performance of the antenna, the envelope correlation coefficients are computed from the simulated and measured S-parameters and found to be within acceptable limits. With a compact, single substrate design, the antenna is expected to be useful for printed circuit ultra wideband applications requiring dual polarization features.

  11. Dielectric parameter estimation of novel magneto-dielectric substrate based microstrip antenna

    NASA Astrophysics Data System (ADS)

    Saini, Ashish; Kumar, P.; Ravelo, B.; Thakur, Atul; Thakur, Preeti

    2016-05-01

    The effective relative permittivity and effective relative permeability of magneto-dielectric materials when used as substrate for microstrip antenna shows interdependency. This dependency was analyzed through simulation and verified by synthesizing nano composite ferrite. The 40nm nano crystallite size particles were synthesized using a co- precipitation method. Matching values of complex permittivity (ɛ* = 4.2-0.1j) and complex permeability (μ* = 4.3-0.2j) at 1 GHz were obtained from the electromagnetic characterization. The microstrip antenna with coaxial feed was fabricated and the interdependence of relative permittivity and relative permeability was verified. An error of 7% in the drawn length was observed for ɛr and μr of the order of 4. The magneto-dielectric material with composition Mn0.5Zn0.3Co0.2Fe2O4+BaFe12O19 proposed in this paper definitely can be proposed as a substrate material for miniaturized antenna. The antenna with desired resonant frequency can be fabricated by calculating the effective medium parameters as discussed in the paper.

  12. Performance of TlCaBaCuO 30 GHz 64 element antenna array

    NASA Technical Reports Server (NTRS)

    Lewis, L. L.; Koepf, G.; Bhasin, K. B.; Richard, M. A.

    1993-01-01

    A 64-element, 30-GHz microstrip antenna array with corporate feed network was designed and built on a 0.254-mm (10-mil) thick lanthanum aluminate substrate. One antenna pattern was fabricated from gold film, and a second pattern used TlCaBaCuO high-temperature superconductor. Both antennas used gold ground planes deposited on the reverse side of the substrate. Gain and radiation patterns were measured for both antennas at room temperature and at cryogenic temperatures. Observations agree well with simple models for loss and microwave beam width, with a gain on boresight of 20.3 dB and beam width of 15 deg for the superconducting antenna. The antenna loss is only 1.9 dB.

  13. Antenna-coupled TES bolometers for the Keck array, Spider, and Polar-1

    NASA Astrophysics Data System (ADS)

    O'Brient, R.; Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Amiri, M.; Benton, S.; Bischoff, C.; Bock, J. J.; Bonetti, J. A.; Brevik, J. A.; Burger, B.; Davis, G.; Day, P.; Dowell, C. D.; Duband, L.; Filippini, J. P.; Fliescher, S.; Golwala, S. R.; Grayson, J.; Halpern, M.; Hasselfield, M.; Hilton, G.; Hristov, V. V.; Hui, H.; Irwin, K.; Kernasovskiy, S.; Kovac, J. M.; Kuo, C. L.; Leitch, E.; Lueker, M.; Megerian, K.; Moncelsi, L.; Netterfield, C. B.; Nguyen, H. T.; Ogburn, R. W.; Pryke, C. L.; Reintsema, C.; Ruhl, J. E.; Runyan, M. C.; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z.; Sudiwala, R.; Teply, G.; Tolan, J. E.; Turner, A. D.; Tucker, R. S.; Vieregg, A.; Wiebe, D. V.; Wilson, P.; Wong, C. L.; Wu, W. L. K.; Yoon, K. W.

    2012-09-01

    Between the BICEP2 and Keck Array experiments, we have deployed over 1500 dual polarized antenna coupled bolometers to map the Cosmic Microwave Background’s polarization. We have been able to rapidly deploy these detectors because they are completely planar with an integrated phased-array antenna. Through our experience in these experiments, we have learned of several challenges with this technology- specifically the beam synthesis in the antenna- and in this paper we report on how we have modified our designs to mitigate these challenges. In particular, we discus differential steering errors between the polarization pairs’ beam centroids due to microstrip cross talk and gradients of penetration depth in the niobium thin films of our millimeter wave circuits. We also discuss how we have suppressed side lobe response with a Gaussian taper of our antenna illumination pattern. These improvements will be used in Spider, Polar-1, and this season’s retrofit of Keck Array.

  14. Investigation of a wideband dual via fed circularly polarized patch antenna for applications in retrodirective arrays

    NASA Astrophysics Data System (ADS)

    Davidson, Kyle

    Retrodirective arrays are an ongoing topic of research, particularly for applications on air mobile platforms such as Unmanned Aerial Vehicles (UAV). To perform their task of establishing a broadband communications link in a dynamic environment requires electrically small, inexpensive, wideband antennas that are Circularly Polarized (CP). However most antennas that provide the bandwidth required with CP utilize non-standard components that cannot be manufactured in contemporary Computer Aided Manufacturing (CAM) facilities. This thesis explores ways to eliminate these non-standard components, principally air gaps and probes, and replace them with vias and multi-layer dielectrics. This investigation lead to the development of four configurations of a dual via fed circular patch antenna, with three different designs for the feed network: a two stage branch line coupler, a Wilkinson power divider with a 90 degree delay line, and a 90 degree hybrid. The experimental results included a version of this antenna operating at 3.0 GHz with a 33 % bandwidth across both the reflection coefficient and its axial ratio, comparing very well with simulations in Ansoft HFSS, and exceeding the performance of any published microstrip antenna that did not use non-standardard PCB components. This dual via fed design was then investigated in a 2 by 5 element linear array in order to develop an understanding of the coupling behaviour between elements. Keywords: microstrip antenna, mutual coupling, retrodirective arrays, circular polarization.

  15. Design of Compact Penta-Band and Hexa-Band Microstrip Antennas

    NASA Astrophysics Data System (ADS)

    Srivastava, Kunal; Kumar, Ashwani; Kanaujia, Binod K.

    2016-03-01

    This paper presents the design of two multi-band microstrip antennas. The antenna-1 gives Penta-Band and antenna-2 gives Hexa-band in the WLAN band. The frequency bands of the antenna-1 are Bluetooth 2.47 GHz (2.43 GHz-2.54 GHz), WiMax band 3.73 GHz (3.71 GHz-3.77 GHz), WLAN 5.1 GHz (4.99 GHz-5.13 GHz), upper WLAN 6.36 GHz (6.29 GHz-6.43 GHz), C band band 7.42 GHz (7.32 GHz-7.50 GHz) and the antenna-2 are WLAN band 2.6 GHz (2.56 GHz-2.63 GHz), 3.0 GHz (2.94 GHz-3.05 GHz), WiMax band 3.4 GHz (3.34 GHz-3.55 GHz), 4.85 GHz (4.81 GHz-4.92 GHz), WLAN 5.3 GHz (5.27 GHz-5.34 GHz) and upper WLAN 6.88 GHz. Both the antennas are fabricated and their measured results are presented to validate the simulated results. Proposed antennas have compact sizes and good radiation performances.

  16. Monolithic and integrated phased array antennas

    NASA Astrophysics Data System (ADS)

    Schaubert, Daniel H.; Pozar, David M.

    Some of the problems relevant to the design of monolithic and integrated arrays are examined. In particular, attention is given to electrical and mechanical design considerations, restrictions they impose on the choice of elements and architecture of integrated arrays, and elements that can alleviate one or more of these restrictions. Monolithic array designs are compared with some multiple-layer and two-sided designs using such criteria as scan range, bandwidth, substrate size and configuration, polarization, and feed line radiation. Broadside radiating elements, such as microstrip dipoles and patches, as well as end-fire radiating slots are considered.

  17. Adaptive antenna arrays for weak interfering signals

    NASA Technical Reports Server (NTRS)

    Gupta, I. J.

    1985-01-01

    The interference protection provided by adaptive antenna arrays to an Earth station or satellite receive antenna system is studied. The case where the interference is caused by the transmission from adjacent satellites or Earth stations whose signals inadverently enter the receiving system and interfere with the communication link is considered. Thus, the interfering signals are very weak. To increase the interference suppression, one can either decrease the thermal noise in the feedback loops or increase the gain of the auxiliary antennas in the interfering signal direction. Both methods are examined. It is shown that one may have to reduce the noise correlation to impractically low values and if directive auxiliary antennas are used, the auxiliary antenna size may have to be too large. One can, however, combine the two methods to achieve the specified interference suppression with reasonable requirements of noise decorrelation and auxiliary antenna size. Effects of the errors in the steering vector on the adaptive array performance are studied.

  18. Control of phased-array antennas

    NASA Astrophysics Data System (ADS)

    Samoilenko, V. I.; Shishov, Iu. A.

    Principles and algorithms for the control of phased arrays are described. Particular consideration is given to algorithms for the control of phase distribution, adaptive arrays, beam-steerable arrays, the design of phase shifters, the compensation of beam-pointing errors, and the calibration of high-gain antenna pointing.

  19. Ultrahigh frequency tunability of aperture-coupled microstrip antenna via electric-field tunable BST

    NASA Astrophysics Data System (ADS)

    Du, Hong-Lei; Xue, Qian; Gao, Xiao-Yang; Yao, Feng-Rui; Lu, Shi-Yang; Wang, Ye-Long; Liu, Chun-Heng; Zhang, Yong-Cheng; Lü, Yue-Guang; Li, Shan-Dong

    2015-12-01

    A composite ceramic with nominal composition of 45.0 wt%(Ba0.5Sr0.5)TiO3-55.0 wt%MgO (acronym is BST-MgO) is sintered for fabricating a frequency reconfigurable aperture-coupled microstrip antenna. The calcined BST-MgO composite ceramic exhibits good microwave dielectric properties at X-band with appropriate dielectric constant ɛr around 85, lower dielectric loss tan δ about 0.01, and higher permittivity tunability 14.8% at 8.33 kV/cm. An ultrahigh E-field tunability of working frequency up to 11.0% (i.e., from 9.1 GHz to 10.1 GHz with a large frequency shift of 1000 MHz) at a DC bias field from 0 to 8.33 kV/cm and a considerably large center gain over 7.5 dB are obtained in the designed frequency reconfigurable microstrip antenna. These results demonstrate that BST materials are promising for the frequency reconfigurable antenna. Project supported by the National Natural Science Foundation of China (Grant No. 11074040) and the Key Project of Shandong Provincial Department of Science and Technology, China (Grant No. ZR2012FZ006).

  20. Juno Microwave Radiometer Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, N.; Chen, J.; Focardi, P.; Hodges, R.; Hughes, R.; Jakoboski, J.; Venkatesan, J.; Zawadzki, M.

    2009-01-01

    Juno is a mission in the NASA New Frontiers Program with the goal of significantly improving our understanding of the formation and structure of Jupiter. This paper discusses the modeling and measurement of the two patch array antennas. An overview of the antenna architecture, design and development at JPL is provided, along with estimates of performance and the results of measurements.

  1. Antenna-array, phase quadrature tracking system

    NASA Technical Reports Server (NTRS)

    Cubley, H. D.

    1970-01-01

    Phase relationship between input signals appearing on widely-spaced parallel connected antenna elements in array is automatically adjusted in phase quadrature tracking system. Compact and lightweight design permit use in wide variety of airborne communications networks.

  2. Effective Permeability and Miniaturization Estimation of Ferrite-loaded Microstrip Patch Antenna

    NASA Astrophysics Data System (ADS)

    Saini, Ashish; Thakur, Atul; Thakur, Preeti

    2016-08-01

    Miniaturization of a microstrip patch antenna using composite nanosized ferrite material is proposed in this paper. Detailed simulations were performed to analyze the effect of increase in relative permeability of substrate material on physical size and efficiency of a microstrip antenna. An analytical expression for estimation of the effective relative permeability is established here on the basis of the detailed simulation. Composite nano ferrite (Mn0.5Zn0.35Co0.15Fe2O4 + SrFe12O19) with an average crystallite size of 72 nm was synthesized and characterized for electromagnetic properties. The substrate material was prepared by the co-precipitation method. Matching values of complex permittivity ( ɛ* = 4.1-0.1j) and complex permeability ( μ* = 3.72-0.28j) up to 1 GHz were obtained from the electromagnetic characterization. Measurement of the resonant frequency of the fabricated antenna validates the derived expression of effective relative permeability. It reduces the error in calculation of resonant frequency from 10% to 1%. Simulation and measurement results also confirm that an antenna fabricated with the above parameters can reduce the patch size by almost 44% and increases -10 dB reflection loss bandwidth over a pure dielectric FR4 substrate. Therefore, we propose here an analytical expression for estimation of effective relative permeability and Mn0.5Zn0.35Co0.15Fe2O4 + SrFe12O19 composite nano ferrites as suitable candidate for a high-bandwidth miniaturized antenna in the microwave frequency range.

  3. Effective Permeability and Miniaturization Estimation of Ferrite-loaded Microstrip Patch Antenna

    NASA Astrophysics Data System (ADS)

    Saini, Ashish; Thakur, Atul; Thakur, Preeti

    2016-05-01

    Miniaturization of a microstrip patch antenna using composite nanosized ferrite material is proposed in this paper. Detailed simulations were performed to analyze the effect of increase in relative permeability of substrate material on physical size and efficiency of a microstrip antenna. An analytical expression for estimation of the effective relative permeability is established here on the basis of the detailed simulation. Composite nano ferrite (Mn0.5Zn0.35Co0.15Fe2O4 + SrFe12O19) with an average crystallite size of 72 nm was synthesized and characterized for electromagnetic properties. The substrate material was prepared by the co-precipitation method. Matching values of complex permittivity (ɛ* = 4.1-0.1j) and complex permeability (μ* = 3.72-0.28j) up to 1 GHz were obtained from the electromagnetic characterization. Measurement of the resonant frequency of the fabricated antenna validates the derived expression of effective relative permeability. It reduces the error in calculation of resonant frequency from 10% to 1%. Simulation and measurement results also confirm that an antenna fabricated with the above parameters can reduce the patch size by almost 44% and increases -10 dB reflection loss bandwidth over a pure dielectric FR4 substrate. Therefore, we propose here an analytical expression for estimation of effective relative permeability and Mn0.5Zn0.35Co0.15Fe2O4 + SrFe12O19 composite nano ferrites as suitable candidate for a high-bandwidth miniaturized antenna in the microwave frequency range.

  4. Low-Cost Dielectric Substrate for Designing Low Profile Multiband Monopole Microstrip Antenna

    PubMed Central

    Ahsan, M. R.; Islam, M. T.; Habib Ullah, M.; Arshad, H.; Mansor, M. F.

    2014-01-01

    This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm2 radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53–2.89 GHz) and 440 MHz (3.47–3.91 GHz) for WiMAX and 1550 MHz (6.28–7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively. PMID:25136648

  5. Low-cost dielectric substrate for designing low profile multiband monopole microstrip antenna.

    PubMed

    Ahsan, M R; Islam, M T; Habib Ullah, M; Arshad, H; Mansor, M F

    2014-01-01

    This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm(2) radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53-2.89 GHz) and 440 MHz (3.47-3.91 GHz) for WiMAX and 1550 MHz (6.28-7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively. PMID:25136648

  6. Compact Double-P Slotted Inset-Fed Microstrip Patch Antenna on High Dielectric Substrate

    PubMed Central

    Ahsan, M. R.; Islam, M. T.; Habib Ullah, M.; Mahadi, W. N. L.; Latef, T. A.

    2014-01-01

    This paper presents a compact sized inset-fed rectangular microstrip patch antenna embedded with double-P slots. The proposed antenna has been designed and fabricated on ceramic-PTFE composite material substrate of high dielectric constant value. The measurement results from the fabricated prototype of the antenna show −10 dB reflection coefficient bandwidths of 200 MHz and 300 MHz with center resonant frequency of 1.5 GHz and 4 GHz, respectively. The fabricated antenna has attained gains of 3.52 dBi with 81% radiation efficiency and 5.72 dBi with 87% radiation efficiency for lower band and upper band, respectively. The measured E- and H-plane radiation patterns are also presented for better understanding. Good agreement between the simulation and measurement results and consistent radiation patterns make the proposed antenna suitable for GPS and C-band applications. PMID:25165750

  7. Full wave analysis and miniaturization of microstrip antenna on ferrimagnetics substrates

    NASA Astrophysics Data System (ADS)

    Lavor, Otávio Paulino; Fernandes, Humberto Cesar Chaves

    2016-02-01

    This paper presents the miniaturization of the microstrip antenna on ferrimagnetic substrate for operate at a frequency of 2.5 GHz, where the full wave method Transverse Transmission Line-TTL is used it for obtain resonance frequency. For validate this method in these substrates, the results as function of DC magnetic field are shown. When the field is 132.6 AT/m, the value of reference is 151.7 MHz and the value of TTL is 151.3 MHz. The dimensions are obtained for the frequency of 2.5 GHz and a comparison is done with ferrites and conventional substrate, showing a reduction in volume of the antenna of 2808.96 mm3 for 0.39 mm3 when the ferrites are used.

  8. Design of transversely fed EMC microstrip dipole arrays including mutual coupling

    NASA Astrophysics Data System (ADS)

    Yang, Hung-Yu; Alexopoulos, Nicolaos G.; Lepeltier, Philippe M.; Stern, George J.

    1990-02-01

    Design techniques and procedures for microstrip dipole arrays transversely fed by proximity coupled microstrip lines are presented. Two design equations which include the effects of mutual coupling are developed, and the corresponding design curves are obtained by a rigorous integral equation solution. A seven-element standing wave linear array is designed to illustrate the developed design procedures. The design data are checked by a complete integral equation solution of the array, with good agreement. The measurements of radiation pattern and input impedance are found to be in good agreement with the design goal.

  9. General view looking northnorthwest at antenna array. Troposhperic scatter communications ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view looking north-northwest at antenna array. Troposhperic scatter communications antennas are seen at far left, transmitter building is in center, antenna array at right - Over-the-Horizon Backscatter Radar Network, Moscow Radar Site Transmit Sector One Antenna Array, At the end of Steam Road, Moscow, Somerset County, ME

  10. Antenna arraying performance for deep space telecommunications systems

    NASA Technical Reports Server (NTRS)

    Stelzried, C. T.; Berman, A. L.; Noreen, G. K.

    1983-01-01

    Antenna arraying is a crucial Deep Space Network technique in maximizing the science return of planetary and comet encounters. The equations which describe the total figure of merit for a multiple system of arrayed antennas are developed. An example is given for three Canberra DSN antennas and the Parkes 64-m antenna to be arrayed for the Voyager 2 Uranus flyby.

  11. Antenna arraying performance for deep space telecommunications systems

    NASA Astrophysics Data System (ADS)

    Stelzried, C. T.; Berman, A. L.; Noreen, G. K.

    1983-02-01

    Antenna arraying is a crucial Deep Space Network technique in maximizing the science return of planetary and comet encounters. The equations which describe the total figure of merit for a multiple system of arrayed antennas are developed. An example is given for three Canberra DSN antennas and the Parkes 64-m antenna to be arrayed for the Voyager 2 Uranus flyby.

  12. A wide-band dual-polarized VHF microstrip antenna for global sensing of sea ice thickness

    NASA Technical Reports Server (NTRS)

    Huang, John; Hussein, Ziad; Petros, Argy

    2005-01-01

    A VHF microstrip patch antenna was developed to achieve a bandwidth of 45 MHz (30%) from 127 MHz to 172 MHz with dual-linear-polarization capability. This microstrip antenna used foam substrates and dual stacked patches with capacitive probe feeds to achieve wide bandwidth. Four such capacitive feeds were used to achieve dual polarizations with less than -20 dB of cross-polarization level. Twenty-four shorting pins were used on the lower patch to achieve acceptable isolation between the four feed probes. This antenna has a measured gain of 8.5 dB at 137 MHz and 10 dB at 162 MHz. By using the Method of Moments technique, multipath scattering patterns were calculated when the antenna is mounted on the outside of a Twin Otter aircraft.

  13. Far-infrared imaging antenna arrays

    NASA Technical Reports Server (NTRS)

    Neikirk, D. P.; Rutledge, D. B.; Muha, M. S.; Park, H.; Yu, C.-X.

    1982-01-01

    A far-infrared monolithic imaging antenna array with diffraction-limited resolution has been demonstrated. The optical system is similar to an oil-immersion microscope, except that the position of the object and the image are interchanged. The array is a series of evaporated silver bow-tie antennas of 75 nm thick, spaced at 310 microns, on a fused-quartz substrate; the bow angle of 60 deg gives an impedance of 150 ohm to match to bismuth microbolometers. The measured responsivity of the array elements is 1-2 V/W at the relatively low bias of 1 mA. Previous measurements have shown that the bolometers are 1/f noise limited up to 100 kHz and that they have a frequency response of 5 MHz. The antenna array should be adequate for far-infrared plasma interferometer measurements.

  14. A generalized method for the evaluation of mutual coupling in microstrip arrays

    NASA Astrophysics Data System (ADS)

    Katehi, Pisti B.

    1987-02-01

    An analytical method for the evaluation of mutual coupling in microstrip arrays is discussed. The elements of the array are excited by microstriplines printed on or embedded in the substrate. As an example, the mutual coupling between microstrip dipoles electromagnetically coupled to embedded strip transmission lines is evaluated accurately. The present method is valid in the millimeter range as well as at microwave frequencies and does not have any substrate limitations. Also, it accounts for conductor thickness and surface wave excitation. Comparison with experimental results show excellent agreement.

  15. Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design.

    PubMed

    Ahsan, Md Rezwanul; Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Ali, Mohd Tarmizi

    2015-01-01

    A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB) and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz) RFID, WiMAX (3.5/5.5 GHz) and WLAN (5.2/5.8 GHz) applications. PMID:26018795

  16. Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design

    PubMed Central

    Ahsan, Md Rezwanul; Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Ali, Mohd Tarmizi

    2015-01-01

    A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB) and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz) RFID, WiMAX (3.5/5.5 GHz) and WLAN (5.2/5.8 GHz) applications. PMID:26018795

  17. Magnetic antenna excitation of whistler modes. II. Antenna arrays

    SciTech Connect

    Stenzel, R. L.; Urrutia, J. M.

    2014-12-15

    The excitation of whistler modes from magnetic loop antennas has been investigated experimentally. The field topology of the excited wave driven by a single loop antenna has been measured for different loop orientations with respect to the uniform background field. The fields from two or more antennas at different locations are then created by superposition of the single-loop data. It is shown that an antenna array can produce nearly plane waves which cannot be achieved with single antennas. By applying a phase shift along the array, oblique wave propagation is obtained. This allows a meaningful comparison with plane wave theory. The Gendrin mode and oblique cyclotron resonance are demonstrated. Wave helicity and polarization in space and time are demonstrated and distinguished from the magnetic helicity of the wave field. The superposition of two oblique plane whistler modes produces in a “whistler waveguide” mode whose polarization and helicity properties are explained. The results show that single point measurements cannot properly establish the wave character of wave packets. The laboratory observations are relevant for excitation and detection of whistler modes in space plasmas.

  18. Tilted Microstrip Phased Arrays With Improved Electromagnetic Decoupling for Ultrahigh-Field Magnetic Resonance Imaging

    PubMed Central

    Pang, Yong; Wu, Bing; Jiang, Xiaohua; Vigneron, Daniel B.; Zhang, Xiaoliang

    2014-01-01

    Abstract One of the technical challenges in designing a dedicated transceiver radio frequency (RF) array for MR imaging in humans at ultrahigh magnetic fields is how to effectively decouple the resonant elements of the array. In this work, we propose a new approach using tilted microstrip array elements for improving the decoupling performance and potentially parallel imaging capability. To investigate and validate the proposed design technique, an 8-channel volume array with tilted straight-type microstrip elements was designed, capable for human imaging at the ultrahigh field of 7 Tesla. In this volume transceiver array, its electromagnetic decoupling behavior among resonant elements, RF field penetration to biological samples, and parallel imaging performance were studied through bench tests and in vivo MR imaging experiments. In this specific tilted element array design, decoupling among array elements changes with the tilted angle of the elements and the best decoupling can be achieved at certain tilted angle. In vivo human knee MR images were acquired using the tilted volume array at 7 Tesla for method validation. Results of this study demonstrated that the electromagnetic decoupling between array elements and the B1 field strength can be improved by using the tilted element method in microstrip RF coil array designs at the ultrahigh field of 7T. PMID:25526481

  19. Breadboard Signal Processor for Arraying DSN Antennas

    NASA Technical Reports Server (NTRS)

    Jongeling, Andre; Sigman, Elliott; Chandra, Kumar; Trinh, Joseph; Soriano, Melissa; Navarro, Robert; Rogstad, Stephen; Goodhart, Charles; Proctor, Robert; Jourdan, Michael; Rayhrer, Benno

    2008-01-01

    A recently developed breadboard version of an advanced signal processor for arraying many antennas in NASA s Deep Space Network (DSN) can accept inputs in a 500-MHz-wide frequency band from six antennas. The next breadboard version is expected to accept inputs from 16 antennas, and a following developed version is expected to be designed according to an architecture that will be scalable to accept inputs from as many as 400 antennas. These and similar signal processors could also be used for combining multiple wide-band signals in non-DSN applications, including very-long-baseline interferometry and telecommunications. This signal processor performs functions of a wide-band FX correlator and a beam-forming signal combiner. [The term "FX" signifies that the digital samples of two given signals are fast Fourier transformed (F), then the fast Fourier transforms of the two signals are multiplied (X) prior to accumulation.] In this processor, the signals from the various antennas are broken up into channels in the frequency domain (see figure). In each frequency channel, the data from each antenna are correlated against the data from each other antenna; this is done for all antenna baselines (that is, for all antenna pairs). The results of the correlations are used to obtain calibration data to align the antenna signals in both phase and delay. Data from the various antenna frequency channels are also combined and calibration corrections are applied. The frequency-domain data thus combined are then synthesized back to the time domain for passing on to a telemetry receiver

  20. Optically controlled phased-array antenna technology for space communication systems

    NASA Technical Reports Server (NTRS)

    Kunath, Richard R.; Bhasin, Kul B.

    1988-01-01

    Using MMICs in phased-array applications above 20 GHz requires complex RF and control signal distribution systems. Conventional waveguide, coaxial cable, and microstrip methods are undesirable due to their high weight, high loss, limited mechanical flexibility and large volume. An attractive alternative to these transmission media, for RF and control signal distribution in MMIC phased-array antennas, is optical fiber. Presented are potential system architectures and their associated characteristics. The status of high frequency opto-electronic components needed to realize the potential system architectures is also discussed. It is concluded that an optical fiber network will reduce weight and complexity, and increase reliability and performance, but may require higher power.

  1. An LTCC 94 GHz Antenna Array

    SciTech Connect

    Aguirre, J; Pao, H; Lin, H; Garland, P; O'Neill, D; Horton, K

    2007-12-21

    An antenna array is designed in low-temperature cofired ceramic (LTCC) Ferro A6M{trademark} for a mm-wave application. The antenna is designed to operate at 94 GHz with a few percent bandwidth. A key manufacturing technology is the use of 3 mil diameter vias on a 6 mil pitch to construct the laminated waveguides that form the beamforming network and radiating elements. Measurements for loss in the laminated waveguide are presented. The slot-fed cavity-radiating element is designed to account for extremely tight mutual coupling between elements. The array incorporates a slot-fed multi-layer beamforming network.

  2. Deployable Wide-Aperture Array Antennas

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W.; Dobbins, Justin A.; Lin, Greg Y.; Chu, Andrew; Scully, Robert C.

    2005-01-01

    Inexpensive, lightweight array antennas on flexible substrates are under development to satisfy a need for large-aperture antennas that can be stored compactly during transport and deployed to full size in the field. Conceived for use aboard spacecraft, antennas of this type also have potential terrestrial uses . most likely, as means to extend the ranges of cellular telephones in rural settings. Several simple deployment mechanisms are envisioned. One example is shown in the figure, where the deployment mechanism, a springlike material contained in a sleeve around the perimeter of a flexible membrane, is based on a common automobile window shade. The array can be formed of antenna elements that are printed on small sections of semi-flexible laminates, or preferably, elements that are constructed of conducting fabric. Likewise, a distribution network connecting the elements can be created from conventional technologies such as lightweight, flexible coaxial cable and a surface mount power divider, or preferably, from elements formed from conductive fabrics. Conventional technologies may be stitched onto a supporting flexible membrane or contained within pockets that are stitched onto a flexible membrane. Components created from conductive fabrics may be attached by stitching conductive strips to a nonconductive membrane, embroidering conductive threads into a nonconductive membrane, or weaving predetermined patterns directly into the membrane. The deployable antenna may comprise multiple types of antenna elements. For example, thin profile antenna elements above a ground plane, both attached to the supporting flexible membrane, can be used to create a unidirectional boresight radiation pattern. Or, antenna elements without a ground plane, such as bow-tie dipoles, can be attached to the membrane to create a bidirectional array such as that shown in the figure. For either type of antenna element, the dual configuration, i.e., elements formed of slots in a conductive

  3. A 10 GHz Y-Ba-Cu-O/GaAs hybrid oscillator proximity coupled to a circular microstrip patch antenna

    NASA Technical Reports Server (NTRS)

    Rohrer, Norman J.; Richard, M. A.; Valco, George J.; Bhasin, Kul B.

    1993-01-01

    A 10 GHz hybrid Y-Ba-Cu-O / GaAs microwave oscillator proximity coupled to a circular microstrip antenna was designed, fabricated and characterized. The oscillator was a reflection mode type using a GaAs MESFET as the active element. The feedline, transmission lines, RF chokes, and bias lines were all fabricated from YBa2Cu3O(7-x) superconducting thin films on a 1 cm x 1 cm lanthanum aluminate substrate. The output feedline of the oscillator was wire bonded to a superconducting feedline on a second 1 cm x 1 cm lanthanum aluminate substrate, which was in turn proximity coupled to a circular microstrip patch antenna. Antenna patterns from this active patch antenna and the performance of the oscillator measured at 77 K are reported. The oscillator had a maximum output power of 11.5 dBm at 77 K, which corresponded to an efficiency of 10 percent. In addition, the efficiency of the microstrip patch antenna together with its high temperature superconducting feedline was measured from 85 K to 30 K and was found to be 71 percent at 77 4 increasing to a maximum of 87.4 percent at 30 K.

  4. A 10 GHz Y-Ba-Cu-O/GaAs hybrid oscillator proximity coupled to a circular microstrip patch antenna

    NASA Technical Reports Server (NTRS)

    Rohrer, Norman J.; Richard, M. A.; Valco, George J.; Bhasin, Kul B.

    1993-01-01

    A 10 GHz hybrid YBCO/GaAs microwave oscillator proximity coupled to a circular microstrip antenna has been designed, fabricated, and characterized. The oscillator was a reflection mode type using a GaAs MESFET as the active element. The feedline, transmission lines, RF chokes, and bias lines were all fabricated from YBCO superconducting thin films on a 1 cm x 1 cm lanthanum aluminate substrate. The output feedline of the oscillator was wire bonded to a superconducting feedline on a second 1 cm x 1 cm lanthanum aluminate substrate, which was in turn proximity coupled to a circular microstrip patch antenna. Antenna patterns from this active patch antenna and the performance of the oscillator measured at 77 K are reported. The oscillator had a maximum output power of 11.5 dBm at 77 K, which corresponded to an efficiency of 10 percent. In addition, the efficiency of the microstrip patch antenna together with its high temperature superconducting feedline was measured from 85 K to 30 K and was found to be 71 percent at 77 K, increasing to a maximum of 87.4 percent at 30 K.

  5. Enhanced bandwidth of a microstrip antenna using a parasitic mushroom-like metamaterial structure for multi-robot cooperative navigation

    NASA Astrophysics Data System (ADS)

    Lee, Cherl-Hee; Lee, Jonghun; Kim, Yoon-Gu; An, Jinung

    2015-01-01

    The broadband design of a microstrip patch antenna is presented and experimentally studied for multi-robot cooperation. A parasitic mushroom-like metamaterial (MTM) patch close to a microstrip top patch is excited through gap-coupling, thereby producing a resonance frequency. Because of the design, the resonance frequency of the parasitic MTM patch is adjacent to that of the main patch, and the presented antenna can achieve an enhanced bandwidth of 450 MHz, which is about two times the bandwidth of a conventional patch antenna without the MTM parasitic patch. The error rate of packet transmissions for measuring the distance between a leader robot and a follower robot was also improved by almost two-fold.

  6. Dual-band operation of a microstrip patch antenna on a Duroid 5870 substrate for Ku- and K-bands.

    PubMed

    Islam, M M; Islam, M T; Faruque, M R I

    2013-01-01

    The dual-band operation of a microstrip patch antenna on a Duroid 5870 substrate for Ku- and K-bands is presented. The fabrication of the proposed antenna is performed with slots and a Duroid 5870 dielectric substrate and is excited by a 50 Ω microstrip transmission line. A high-frequency structural simulator (HFSS) is used which is based on the finite element method (FEM) in this research. The measured impedance bandwidth (2 : 1 VSWR) achieved is 1.07 GHz (15.93 GHz-14.86 GHz) on the lower band and 0.94 GHz (20.67-19.73 GHz) on the upper band. A stable omnidirectional radiation pattern is observed in the operating frequency band. The proposed prototype antenna behavior is discussed in terms of the comparisons of the measured and simulated results. PMID:24385878

  7. Dual-Band Operation of a Microstrip Patch Antenna on a Duroid 5870 Substrate for Ku- and K-Bands

    PubMed Central

    Islam, M. M.; Islam, M. T.; Faruque, M. R. I.

    2013-01-01

    The dual-band operation of a microstrip patch antenna on a Duroid 5870 substrate for Ku- and K-bands is presented. The fabrication of the proposed antenna is performed with slots and a Duroid 5870 dielectric substrate and is excited by a 50 Ω microstrip transmission line. A high-frequency structural simulator (HFSS) is used which is based on the finite element method (FEM) in this research. The measured impedance bandwidth (2 : 1 VSWR) achieved is 1.07 GHz (15.93 GHz–14.86 GHz) on the lower band and 0.94 GHz (20.67–19.73 GHz) on the upper band. A stable omnidirectional radiation pattern is observed in the operating frequency band. The proposed prototype antenna behavior is discussed in terms of the comparisons of the measured and simulated results. PMID:24385878

  8. A Dual-polarized Microstrip Subarray Antenna for an Inflatable L-band Synthetic Aperture Radar

    NASA Technical Reports Server (NTRS)

    Zawadzki, Mark; Huang, John

    1999-01-01

    Inflatable technology has been identified as a potential solution to the problem of achieving small mass, high packaging efficiency, and reliable deployment for future NASA spaceborne synthetic aperture radar (SAR) antennas. Presently, there exists a requirement for a dual-polarized L-band SAR antenna with an aperture size of 10m x 3m, a center frequency of 1.25GHz, a bandwidth of 80MHz, electronic beam scanning, and a mass of less than 100kg. The work presented below is part of the ongoing effort to develop such an inflatable antenna array.

  9. Computing resonant frequency of C-shaped compact microstrip antennas by using ANFIS

    NASA Astrophysics Data System (ADS)

    Akdagli, Ali; Kayabasi, Ahmet; Develi, Ibrahim

    2015-03-01

    In this work, the resonant frequency of C-shaped compact microstrip antennas (CCMAs) operating at UHF band is computed by using the adaptive neuro-fuzzy inference system (ANFIS). For this purpose, 144 CCMAs with various relative dielectric constants and different physical dimensions were simulated by the XFDTD software package based on the finite-difference time domain (FDTD) method. One hundred and twenty-nine CCMAs were employed for training, while the remaining 15 CCMAs were used for testing of the ANFIS model. Average percentage error (APE) values were obtained as 0.8413% and 1.259% for training and testing, respectively. In order to demonstrate its validity and accuracy, the proposed ANFIS model was also tested over the simulation data given in the literature, and APE was obtained as 0.916%. These results show that ANFIS can be successfully used to compute the resonant frequency of CCMAs.

  10. Clutter sensitivity test under controlled field conditions Resonant Microstrip Patch Antenna (RMPA) sensor technology

    SciTech Connect

    1996-06-27

    Theoretical research, controlled laboratory tests, and these field test results show that nonmetallic (and metallic) shallowly buried objects can be detected and imaged with the Resonant Microstrip Patch Antenna (RMPA) sensor. The sensor can be modeled as a high Q cavity which capitalizes on its resonant condition sensitivity to scattered waves from buried objects. When the RMPA sensor is swept over a shallowly buried object, the RMPA fed-point impedance (resistance), measured with a Maxwell bridge, changes by tens of percent. The significant change in unprocessed impedance data can be presented in two-dimensional and three-dimensional graphical displays over the survey area. This forms silhouette images of the objects without the application of computationally intensive data processing algorithms. Because RMPA employed electromagnetic waves to illuminate the shallowly buried object, a number of questions and issues arise in the decision to fund or deny funding of the reconfiguration of the RMPA technology into a nonmetallic (metallic) land mine detector.

  11. Oblique view to the northwest of the Antenna Array ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique view to the northwest of the Antenna Array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Six Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  12. General view of Antenna Array and building complex, looking southwest ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of Antenna Array and building complex, looking southwest - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Six Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

  13. Detail view to the east of the Antenna Array ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view to the east of the Antenna Array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Six Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  14. General view to the south of the antenna array ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view to the south of the antenna array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Five Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  15. General view to the northwest of the antenna array ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view to the northwest of the antenna array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Five Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  16. General view of Antenna Array and building complex, looking northeast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of Antenna Array and building complex, looking northeast - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Six Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

  17. Detail view looking eastnortheast at elements of antenna array ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view looking east-northeast at elements of antenna array - Over-the-Horizon Backscatter Radar Network, Moscow Radar Site Transmit Sector One Antenna Array, At the end of Steam Road, Moscow, Somerset County, ME

  18. Multiband Photonic Phased-Array Antenna

    NASA Technical Reports Server (NTRS)

    Tang, Suning

    2015-01-01

    A multiband phased-array antenna (PAA) can reduce the number of antennas on shipboard platforms while offering significantly improved performance. Crystal Research, Inc., has developed a multiband photonic antenna that is based on a high-speed, optical, true-time-delay beamformer. It is capable of simultaneously steering multiple independent radio frequency (RF) beams in less than 1,000 nanoseconds. This high steering speed is 3 orders of magnitude faster than any existing optical beamformer. Unlike other approaches, this technology uses a single controlling device per operation band, eliminating the need for massive optical switches, laser diodes, and fiber Bragg gratings. More importantly, only one beamformer is needed for all antenna elements.

  19. Biologically-inspired, electrically small antenna arrays

    NASA Astrophysics Data System (ADS)

    Masoumi, Amir Reza

    First, the motivation behind adding a passive external coupling network after antenna arrays is discussed, the concept of biomimetic antenna arrays (BMAAs) introduced and some of the previous work done in this area have been reviewed. Next, a BMAA which achieves an angular resolution of roughly 15 times its regular counterpart is introduced and fully characterized. The introduced BMAA employs transformers which considerably degrade its performance, namely its output power. To cicumvent this shortcoming a new architecture of a BMAA that does not employ transformers and therefore yields a higher output power for the same angular resolution has been subsequently presented. Moreover, a detailed noise analysis of this BMAA is carried out and the output noise of the new architecture is compared with the output noise of the original design. The modified twoelement BMAA architecture is then extended to multiple elements. A novel nonlinear optimization process is introduced that maximizes the total power captured by the BMAA for a given angular resolution and the concept illustrated for a three-element antenna array. Next an optimum two-element BMAA which achieves the maximum possible angular resolution while obtaining the same output power level of a regular antenna array with the same elements and spacing is introduced. A novel two-element superdirective array based on this optimum BMAA has been also discussed. The passive BMAAs discussed in this thesis have a relatively narrow bandwidth. To extend the bandwidth of BMAAs, non- Foster networks have been employed in their external coupling networks and it has been demonstrated that they can increase their bandwidth by a factor of roughly 33. Finally, the BMAA concept has been extended to nano-antenna arrays and a concept for designing sub-wavelength angle-sensing detectors at optical wavelengths has been introduced.

  20. Phased Antenna Array for Global Navigation Satellite System Signals

    NASA Technical Reports Server (NTRS)

    Turbiner, Dmitry (Inventor)

    2015-01-01

    Systems and methods for phased array antennas are described. Supports for phased array antennas can be constructed by 3D printing. The array elements and combiner network can be constructed by conducting wire. Different parameters of the antenna, like the gain and directivity, can be controlled by selection of the appropriate design, and by electrical steering. Phased array antennas may be used for radio occultation measurements.

  1. Terahertz Array Receivers with Integrated Antennas

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam; Llombart, Nuria; Lee, Choonsup; Jung, Cecile; Lin, Robert; Cooper, Ken B.; Reck, Theodore; Siles, Jose; Schlecht, Erich; Peralta, Alessandro; Thomas, Bertrand; Mehdi, Imran

    2011-01-01

    Highly sensitive terahertz heterodyne receivers have been mostly single-pixel. However, now there is a real need of multi-pixel array receivers at these frequencies driven by the science and instrument requirements. In this paper we explore various receiver font-end and antenna architectures for use in multi-pixel integrated arrays at terahertz frequencies. Development of wafer-level integrated terahertz receiver front-end by using advanced semiconductor fabrication technologies has progressed very well over the past few years. Novel stacking of micro-machined silicon wafers which allows for the 3-dimensional integration of various terahertz receiver components in extremely small packages has made it possible to design multi-pixel heterodyne arrays. One of the critical technologies to achieve fully integrated system is the antenna arrays compatible with the receiver array architecture. In this paper we explore different receiver and antenna architectures for multi-pixel heterodyne and direct detector arrays for various applications such as multi-pixel high resolution spectrometer and imaging radar at terahertz frequencies.

  2. Coplanar waveguide fed phased array antenna

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Ponchak, George E.; Lee, R. Q.; Fernandez, N. S.

    1990-01-01

    A K-band four element linear phased array was designed and tested. Coplanar waveguide (CPW) is used for the microwave distribution system. A CPW to twin strip transition is used to interface with the printed dipole antennas. MMIC phased shifters are used for phase control.

  3. Interleaved arrays antenna technology development

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Phase one and two of a program to further develop and investigate advanced graphite epoxy waveguides, radiators, and components with application to space antennas are discussed. The objective of the two phases were to demonstrate mechanical integrity of a small panel of radiators and parts procured under a previous contract and to develop alternate designs and applications of the technology. Most of the emphasis was on the assembly and test of a 5 x 5 element module. This effort was supported by evaluation of adhesives and waveguide joint configurations. The evaluation and final assembly considered not only mechanical performance but also producibility in large scale.

  4. Phased array-fed antenna configuration study

    NASA Technical Reports Server (NTRS)

    Crosswell, W. F.; Ball, D. E.; Taylor, R. C.

    1983-01-01

    The scope of this contract entails a configuration study for a phased array fed transmit antenna operating in the frequency band of 17.7 to 20.2 GHz. This initial contract provides a basis for understanding the design limitations and advantages of advanced phased array and cluster feeds (both utilizing intergral MMIC modules) illuminating folded reflector optics (both near field and focused types). Design parametric analyses are performed utilizing as constraints the objective secondary performance requirements of the Advanced Communications Technology Satellite (Table 1.0). The output of the study provides design information which serves as a data base for future active phased array fed antenna studies such as detailed designs required to support the development of a ground tested breadboard. In general, this study is significant because it provides the antenna community with an understanding of the basic principles which govern near field phased scanned feed effects on secondary reflector system performance. Although several articles have been written on analysis procedures and results for these systems, the authors of this report have observed phenomenon of near field antenna systems not previously documented. Because the physical justification for the exhibited performance is provided herein, the findings of this study add a new dimension to the available knowledge of the subject matter.

  5. Simulation-based analysis of performance parameters of microstrip antennas with criss-cross metamaterial-based artificial substrate

    NASA Astrophysics Data System (ADS)

    Inamdar, Kirti; Kosta, Y. P.; Patnaik, S.

    2014-10-01

    In this paper, we present the design of a metamaterial-based microstrip patch antenna, optimized for bandwidth and multiple frequency operations. A criss-cross structure has been proposed, this shape has been inspired from the famous Jerusalem cross. The theory and design formulas to calculate various parameters of the proposed antenna have been presented. Design starts with the analysis of the proposed unit cell structure, and validating the response using software- HFSS Version 13, to obtain negative response of ε and μ- metamaterial. Following this, a metamaterial-based-microstrip-patch-antenna is designed. A detailed comparative study is conducted exploring the response of the designed patch made of metamaterial and that of the conventional patch. Finally, antenna parameters such as gain, bandwidth, radiation pattern, and multiple frequency responses are investigated and optimised for the same and present in table and response graphs. It is also observed that the physical dimension of the metamaterial-based patch antenna is smaller compared to its conventional counterpart operating at the same fundamental frequency. The challenging part was to develop metamaterial based on some signature structures and techniques that would offer advantage in terms of BW and multiple frequency operation, which is demonstrated in this paper. The unique shape proposed in this paper gives improvement in bandwidth without reducing the gain of the antenna.

  6. A Compact and Broadband Differential Microstrip Line to Rectangular Waveguide Transition Using Dipole Antenna

    NASA Astrophysics Data System (ADS)

    Yang, Ziqiang; Yang, Tao; Liu, Yu; Peng, Hao

    2016-02-01

    In this paper, a compact full Ka-band differential microstrip line (DML) to rectangular waveguide transition is proposed. The dipole antenna with semi-elliptic arms is introduced to transform the differential mode of DML to the TE10 mode of the rectangular waveguide directly. The two arms of the dipole antenna are connected together by a shorting strip to reduce the size of the dipole. Compared with the DML-to-waveguide transition using the fin-line topology, the size of the proposed transition has been reduced by 86 %. To verify this transition, a back-to-back structure is fabricated and tested. It provides a return loss of better than 15.2 dB and an insertion loss of 0.73 to 1.07 dB within a wide frequency range from 26.5 to 40 GHz. The measurement results show good agreement with the simulation results. Furthermore, a tolerance analysis is also performed via the simulation to prove that this transition is robust in the fabrication and mechanical assembly.

  7. A Compact and Broadband Differential Microstrip Line to Rectangular Waveguide Transition Using Dipole Antenna

    NASA Astrophysics Data System (ADS)

    Yang, Ziqiang; Yang, Tao; Liu, Yu; Peng, Hao

    2016-06-01

    In this paper, a compact full Ka-band differential microstrip line (DML) to rectangular waveguide transition is proposed. The dipole antenna with semi-elliptic arms is introduced to transform the differential mode of DML to the TE10 mode of the rectangular waveguide directly. The two arms of the dipole antenna are connected together by a shorting strip to reduce the size of the dipole. Compared with the DML-to-waveguide transition using the fin-line topology, the size of the proposed transition has been reduced by 86 %. To verify this transition, a back-to-back structure is fabricated and tested. It provides a return loss of better than 15.2 dB and an insertion loss of 0.73 to 1.07 dB within a wide frequency range from 26.5 to 40 GHz. The measurement results show good agreement with the simulation results. Furthermore, a tolerance analysis is also performed via the simulation to prove that this transition is robust in the fabrication and mechanical assembly.

  8. Spiral slotted phased antenna array

    NASA Technical Reports Server (NTRS)

    Ellis, H., Jr. (Inventor)

    1982-01-01

    A flush mounting, cavity-backed, dual orthogonal slot antenna for aircraft and space vehicles is described. Improved radiation pattern characteristics are obtained by making the spiral slot pattern elliptical in the aperture plane. A cavity and a flanged aperture plate are configured such that one slot pair is orthogonal with respect to another slot pair within the aperture plate. Coaxial split-tube baluns are used to drive the junctions between corresponding slot pairs. An optional cavity dielectric is provided and a drive coupling arrangement includes a four port comparator hybrid having sum and difference ports respectively, for alternate excitation to produce a single lobe or a double lobe pattern with null. Switching apparatus is provided to connect a common terminal to either of the ports.

  9. Circularly polarized printed array antenna composed of end-fed strip dipoles and slots

    NASA Astrophysics Data System (ADS)

    Ito, K.

    1984-07-01

    Addition of an end-fed strip dipole as a strip radiator on a circularly polarized printed array antenna (CP-PASS) is shown to enhance the gain. The feed structure is similar to that of microstrip slot antennas. A wider window and tapered line side window edge allow the strip dipole edge to function as a free space dipole. An electric field along the feed line excites the strip dipole and the magnetic field induces some excitation in the window edge. A numerical model is defined for the basic element pairs of CP-PASS antenna and design procedures are derived. Experimental results from 6- and 24-pair CP-PASS prototypes demonstrate a 15 dB gain with the latter. Further gains are indicated with more optimized configurations.

  10. Theoretical and measured electric field distributions within an annular phased array: consideration of source antennas.

    PubMed

    Zhang, Y; Joines, W T; Jirtle, R L; Samulski, T V

    1993-08-01

    The magnitude of E-field patterns generated by an annular array prototype device has been calculated and measured. Two models were used to describe the radiating sources: a simple linear dipole and a stripline antenna model. The stripline model includes detailed geometry of the actual antennas used in the prototype and an estimate of the antenna current based on microstrip transmission line theory. This more detailed model yields better agreement with the measured field patterns, reducing the rms discrepancy by a factor of about 6 (from approximately 23 to 4%) in the central region of interest where the SEM is within 25% of the maximum. We conclude that accurate modeling of source current distributions is important for determining SEM distributions associated with such heating devices. PMID:8258444

  11. 802GHz integrated horn antennas imaging array

    NASA Astrophysics Data System (ADS)

    Ali-Ahmad, Walid Y.; Rebeiz, Gabriel M.; Dave, Hemant; Chin, Gordon

    1991-05-01

    Pattern measurements at 802GHz of a single element in 256-element integrated horn imaging array are presented. The integrated-horn antenna consists of a dipole-antenna suspended on a 1-micron dielectric membrane inside a pyramidal cavity etched in silicon. The theoretical far-field patterns, calculated using reciprocity and Floquet-modes representation of the free-space field, agree well with the measured far-field patterns at 802GHz. The associated directivity for a 1.40 lambda horn aperture, calculated from the measured E and H-plane patterns is 12.3dB + or - 0.2dB. This work demonstrates that high-efficiency integrated-horn antennas are easily scalable to terahertz frequencies and could be used for radio-astronomical and plasma-diagnostic applications.

  12. Demonstration of an X-Band Multilayer Yagi-Like Microstrip Patch Antenna With High Directivity and Large Bandwidth

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Zaman, Afroz; Lee, Richard Q.; Lambert, Kevin

    2005-01-01

    The feasibility of obtaining large bandwidth and high directivity from a multilayer Yagi-like microstrip patch antenna at 10 GHz is investigated. A measured 10-dB bandwidth of approximately 20 percent and directivity of approximately 11 dBi is demonstrated through the implementation of a vertically-stacked structure with three parasitic directors, above the driven patch, and a single reflector underneath the driven patch. Simulated and measured results are compared and show fairly close agreement. This antenna offers the advantages of large bandwidth, high directivity, and symmetrical broadside patterns, and could be applicable to satellite as well as terrestrial communications.

  13. Antenna engineering handbook /2nd edition/

    NASA Astrophysics Data System (ADS)

    Johnson, R. C.; Jasik, H.

    Essential principles, methods, and data for solving a wide range of problems in antenna design and application are presented. The basic concepts and fundamentals of antennas are reviewed, followed by a discussion of arrays of discrete elements. Then all primary types of antennas currently in use are considered, providing concise descriptions of operating principles, design methods, and performance data. Small antennas, microstrip antennas, frequency-scan antennas, conformal and low-profile arrays, adaptive antennas, and phased arrays are covered. The major applications of antennas and the design methods peculiar to those applications are discussed in detail. The employment of antennas to meet the requirements of today's complex electronic systems is emphasized, including earth station antennas, satellite antennas, seeker antennas, microwave-relay antennas, tracking antennas, radiometer antennas, and ECM and ESM antennas. Finally, significant topics related to antenna engineering, such as transmission lines and waveguides, radomes, microwave propagation, and impedance matching and broadbanding, are addressed.

  14. Spatially resolving antenna arrays using frequency diversity.

    PubMed

    Marks, Daniel L; Gollub, Jonah; Smith, David R

    2016-05-01

    Radio imaging devices and synthetic aperture radar typically use either mechanical scanning or phased arrays to illuminate a target with spatially varying radiation patterns. Mechanical scanning is unsuitable for many high-speed imaging applications, and phased arrays contain many active components and are technologically and cost prohibitive at millimeter and terahertz frequencies. We show that antennas deliberately designed to produce many different radiation patterns as the frequency is varied can reduce the number of active components necessary while still capturing high-quality images. This approach, called frequency-diversity imaging, can capture an entire two-dimensional image using only a single transmit and receive antenna with broadband illumination. We provide simple principles that ascertain whether a design is likely to achieve particular resolution specifications, and illustrate these principles with simulations. PMID:27140887

  15. General view of Sector Four Compound, looking north. Antenna Array ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of Sector Four Compound, looking north. Antenna Array is in background, behind Communications Antennas, Receiver Building, and Water Storage Tank - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Four Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

  16. A design concept for an MMIC (Monolithic Microwave Integrated Circuit) microstrip phased array

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Smetana, Jerry; Acosta, Roberto

    1987-01-01

    A conceptual design for a microstrip phased array with monolithic microwave integrated circuit (MMIC) amplitude and phase controls is described. The MMIC devices used are 20 GHz variable power amplifiers and variable phase shifters recently developed by NASA contractors for applications in future Ka proposed design, which concept is for a general NxN element array of rectangular lattice geometry. Subarray excitation is incorporated in the MMIC phased array design to reduce the complexity of the beam forming network and the number of MMIC components required.

  17. Coherent optical monolithic phased-array antenna steering system

    DOEpatents

    Hietala, Vincent M.; Kravitz, Stanley H.; Vawter, Gregory A.

    1994-01-01

    An optical-based RF beam steering system for phased-array antennas comprising a photonic integrated circuit (PIC). The system is based on optical heterodyning employed to produce microwave phase shifting by a monolithic PIC constructed entirely of passive components. Microwave power and control signal distribution to the antenna is accomplished by optical fiber, permitting physical separation of the PIC and its control functions from the antenna. The system reduces size, weight, complexity, and cost of phased-array antenna systems.

  18. Joint stars phased array radar antenna

    NASA Astrophysics Data System (ADS)

    Shnitkin, Harold

    1994-10-01

    The Joint STARS phased array radar system is capable of performing long range airborne surveillance and was used during the Persian Gulf war on two E8-A aircraft to fly many around-the-clock missions to monitor the Kuwait and Iraq battlefield from a safe distance behind the front lines. This paper is a follow-on to previous publications on the subject of the Joint STARS antenna and deals mainly with mission performance and technical aspects not previously covered. Radar data of troop movements and armament installations will be presented, a brief review of the antenna design is given, followed by technical discussions concerning the three-port interferometry, gain and sidelobe design approach, cost control, range test implementation and future improvements.

  19. A Compact Monopulse Radial Line Slot Array Antenna at Millimeter Wavelengths

    NASA Astrophysics Data System (ADS)

    You, Lizhi; Dou, W. B.

    2007-10-01

    This paper describes the design and performance of a radial line slot array antenna (RLSA) which generates sum or difference far field patterns. The antenna consists of rectangular waveguide to radial line transition, radial line and slot arrays etched on the upper plate of the radial line. A novel rectangular waveguide to radial line transition is designed to build up the dominate TEM mode in radial line to excite the slot arrays which are arranged in concentric rings on the upper plate of the radial line. The antenna radiates linear polarization at Ka band. Monopulse operation is obtained by a sum and difference network which is a compact eight-port comparator consisting of coplanar magic tees. The sum and difference network is waveguide structure whose loss is less than that of microstrip structure at millimeter wave lengths. The monopulse performances can be used in monopulse tracking and anti-collision application etc. Genetic algorithm (GA) is applied to optimize the parameters of the transition and antenna to obtain good performances.

  20. Multi-Channel Microstrip Transceiver Arrays Using Harmonics for High Field MR Imaging in Humans

    PubMed Central

    Wu, Bing; Wang, Chunsheng; Lu, Jonathan; Pang, Yong; Nelson, Sarah J; Vigneron, Daniel B; Zhang, Xiaoliang

    2012-01-01

    RF transceiver array design using primary and higher order harmonics for in-vivo parallel MR imaging and spectroscopic imaging is proposed. The improved electromagnetic decoupling performance, unique magnetic field distributions and high-frequency operation capabilities of higher-order harmonics of resonators would benefit transceiver arrays for parallel MRI, especially for ultrahigh field parallel MRI. To demonstrate this technique, microstrip transceiver arrays using first and second harmonic resonators were developed for human head parallel imaging at 7T. Phantom and human head images were acquired and evaluated using the GRAPPA reconstruction algorithm. The higher-order harmonic transceiver array design technique was also assessed numerically using FDTD simulation. Compared with regular primary-resonance transceiver designs, the proposed higher-order harmonic technique provided an improved g-factor and increased decoupling among resonant elements without using dedicated decoupling circuits, which would potentially lead to a better parallel imaging performance and ultimately faster and higher quality imaging. The proposed technique is particularly suitable for densely spaced transceiver array design where the increased mutual inductance among the elements becomes problematic. In addition, it also provides a simple approach to readily upgrade the channels of a conventional primary resonator microstrip array to a larger number for faster imaging. PMID:21878410

  1. A novel array antenna for MSAT applications

    NASA Technical Reports Server (NTRS)

    Bodnar, Donald G.; Rainer, B. Keith; Rahmat-Samii, Yahya

    1989-01-01

    The issue of reducing the cost of phased array vehicle antennas through the use of a lens feeding arrangement instead of phase shifters at each element is addressed. In particular, the economic viability of a mobile satellite system (MSAT) is largely dependent on the efficient use of the allocated scarce spectrum and orbit as well as the satellite power. the type of vehicle antenna used will play a critical role in achieving this efficiency. A standard design approach for an electronically steered array uses phase shifters at each element to provide beam steering. A method for reducing the required number of phase shifters by using an R-KR lens feed network is outlined. The authors briefly discuss the phase shifter approach to beam steering, examine various lens feed techniques, and describe the R-KR lens approach. The lens feed network architecture is examined, a computer model for simulation of the array is presented, and the results of analysis of a suggested design for the MSAT application are given. In addition, satellite acquisition and tracking considerations are investigated.

  2. Impulse Testing of Corporate-Fed Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil F.

    2011-01-01

    This paper discusses a novel method for detecting faults in antenna arrays. The method, termed Impulse Testing, was developed for corporate-fed patch arrays where the element is fed by a probe and is shorted at its center. Impulse Testing was devised to supplement conventional microwave measurements in order to quickly verify antenna integrity. The technique relies on exciting each antenna element in turn with a fast pulse (or impulse) that propagates through the feed network to the output port of the antenna. The resulting impulse response is characteristic of the path through the feed network. Using an oscilloscope, a simple amplitude measurement can be made to detect faults. A circuit model of the antenna elements and feed network was constructed to assess various fault scenarios and determine fault-detection thresholds. The experimental setup and impulse measurements for two patch array antennas are presented. Advantages and limitations of the technique are discussed along with applications to other antenna array topologies

  3. Patterning of visible/infrared dual-band microstrip filter arrays for multispectral imaging application

    NASA Astrophysics Data System (ADS)

    Lai, Jian-Jun; Liang, Hua-Feng; Zhou, Zhi-Ping; Fang, Guo-Jia; Li, Li

    2009-08-01

    Visible/infrared dual-band microstrip filter arrays have been developed to be integrated with 512 × 512 PtSi CCD imaging sensor chips for multispectral imaging when it operates in the front-illumination mode. A high visible transmittance and high infrared reflectance ZAO (ZnO:Al) based coating for visible passband and an interference absorbing filter film for a mid-infrared passband have been designed and deposited on sapphire substrates. An effective double-layer lift-off technique that is compatible with high temperature deposition has been developed to create thick microstrip infrared film. The infrared passband film using germanium and yttrium fluoride as high and low refractive indices materials have been deposited by ion-beam-assisted electron beam evaporation. Tested optical performance results reveal that the visible and near-infrared transmittance of the infrared passband film is very low, which makes it ideal for mid-infrared imaging. Environmental durability testing shows that the microstrip arrays have good mechanical and thermal performances for practical applications.

  4. Adaptive antenna arrays for satellite communication

    NASA Technical Reports Server (NTRS)

    Gupta, Inder J.

    1989-01-01

    The feasibility of using adaptive antenna arrays to provide interference protection in satellite communications was studied. The feedback loops as well as the sample matric inversion (SMI) algorithm for weight control were studied. Appropriate modifications in the two were made to achieve the required interference suppression. An experimental system was built to test the modified feedback loops and the modified SMI algorithm. The performance of the experimental system was evaluated using bench generated signals and signals received from TVRO geosynchronous satellites. A summary of results is given. Some suggestions for future work are also presented.

  5. Very Long Microstrip Array Feeds of a Membrane Reflector for the Advanced Precipitation Radar

    NASA Technical Reports Server (NTRS)

    Huang, John; Rahmat-Samii, Yahya; Durden, Stephen L.; Im, Eastwood

    2005-01-01

    Very long microstrip arrays have been developed at the Ku- and Ka-band frequencies. Each array having an electrical length of about 110 free-space wavelengths is used to feed a deployable thin-membrane cylindrical reflector for a spaceborne precipitation radar application. These arrays, designed for 0(deg) and 30(deg) beam directions, achieved peak sidelobes of -20 dB and average sidelobes below -30 dB with peak cross-pol levels below -20 dB. Several unique challenges were encountered during the development of these very long arrays, such as the strong coupling between very long power divider lines, the strong leakage radiation from the lengthy transmission lines, and the lack of computer analysis capability of these electrically large arrays.

  6. Twenty-GHz broadband microstrip array with electromagnetically coupled high-{Tc} superconducting feed network

    SciTech Connect

    Herd, J.S.; Poles, L.D.; Kenney, J.P.

    1996-07-01

    The use of high-temperature superconducting (HTS) feed lines and phase shifters can substantially improve the performance of microwave and millimeter-wave printed phased array antennas. A novel antenna architecture is described that provides a broadband radiating aperture to be used as a scanning array with compatible low-loss HTS phase shifters. The approach follows an earlier design demonstrated at 12 GHz, and this work extends the approach to 20 GHz. The antenna design, radiation patterns, bandwidth measurements, and thermal analysis are reported. A prototype thermal isolator design is described that reduces the heat load of coaxial interconnections between cryocooled and room temperature systems.

  7. Research in large adaptive antenna arrays

    NASA Technical Reports Server (NTRS)

    Berkowitz, R. S.; Dzekov, T.

    1976-01-01

    The feasibility of microwave holographic imaging of targets near the earth using a large random conformal array on the earth's surface and illumination by a CW source on a geostationary satellite is investigated. A geometrical formulation for the illuminator-target-array relationship is applied to the calculation of signal levels resulting from L-band illumination supplied by a satellite similar to ATS-6. The relations between direct and reflected signals are analyzed and the composite resultant signal seen at each antenna element is described. Processing techniques for developing directional beam formation as well as SNR enhancement are developed. The angular resolution and focusing characteristics of a large array covering an approximately circular area on the ground are determined. The necessary relations are developed between the achievable SNR and the size and number of elements in the array. Numerical results are presented for possible air traffic surveillance system. Finally, a simple phase correlation experiment is defined that can establish how large an array may be constructed.

  8. Grounded Coplanar Waveguide Feeds Phased-Array Antenna

    NASA Technical Reports Server (NTRS)

    Ponchak, G.E.; Lee, R. Q.; Simons, R. N.; Fernandez, N.S.

    1993-01-01

    Prototype electronically steerable K-band end-fire antenna includes phased array of four printed-circuit linear dipole elements fed by grounded coplanar waveguide (GCPW). Distribution-and-phasing network of antenna fed through single entering antenna split equally by three GCPW T junctions onto four GCPW transmission lines.

  9. Characterization of transceive surface element designs for 7 tesla magnetic resonance imaging of the prostate: radiative antenna and microstrip

    NASA Astrophysics Data System (ADS)

    Ipek, Ö.; Raaijmakers, A. J. E.; Klomp, D. W. J.; Lagendijk, J. J. W.; Luijten, P. R.; van den Berg, C. A. T.

    2012-01-01

    Ultra-high field magnetic resonance (⩾7 tesla) imaging (MRI) faces challenges with respect to efficient spin excitation and signal reception from deeply situated organs. Traditional radio frequency surface coil designs relying on near-field coupling are suboptimal at high field strengths. Better signal penetration can be obtained by designing a radiative antenna in which the energy flux is directed to the target location. In this paper, two different radiative antenna designs are investigated to be used as transceive elements, which employ different dielectric permittivities for the antenna substrate. Their transmit and receive performances in terms of B+1, local SAR (specific absorption rate) and SNR (signal-to-noise ratio) were compared using extensive electromagnetic simulations and MRI measurements with traditional surface microstrip coils. Both simulations and measurements demonstrated that the radiative element shows twofold gain in B+1 and SNR at 10 cm depth, and additionally a comparable SAR peak value. In terms of transmit performance, the radiative antenna with a dielectric permittivity of 37 showed a 24% more favorable local SAR10g avg/(B+1)2 ratio than the radiative antenna with a dielectric permittivity of 90. In receive, the radiative element with a dielectric permittivity of 90 resulted in a 20% higher SNR for shallow depths, but for larger depths this difference diminished compared to the radiative element with a dielectric permittivity of 37. Therefore, to image deep anatomical regions effectively, the radiative antenna with a dielectric permittivity of 37 is favorable.

  10. Characterization of transceive surface element designs for 7 tesla magnetic resonance imaging of the prostate: radiative antenna and microstrip.

    PubMed

    Ipek, O; Raaijmakers, A J E; Klomp, D W J; Lagendijk, J J W; Luijten, P R; van den Berg, C A T

    2012-01-21

    Ultra-high field magnetic resonance (≥7 tesla) imaging (MRI) faces challenges with respect to efficient spin excitation and signal reception from deeply situated organs. Traditional radio frequency surface coil designs relying on near-field coupling are suboptimal at high field strengths. Better signal penetration can be obtained by designing a radiative antenna in which the energy flux is directed to the target location. In this paper, two different radiative antenna designs are investigated to be used as transceive elements, which employ different dielectric permittivities for the antenna substrate. Their transmit and receive performances in terms of B(+)(1), local SAR (specific absorption rate) and SNR (signal-to-noise ratio) were compared using extensive electromagnetic simulations and MRI measurements with traditional surface microstrip coils. Both simulations and measurements demonstrated that the radiative element shows twofold gain in B(+)(1) and SNR at 10 cm depth, and additionally a comparable SAR peak value. In terms of transmit performance, the radiative antenna with a dielectric permittivity of 37 showed a 24% more favorable local SAR(10g avg)/(B(+)(1))(2) ratio than the radiative antenna with a dielectric permittivity of 90. In receive, the radiative element with a dielectric permittivity of 90 resulted in a 20% higher SNR for shallow depths, but for larger depths this difference diminished compared to the radiative element with a dielectric permittivity of 37. Therefore, to image deep anatomical regions effectively, the radiative antenna with a dielectric permittivity of 37 is favorable. PMID:22170777

  11. Cantilever RF-MEMS for monolithic integration with phased array antennas on a PCB

    NASA Astrophysics Data System (ADS)

    Aguilar-Armenta, C. J.; Porter, S. J.

    2015-12-01

    This article presents the development and operation of a novel electrostatic metal-to-metal contact cantilever radio-frequency microelectromechanical system (RF-MEMS) switch for monolithic integration with microstrip phased array antennas (PAAs) on a printed circuit board. The switch is fabricated using simple photolithography techniques on a Rogers 4003c substrate, with a footprint of 200 µm × 100 µm, based on a 1 µm-thick copper cantilever. An alternative wet-etching technique for effectively releasing the cantilever is described. Electrostatic and electromagnetic measurements show that the RF-MEMS presents an actuation voltage of 90 V for metal-to-metal contact, an isolation of -8.7 dB, insertion loss of -2.5 dB and a return loss of -15 dB on a 50 Ω microstrip line at 12.5 GHz. For proof-of-concept, a beam-steering 2 × 2 microstrip PAA, based on two 1-bit phase shifters suitable for the monolithic integration of the RF-MEMS, has been designed and measured at 12.5 GHz. Measurements show that the beam-steering system presents effective radiation characteristics with scanning capabilities from broadside towards 29° in the H-plane.

  12. Infrared technology for satellite power conversion. [antenna arrays and bolometers

    NASA Technical Reports Server (NTRS)

    Campbell, D. P.; Gouker, M. A.; Gallagher, J. J.

    1984-01-01

    Successful fabrication of bismuth bolometers led to the observation of antenna action rom array elements. Fabrication of the best antennas arrays was made more facile with finding that increased argon flow during the dc sputtering produced more uniform bismuth films and bonding to antennas must be done with the substrate temperaure below 100 C. Higher temperatures damaged the bolometers. During the testing of the antennas, it was found that the use of a quasi-optical system provided a uniform radiation field. Groups of antennas were bonded in series and in parallel with the parallel configuration showing the greater response.

  13. S-band antenna phased array communications system

    NASA Technical Reports Server (NTRS)

    Delzer, D. R.; Chapman, J. E.; Griffin, R. A.

    1975-01-01

    The development of an S-band antenna phased array for spacecraft to spacecraft communication is discussed. The system requirements, antenna array subsystem design, and hardware implementation are examined. It is stated that the phased array approach offers the greatest simplicity and lowest cost. The objectives of the development contract are defined as: (1) design of a medium gain active phased array S-band communications antenna, (2) development and test of a model of a seven element planar array of radiating elements mounted in the appropriate cavity matrix, and (3) development and test of a breadboard transmit/receive microelectronics module.

  14. MSAT-X phased array antenna adaptions to airborne applications

    NASA Technical Reports Server (NTRS)

    Sparks, C.; Chung, H. H.; Peng, S. Y.

    1988-01-01

    The Mobile Satellite Experiment (MSAT-X) phased array antenna is being modified to meet future requirements. The proposed system consists of two high gain antennas mounted on each side of a fuselage, and a low gain antenna mounted on top of the fuselage. Each antenna is an electronically steered phased array based on the design of the MSAT-X antenna. A beamforming network is connected to the array elements via coaxial cables. It is essential that the proposed antenna system be able to provide an adequate communication link over the required space coverage, which is 360 degrees in azimuth and from 20 degrees below the horizon to the zenith in elevation. Alternative design concepts are suggested. Both open loop and closed loop backup capabilities are discussed. Typical antenna performance data are also included.

  15. Magnetic current loop array in a reflector antenna

    NASA Astrophysics Data System (ADS)

    Yung, Edward K. N.; Lee, Wilson W. S.

    1994-04-01

    A magnetic current loop antenna array is designed, implemented, and measured. Radiation pattern, input impedance, and efficiency of the array are presented. The array is intended as a feed in a reflector antenna. Using a 360 mm solid dish, the overall gain of the reflector antenna is 24.6 dB at 9 GHz. The tolerance in placing the feed at the focal point of the dish is high. The present feed is low cost, self-supportive, robust, and easy to manufacture. It is an ideal substitute for the horn in a TVRO (television receive only) or VSAT (very small aperature terminal) antenna.

  16. Absorbed Power Minimization in Cellular Users with Circular Antenna Arrays

    NASA Astrophysics Data System (ADS)

    Christofilakis, Vasilis; Votis, Constantinos; Tatsis, Giorgos; Raptis, Vasilis; Kostarakis, Panos

    2010-01-01

    Nowadays electromagnetic pollution of non ionizing radiation generated by cellular phones concerns millions of people. In this paper the use of circular antenna array as a means of minimizing the absorbed power by cellular phone users is introduced. In particular, the different characteristics of radiation patterns produced by a helical conventional antenna used in mobile phones operating at 900 MHz and those produced by a circular antenna array, hypothetically used in the same mobile phones, are in detail examined. Furthermore, the percentage of decrement of the power absorbed in the head as a function of direction of arrival is estimated for the circular antenna array.

  17. Electromagnetic scattering and radiation from microstrip patch antennas and spirals residing in a cavity

    NASA Technical Reports Server (NTRS)

    Volakis, J. L.; Gong, J.; Alexanian, A.; Woo, A.

    1992-01-01

    A new hybrid method is presented for the analysis of the scattering and radiation by conformal antennas and arrays comprised of circular or rectangular elements. In addition, calculations for cavity-backed spiral antennas are given. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at O(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of large-size structures with remarkable efficiency. In this report, we describe the method's formulation and implementation for circular and rectangular patch antennas in different superstrate and substrate configurations which may also include the presence of lumped loads and resistive sheets/cards. Also, various modelling approaches are investigated and implemented for characterizing a variety of feed structures to permit the computation of the input impedance and radiation pattern. Many computational examples for rectangular and circular patch configurations are presented which demonstrate the method's versatility, modeling capability and accuracy.

  18. Silicon Micromachined Microlens Array for THz Antennas

    NASA Technical Reports Server (NTRS)

    Lee, Choonsup; Chattopadhyay, Goutam; Mehdi, IImran; Gill, John J.; Jung-Kubiak, Cecile D.; Llombart, Nuria

    2013-01-01

    5 5 silicon microlens array was developed using a silicon micromachining technique for a silicon-based THz antenna array. The feature of the silicon micromachining technique enables one to microfabricate an unlimited number of microlens arrays at one time with good uniformity on a silicon wafer. This technique will resolve one of the key issues in building a THz camera, which is to integrate antennas in a detector array. The conventional approach of building single-pixel receivers and stacking them to form a multi-pixel receiver is not suited at THz because a single-pixel receiver already has difficulty fitting into mass, volume, and power budgets, especially in space applications. In this proposed technique, one has controllability on both diameter and curvature of a silicon microlens. First of all, the diameter of microlens depends on how thick photoresist one could coat and pattern. So far, the diameter of a 6- mm photoresist microlens with 400 m in height has been successfully microfabricated. Based on current researchers experiences, a diameter larger than 1-cm photoresist microlens array would be feasible. In order to control the curvature of the microlens, the following process variables could be used: 1. Amount of photoresist: It determines the curvature of the photoresist microlens. Since the photoresist lens is transferred onto the silicon substrate, it will directly control the curvature of the silicon microlens. 2. Etching selectivity between photoresist and silicon: The photoresist microlens is formed by thermal reflow. In order to transfer the exact photoresist curvature onto silicon, there needs to be etching selectivity of 1:1 between silicon and photoresist. However, by varying the etching selectivity, one could control the curvature of the silicon microlens. The figure shows the microfabricated silicon microlens 5 x5 array. The diameter of the microlens located in the center is about 2.5 mm. The measured 3-D profile of the microlens surface has a

  19. Using Antenna Arrays to Motivate the Study of Sinusoids

    ERIC Educational Resources Information Center

    Becker, J. P.

    2010-01-01

    Educational activities involving antenna arrays to motivate the study of sinusoids are described. Specifically, using fundamental concepts related to phase and simple geometric arguments, students are asked to predict the location of interference nulls in the radiation pattern of two-element phased array antennas. The location of the radiation…

  20. View to the southwest of the antenna array, note the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the southwest of the antenna array, note the site fence in the foreground - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Four Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  1. Small X-Band Oscillator Antennas

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Miranda, Felix A.; Clark, Eric B.; Wilt, David M.; Mueller, Carl H.; Kory, Carol L.; Lambert, Kevin M.

    2009-01-01

    A small, segmented microstrip patch antenna integrated with an X-band feedback oscillator on a high-permittivity substrate has been built and tested. This oscillator antenna is a prototype for demonstrating the feasibility of such devices as compact, low-power-consumption building blocks of advanced, lightweight, phased antenna arrays that would generate steerable beams for communication and remotesensing applications.

  2. Remoting alternatives for a multiple phased-array antenna network

    NASA Astrophysics Data System (ADS)

    Shi, Zan; Foshee, James J.

    2001-10-01

    Significant improvements in technology have made phased array antennas an attractive alternative to the traditional dish antenna for use on wide body airplanes. These improvements have resulted in reduced size, reduced cost, reduced losses in the transmit and receive channels (simplifying the design), a significant extension in the bandwidth capability, and an increase in the functional capability. Flush mounting (thus reduced drag) and rapid beam switching are among the evolving desirable features of phased array antennas. Beam scanning of phased array antennas is limited to +/-45 degrees at best and therefore multiple phased array antennas would need to be used to insure instantaneous communications with any ground station (stations located at different geographical locations on the ground) and with other airborne stations. The exact number of phased array antennas and the specific installation location of each antenna on the wide body airplane would need to be determined by the specific communication requirements, but it is conceivable as many as five phased array antennas may need to be used to provide the required coverage. Control and switching of these antennas would need to be accomplished at a centralized location on the airplane and since these antennas would be at different locations on the airplane an efficient scheme of remoting would need to be used. To save in cost and keep the phased array antennas as small as possible the design of the phased array antennas would need to be kept simple. A dish antenna and a blade antenna (small size) could also be used to augment the system. Generating the RF signals at the central location and then using RF cables or waveguide to get the signal to any given antenna could result in significant RF losses. This paper will evaluate a number of remoting alternatives to keep the system design simple, reduce system cost, and utilize the functional capability of networking multiple phased array antennas on a wide body

  3. Analysis of reconfigurable line pattern of capillary plasma antenna array

    NASA Astrophysics Data System (ADS)

    Ramli, Noor Fadhilah; Dagang, Ahmad Nazri; Ali, Mohd Tarmizi

    2015-04-01

    Simulations by applying Computer Simulation Technology (CST) Microwave Studio have been done towards Hg-Ar (10 Torr and 20 Torr) capillary tubes. These capillary tubes which are 5 mm in diameter are designed as plasma antenna monopole antenna and antenna arrays (four line array, six line array and nine line array). They have been arranged in the two different dimensions, 4mm × 4mm and 8mm × 8mm. Their performance as an antenna have been analyzed and compared. The reconfigurable characteristics of these kinds of plasma antenna such as gain, directivity and return loss are calculated. The results of gain and directivity of 10 Torr of plasma antenna are stronger than 20 Torr in the 4mm × 4mm dimension. Return loss of these kinds of plasma antenna significantly dropped in different operating frequencies of microwave ranges make them suitable to be applied for multiple applications in antennas or telecommunications field. Gas pressure of plasma antenna and array distance between the capillary tubes give a significant effect to the antenna performance in range of 10 GHz and below.

  4. Development of impedance matching technologies for ICRF antenna arrays

    SciTech Connect

    Pinsker, R.I.

    1998-03-01

    All high power ICRF heating systems include devices for matching the input impedance of the antenna array to the generator output impedance. For most types of antennas used, the input impedance is strongly time-dependent on timescales as rapid as 10-4 s, while the rf generators used are capable of producing full power only into a stationary load impedance. Hence, the dynamic response of the matching method is of great practical importance. In this paper, world-wide developments in this field over the past decade are reviewed. These techniques may be divided into several classes. The edge plasma parameters that determine the antenna array`s input impedance may be controlled to maintain a fixed load impedance. The frequency of the rf source can be feedback controlled to compensate for changes in the edge plasma conditions, or fast variable tuning elements in the transmission line between the generator output and the antenna input connections can provide the necessary time-varying impedance transformation. In lossy passive schemes, reflected power due to the time-varying impedance of the antenna array is diverted to a dummy load. Each of these techniques can be applied to a pre-existing antenna system. If a new antenna is to be designed, recent advances allow the antenna array to have the intrinsic property of presenting a constant load to the feeding transmission lines despite the varying load seen by each antenna in the array.

  5. Antenna research and development at Ericsson

    NASA Astrophysics Data System (ADS)

    Dahlsjo, Olof

    1992-04-01

    This article gives an overview of the antenna research and development activities at Ericsson Radar Electronics AB, in Molndal, Sweden. The article covers different types of microwave antennas, such as twist-Cassegrain antennas, shaped-reflector antennas, microstrip antennas, dichroic surfaces, slotted-waveguide-array antennas, omnidirectional antennas, and electronically-steered-array antennas. Measurement methods, such as near-field and diagnostic techniques, are also discussed. The applications are for radar and microwave communication systems, for use in ground, naval, airborne, and space environments.

  6. Effect of photonic crystal and frequency selective surface implementation on gain enhancement in the microstrip patch antenna at terahertz frequency

    NASA Astrophysics Data System (ADS)

    Nejati, Ameneh; Sadeghzadeh, Ramezan Ali; Geran, Fatemeh

    2014-09-01

    In this paper, microstrip patch antenna with frequency selective surface (FSS) and photonic band gap (PBG) structures in the frequency range of 0.5-0.7 THz is presented for wireless communications. Proposed patch antenna is designed on a substrate with uniform and non-uniform PBG structures. Here, the effects of substrate thickness, various radii and arrangement of holes on antenna resonance in both PBG forms are studied. Near zero characteristic on uniform and non-uniform PBG substrate is compared and the results show that along with increase in hole radius, antenna operating frequency and bandwidth are increased. Also, the FSS structure is designed as a perfect absorber. Finally, by using FSS and PBG structures simultaneously, gain enhancement, increase in directivity and pattern shaping are studied at THz field. The antenna gain in final structure is increased by 2 dBi (32%) in comparison to simple form and Half-Power beam width is reduced from 100°×80° in simple form to 72°×48° by using FSS and PBG. All simulations and designs are done by Ansoft HFSS and CST Microwave Studio simulation tools with different full wave methods.

  7. Prediction of Slot Shape and Slot Size for Improving the Performance of Microstrip Antennas Using Knowledge-Based Neural Networks

    PubMed Central

    De, Asok

    2014-01-01

    In the last decade, artificial neural networks have become very popular techniques for computing different performance parameters of microstrip antennas. The proposed work illustrates a knowledge-based neural networks model for predicting the appropriate shape and accurate size of the slot introduced on the radiating patch for achieving desired level of resonance, gain, directivity, antenna efficiency, and radiation efficiency for dual-frequency operation. By incorporating prior knowledge in neural model, the number of required training patterns is drastically reduced. Further, the neural model incorporated with prior knowledge can be used for predicting response in extrapolation region beyond the training patterns region. For validation, a prototype is also fabricated and its performance parameters are measured. A very good agreement is attained between measured, simulated, and predicted results. PMID:27382616

  8. Prediction of Slot Shape and Slot Size for Improving the Performance of Microstrip Antennas Using Knowledge-Based Neural Networks.

    PubMed

    Khan, Taimoor; De, Asok

    2014-01-01

    In the last decade, artificial neural networks have become very popular techniques for computing different performance parameters of microstrip antennas. The proposed work illustrates a knowledge-based neural networks model for predicting the appropriate shape and accurate size of the slot introduced on the radiating patch for achieving desired level of resonance, gain, directivity, antenna efficiency, and radiation efficiency for dual-frequency operation. By incorporating prior knowledge in neural model, the number of required training patterns is drastically reduced. Further, the neural model incorporated with prior knowledge can be used for predicting response in extrapolation region beyond the training patterns region. For validation, a prototype is also fabricated and its performance parameters are measured. A very good agreement is attained between measured, simulated, and predicted results. PMID:27382616

  9. An algorithm for the empirical optimization of antenna arrays

    NASA Technical Reports Server (NTRS)

    Blank, S.

    1983-01-01

    A numerical technique is presented to optimize the performance of arbitrary antenna arrays under realistic conditions. An experimental-computational algorithm is formulated in which n-dimensional minimization methods are applied to measured data obtained from the antenna array. A numerical update formula is used to induce partial derivative information without requiring special perturbations of the array parameters. The algorithm provides a new design for the antenna array, and the method proceeds in an iterative fashion. Test case results are presented showing the effectiveness of the algorithm.

  10. Compensation of relector antenna surface distortion using an array feed

    NASA Technical Reports Server (NTRS)

    Cherrette, A. R.; Acosta, R. J.; Lam, P. T.; Lee, S. W.

    1988-01-01

    The dimensional stability of the surface of a large reflector antenna is important when high gain or low sidelobe performance is desired. If the surface is distorted due to thermal or structural reasons, antenna performance can be improved through the use of an array feed. The design of the array feed and its relation to the surface distortion are examined. The sensitivity of antenna performance to changing surface parameters for fixed feed array geometries is also studied. This allows determination of the limits of usefulness for feed array compensation.

  11. Compensation of reflector antenna surface distortion using an array feed

    NASA Technical Reports Server (NTRS)

    Cherrette, Alan R.; Acosta, Roberto J.; Lam, Peter T.; Lee, Shung-Wu

    1989-01-01

    The dimensional stability of the surface of a large reflector antenna is important when high gain or low sidelobe performance is desired. If the surface is distorted due to thermal or structural reasons, antenna performance can be improved through the use of an array feed. The design of the array feed and its relation to the surface distortion are examined. The sensitivity of antenna performance to changing surface parameters for fixed feed array geometries is also studied. This allows determination of the limits of usefulness for feed array compensation.

  12. Antennas for diverse requirements

    NASA Astrophysics Data System (ADS)

    Boukamp, Joachim

    An account is given of a major German aerospace manufacturer's state-of-the-art methods for development, design, construction, testing and certification of a wide variety of civilian and military communications and radar antennas. Attention is given to reflector antennas for very large aperture/wavelength ratios, slotted waveguide arrays in which the radiating aperture is synthesized by guided structures, and both microstrip arrays and active arrays, for the creation of very large area antennas. Antenna tests and measurements are conducted in an anechoic chamber.

  13. Technique for Radiometer and Antenna Array Calibration with Two Antenna Noise Diodes

    NASA Technical Reports Server (NTRS)

    Srinivasan, Karthik; Limaye, Ashutosh; Laymon, Charles; Meyer, Paul

    2011-01-01

    This paper presents a new technique to calibrate a microwave radiometer and phased array antenna system. This calibration technique uses a radiated noise source in addition to an injected noise sources for calibration. The plane of reference for this calibration technique is the face of the antenna and therefore can effectively calibration the gain fluctuations in the active phased array antennas. This paper gives the mathematical formulation for the technique and discusses the improvements brought by the method over the existing calibration techniques.

  14. Electronic Switching Spherical Array (ESSA) antenna systems

    NASA Technical Reports Server (NTRS)

    Hockensmith, R. P.

    1984-01-01

    ESSA (Electronic Switching Spherical Array) is an antenna system conceived, developed and qualified for linking satellite data transmissions with NASA's tracking and data relay satellites (TDRSS) and tracking and data acquisition satellites (TDAS). ESSA functions in the S band frequency region, cover 2 pi or more steradians with directional gain and operates in multiple selectable modes. ESSA operates in concert with the NASA's TDRS standard transponder in the retrodirective mode or independently in directional beam, program track and special modes. Organizations and projects to the ESSA applications for NASA's space use are introduced. Coverage gain, weight power and implementation and other performance information for satisfying a wide range of data rate requirements are included.

  15. A phased antenna array for surface plasmons.

    PubMed

    Dikken, Dirk Jan W; Korterik, Jeroen P; Segerink, Frans B; Herek, Jennifer L; Prangsma, Jord C

    2016-01-01

    Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an optical frequency plasmonic analog to the phased antenna array as it is well known in radar technology and radio astronomy. Individual holes in a thick gold film act as dipolar emitters of surface plasmon polaritons whose phase is controlled individually using a digital spatial light modulator. We show experimentally, using a phase sensitive near-field microscope, that this optical system allows accurate directional emission of surface waves. This compact and flexible method allows for dynamically shaping the propagation of plasmons and holds promise for nanophotonic applications employing propagating surface plasmons. PMID:27121099

  16. A phased antenna array for surface plasmons

    NASA Astrophysics Data System (ADS)

    Dikken, Dirk Jan W.; Korterik, Jeroen P.; Segerink, Frans B.; Herek, Jennifer L.; Prangsma, Jord C.

    2016-04-01

    Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an optical frequency plasmonic analog to the phased antenna array as it is well known in radar technology and radio astronomy. Individual holes in a thick gold film act as dipolar emitters of surface plasmon polaritons whose phase is controlled individually using a digital spatial light modulator. We show experimentally, using a phase sensitive near-field microscope, that this optical system allows accurate directional emission of surface waves. This compact and flexible method allows for dynamically shaping the propagation of plasmons and holds promise for nanophotonic applications employing propagating surface plasmons.

  17. A phased antenna array for surface plasmons

    PubMed Central

    Dikken, Dirk Jan W.; Korterik, Jeroen P.; Segerink, Frans B.; Herek, Jennifer L.; Prangsma, Jord C.

    2016-01-01

    Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an optical frequency plasmonic analog to the phased antenna array as it is well known in radar technology and radio astronomy. Individual holes in a thick gold film act as dipolar emitters of surface plasmon polaritons whose phase is controlled individually using a digital spatial light modulator. We show experimentally, using a phase sensitive near-field microscope, that this optical system allows accurate directional emission of surface waves. This compact and flexible method allows for dynamically shaping the propagation of plasmons and holds promise for nanophotonic applications employing propagating surface plasmons. PMID:27121099

  18. Fully Printed, Flexible, Phased Array Antenna for Lunar Surface Communication

    NASA Technical Reports Server (NTRS)

    Subbaraman, Harish; Hen, Ray T.; Lu, Xuejun; Chen, Maggie Yihong

    2013-01-01

    NASAs future exploration missions focus on the manned exploration of the Moon, Mars, and beyond, which will rely heavily on the development of a reliable communications infrastructure from planetary surface-to-surface, surface-to-orbit, and back to Earth. Flexible antennas are highly desired in many scenarios. Active phased array antennas (active PAAs) with distributed control and processing electronics at the surface of an antenna aperture offer numerous advantages for radar communications. Large-area active PAAs on flexible substrates are of particular interest in NASA s space radars due to their efficient inflatable package that can be rolled up during transportation and deployed in space. Such an inflatable package significantly reduces stowage volume and mass. Because of these performance and packaging advantages, large-area inflatable active PAAs are highly desired in NASA s surface-to-orbit and surface-to-relay communications. To address the issues of flexible electronics, a room-temperature printing process of active phased-array antennas on a flexible Kapton substrate was developed. Field effect transistors (FETs) based on carbon nanotubes (CNTs), with many unique physical properties, were successfully proved feasible for the PAA system. This innovation is a new type of fully inkjet-printable, two-dimensional, high-frequency PAA on a flexible substrate at room temperature. The designed electronic circuit components, such as the FET switches in the phase shifter, metal interconnection lines, microstrip transmission lines, etc., are all printed using a special inkjet printer. Using the developed technology, entire 1x4, 2x2, and 4x4 PAA systems were developed, packaged, and demonstrated at 5.3 GHz. Several key solutions are addressed in this work to solve the fabrication issues. The source/drain contact is developed using droplets of silver ink printed on the source/drain areas prior to applying CNT thin-film. The wet silver ink droplets allow the silver to

  19. The Submillimeter Array Antennas and Receivers

    NASA Astrophysics Data System (ADS)

    Blundell, R.

    The Submillimeter Array (SMA) was conceived at the Smithsonian Astrophysical Observatory in 1984 as a six element interferometer to operate in the major atmospheric windows from about 200 to 900 GHz. In 1996, the Academica Sinica Institute of Astronomy and Astrophysics of Taiwan joined the project and agreed to provide additional hardware to expand the interferometer to eight elements. All eight antennas are now operating at the observatory site on Mauna Kea, and astronomical observations have been made in the 230, 345, and 650 GHz bands. The SMA antennas have a diameter of 6 m, a surface accuracy of better than 25 micron rms, and can be reconfigured to provide spatial resolutions down to about 0.5" at 200 GHz and, eventually, 0.1" at 850 GHz. Coupling to the receiver package within each antenna is achieved via a beam waveguide, in a bent Nasmyth configuration, comprised of a flat tertiary mirror and two ellipsoidal mirrors that form a secondary pupil used for receiver calibration. An additional fixed mirror and a rotating wire grid polarizer are then used for receiver selection. Each antenna houses a single cryostat, with an integrated cryocooler capable of cooling up to eight receivers to 4 K. In the current configuration only three receiver bands are available: 175-255 GHz, 250-350 GHz, and 600-720 GHz, and simultaneous operation of the 650 GHz receiver with either of the lower frequency receivers is possible. Eventually dual polarization will be available from 325-350 GHz, and dual frequency operation will be possible, pairing either of the lower frequency receivers with any of the high frequency units: 325-425 GHz, 425-510 GHz, 600-720 GHz, and 800-900 GHz. Each receiver currently uses a single superconductor-insulator-superconductor junction as the mixing element, and has first stage intermediate frequency amplification at 4 K with an instantaneous bandwidth of 2.5 GHz, centered at 5 GHz. The mixers are of a fixed-tuned waveguide design, are inherently broad

  20. Design and analysis of annular antenna arrays with different reflectors.

    PubMed

    Shi, G; Joines, W T

    2004-09-01

    The design and performance of annular antenna arrays with reflectors is presented. Arrays with three shapes of reflectors are analysed and simulated. These include the corner reflector, the circular reflector and the elliptical reflector. Power-density distributions within the annular arrays with and without reflectors are obtained by using the FDTD method. Also, the image theory method is used to verify the FDTD results in one case. By comparing the power-density distribution pattern of all four of the array designs (three with different reflectors, one without reflector), it is readily seen in each case that the array with reflectors yields better power-efficiency than the array without reflectors and the elliptical reflector yields the best performance. Comparisons of each array are made using 4, 6 and 8 antennae in the annular array. By using the optimized results of the elliptical reflector, the requirement for the input-power level to each antenna is greatly reduced. PMID:15370818

  1. Photonic Links for High-Performance Arraying of Antennas

    NASA Technical Reports Server (NTRS)

    Huang, Shouhua; Tjoelker, Robert

    2009-01-01

    An architecture for arraying microwave antennas in the next generation of NASA s Deep Space Network (DSN) involves the use of all photonic links between (1) the antennas in a given array and (2) a signal processing center. In this architecture, all affected parts at each antenna pedestal [except a front-end low-noise amplifier for the radio-frequency (RF) signal coming from the antenna and an optical transceiver to handle monitor and control (M/C) signals] would be passive optical parts

  2. Integrated Solar-Panel Antenna Array for CubeSats

    NASA Technical Reports Server (NTRS)

    Baktur, Reyhan

    2016-01-01

    The goal of the Integrated Solar-Panel Antenna Array for CubeSats (ISAAC) project is to design and demonstrate an effective and efficien toptically transparent, high-gain, lightweight, conformal X-band antenna array that is integrated with the solar panels of a CubeSat. The targeted demonstration is for a Near Earth Network (NEN)radio at X-band, but the design can be easilyscaled to other network radios for higher frequencies. ISAAC is a less expensive and more flexible design for communication systemscompared to a deployed dish antenna or the existing integrated solar panel antenna design.

  3. Study of the characteristics of reconfigurable plasma antenna array

    NASA Astrophysics Data System (ADS)

    Alias, Nur Salihah; Dagang, Ahmad Nazri; Ali, Mohd Tarmizi

    2015-04-01

    This paper presents a design and simulation of a reconfigurable array of plasma antenna. The plasma column is used as radiating elements instead of metal to create an antenna. The advantages of the plasma antenna over the conventional antenna are its possible to change the operating parameters, such as the working pressure, input power, radius of the discharge tube, resonant frequency, and length of the plasma column. In addition, plasma antenna can be reconfigurable with respect to shape, frequency and radiation parameters in a very short time. The plasma discharge tube was designed with a length of 200 mm, the radius of the plasma column was 2.5 mm and the coupling sleeve was connected to the SMA as the ground. This simulation was performed by using the simulation software Computer Simulation Technology (CST). The frequency is set in the range of 1 GHz to 10 GHz. The performance of the designed antenna was analyzed in term of return loss, gain and radiation pattern. For reconfigurable plasma antenna array, it shows that the gain is increase when the number of antenna element is increase. The combination of the discharge tube and metal rod as an antenna array has been done, and the result shows that an array with the plasma element can achieve higher gain.

  4. Study of the characteristics of reconfigurable plasma antenna array

    SciTech Connect

    Alias, Nur Salihah; Dagang, Ahmad Nazri; Ali, Mohd Tarmizi

    2015-04-24

    This paper presents a design and simulation of a reconfigurable array of plasma antenna. The plasma column is used as radiating elements instead of metal to create an antenna. The advantages of the plasma antenna over the conventional antenna are its possible to change the operating parameters, such as the working pressure, input power, radius of the discharge tube, resonant frequency, and length of the plasma column. In addition, plasma antenna can be reconfigurable with respect to shape, frequency and radiation parameters in a very short time. The plasma discharge tube was designed with a length of 200 mm, the radius of the plasma column was 2.5 mm and the coupling sleeve was connected to the SMA as the ground. This simulation was performed by using the simulation software Computer Simulation Technology (CST). The frequency is set in the range of 1 GHz to 10 GHz. The performance of the designed antenna was analyzed in term of return loss, gain and radiation pattern. For reconfigurable plasma antenna array, it shows that the gain is increase when the number of antenna element is increase. The combination of the discharge tube and metal rod as an antenna array has been done, and the result shows that an array with the plasma element can achieve higher gain.

  5. A colocated magnetic loop, electric dipole array antenna (preliminary results)

    NASA Astrophysics Data System (ADS)

    Overfelt, P. L.; Bowling, D. R.; White, D. J.

    1994-09-01

    We present a detailed electromagnetic analysis of an electrically small colocated electric dipole and magnetic loop antenna array. This antenna is the simplest example of the Grimes multipole class of antenna arrays. We have determined that since the interaction term between the two elements disappears from the radial complex power, we were able to set the radial reactance to zero by choosing appropriate current magnitudes and phases on the array elements. By driving the two elements in quadrature, we obtained a much increased radiation intensity and directivity as well as increased radiated power.

  6. Array antennas design in dependence of element-phasing

    NASA Astrophysics Data System (ADS)

    Zichner, R.; Chandra, M.

    2009-05-01

    Array antennas are used in science as well as for commercial and military purposes. The used element antennas act in accordance to their desired uses, for example radars or stationer GPS satellites. Typical components are for example slotted waveguides, patches, yagi-antennas and helix-antennas. All these elements do stand out with their own characteristics based on their special applications. If these elements are formed into an array configuration, the effectiveness can be improved immensely. There is a relation between the array functions and the physical array properties like the element alignment (linear, planar, circular), distances between the elements and so on. Among the physical properties there are other attributes like phase or amplitude coefficients, which are of great significance. The aim of this study was to provide an insight into the problem of array design, as far as the antenna element phase is concerned. Along with this, array radiation characteristics effects are presented. With the help of the extracted cognitions beam forming behaviour can be shown and the array phase behaviour can be analysed. One of the main applications is to simulate the array characteristics, like the radiation characteristic or the gain, for displacements of the array feeding point. A software solution that simulates the phase shift of a given array pattern is sought to adjust the feeding point.

  7. Optical phased arrays with evanescently-coupled antennas

    DOEpatents

    Sun, Jie; Watts, Michael R; Yaacobi, Ami; Timurdogan, Erman

    2015-03-24

    An optical phased array formed of a large number of nanophotonic antenna elements can be used to project complex images into the far field. These nanophotonic phased arrays, including the nanophotonic antenna elements and waveguides, can be formed on a single chip of silicon using complementary metal-oxide-semiconductor (CMOS) processes. Directional couplers evanescently couple light from the waveguides to the nanophotonic antenna elements, which emit the light as beams with phases and amplitudes selected so that the emitted beams interfere in the far field to produce the desired pattern. In some cases, each antenna in the phased array may be optically coupled to a corresponding variable delay line, such as a thermo-optically tuned waveguide or a liquid-filled cell, which can be used to vary the phase of the antenna's output (and the resulting far-field interference pattern).

  8. An adaptive array antenna for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Milne, Robert

    1990-01-01

    The design of an adaptive array antenna for land vehicle operation and its performance in an operational satellite system is described. Linear and circularly polarized antenna designs are presented. The acquisition and tracking operation of a satellite is described and the effect on the communications signal is discussed. A number of system requirements are examined that have a major impact on the antenna design. The results of environmental, power handling, and RFI testing are presented and potential problems are identified.

  9. Reproducible, high performance patch antenna array apparatus and method of fabrication

    DOEpatents

    Strassner, II, Bernd H.

    2007-01-23

    A reproducible, high-performance patch antenna array apparatus includes a patch antenna array provided on a unitary dielectric substrate, and a feed network provided on the same unitary substrate and proximity coupled to the patch antenna array. The reproducibility is enhanced by using photolithographic patterning and etching to produce both the patch antenna array and the feed network.

  10. Integrated Solar Array and Reflectarray Antenna for High Bandwidth Cubesats

    NASA Technical Reports Server (NTRS)

    Lewis, Dorothy; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Integrated Solar Array and Reflectarray Antenna (ISARA) mission will demonstrate a reflectarray antenna that increases downlink data rates for Cube- Sats from the existing baseline rate of 9.6 kilobits per second (kbps) to more than 100 megabits per second (Mbps). The ISARA spacecraft is slated for launch no earlier than Dec. 1, 2015.

  11. Evolutionary Design of a Phased Array Antenna Element

    NASA Technical Reports Server (NTRS)

    Globus, Al; Linden, Derek; Lohn, Jason

    2006-01-01

    We present an evolved S-band phased array antenna element design that meets the requirements of NASA's TDRS-C communications satellite scheduled for launch early next decade. The original specification called for two types of elements, one for receive only and one for transmit/receive. We were able to evolve a single element design that meets both specifications thereby simplifying the antenna and reducing testing and integration costs. The highest performance antenna found using a genetic algorithm and stochastic hill-climbing has been fabricated and tested. Laboratory results are largely consistent with simulation. Researchers have been investigating evolutionary antenna design and optimization since the early 1990s, and the field has grown in recent years its computer speed has increased and electromagnetic simulators have improved. Many antenna types have been investigated, including wire antennas, antenna arrays and quadrifilar helical antennas. In particular, our laboratory evolved a wire antenna design for NASA's Space Technology 5 (ST5) spacecraft. This antenna has been fabricated, tested, and is scheduled for launch on the three spacecraft in 2006.

  12. Linear antenna array optimization using flower pollination algorithm.

    PubMed

    Saxena, Prerna; Kothari, Ashwin

    2016-01-01

    Flower pollination algorithm (FPA) is a new nature-inspired evolutionary algorithm used to solve multi-objective optimization problems. The aim of this paper is to introduce FPA to the electromagnetics and antenna community for the optimization of linear antenna arrays. FPA is applied for the first time to linear array so as to obtain optimized antenna positions in order to achieve an array pattern with minimum side lobe level along with placement of deep nulls in desired directions. Various design examples are presented that illustrate the use of FPA for linear antenna array optimization, and subsequently the results are validated by benchmarking along with results obtained using other state-of-the-art, nature-inspired evolutionary algorithms such as particle swarm optimization, ant colony optimization and cat swarm optimization. The results suggest that in most cases, FPA outperforms the other evolutionary algorithms and at times it yields a similar performance. PMID:27066339

  13. Demonstration of a micromachined planar distribution network in gap waveguide technology for a linear slot array antenna at 100 GHz

    NASA Astrophysics Data System (ADS)

    Rahiminejad, S.; Zaman, A. U.; Haasl, S.; Kildal, P.-S.; Enoksson, P.

    2016-07-01

    The need for high frequency antennas is rapidly increasing with the development of new wireless rate communication technology. Planar antennas have an attractive form factor, but they require a distribution network. Microstrip technology is most commonly used at low frequency but suffers from large dielectric and ohmic losses at higher frequencies and particularly above 100 GHz. Substrate-integrated waveguides also suffer from dielectric losses. In addition, standard rectangular waveguide interfaces are inconvenient due to the four flange screws that must be tightly fastened to the antenna to avoid leakage. The current paper presents a planar slot array antenna that does not suffer from any of these problems. The distribution network is realized by micromachining using low-loss gap waveguide technology, and it can be connected to a standard rectangular waveguide flange without using any screws or additional packaging. To realize the antenna at these frequencies, it was fabricated with micromachining, which offers the required high precision, and a low-cost fabrication method. The antenna was micromachined with DRIE in two parts, one silicon-on-insulator plate and one Si plate, which were both covered with Au to achieve conductivity. The input reflection coefficient was measured to be below 10 dB over a 15.5% bandwidth, and the antenna gain was measured to be 10.4 dBi, both of which are in agreement with simulations.

  14. Microstrip patch antennas—basic properties and some recent advances

    NASA Astrophysics Data System (ADS)

    Kai-Fong, Lee

    1989-10-01

    For high-speed moving vehicles, it is desirable for the antenna to be "low profile". One of the early low profile antennas is the slot antenna, the theory of which was developed by Professor Henry G. Booker in a classic paper published in 1946. During the last decade and a half, a relatively new class of radiators known as microstrip patch antennas has received much attention. In addition to being low profile and conformable to a shaped surface, these antennas offer the potential advantages of light weight, low cost, ruggedness, and compatibility with integrated circuit technology. The main disadvantages are narrow bandwidth and the problems associated with copper loss and spurious radiation when the elements form an array. This paper begins with a description of the basic features of microstrip patch antennas, followed by a presentation of some of the research aimed at improving the frequency response and gain, particularly those to which the author and his collaborators have made contributions.

  15. MSAT mobile electronically steered phased array antenna development

    NASA Technical Reports Server (NTRS)

    Schmidt, Fred

    1988-01-01

    The Mobile Satellite Experiment (MSAT-X) breadboard antenna design demonstrates the feasibility of using a phased array in a mobile satellite application. An electronically steerable phased array capable of tracking geosynchronous satellites from anywhere in the Continental United States has been developed. The design is reviewed along with the test data. Cost analysis are presented which indicate that this design can be produced at a cost of $1620 per antenna.

  16. Compact antenna arrays with wide bandwidth and low sidelobe levels

    SciTech Connect

    Strassner, II, Bernd H.

    2014-09-09

    Highly efficient, low cost, easily manufactured SAR antenna arrays with lightweight low profiles, large instantaneous bandwidths and low SLL are disclosed. The array topology provides all necessary circuitry within the available antenna aperture space and between the layers of material that comprise the aperture. Bandwidths of 15.2 GHz to 18.2 GHz, with 30 dB SLLs azimuthally and elevationally, and radiation efficiencies above 40% may be achieved. Operation over much larger bandwidths is possible as well.

  17. Bandwidth enhancement of electromagnetic coupled nonuniform H-shaped microstrip patch antenna for higher band of Wi-MAX applications

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Dheeraj; Gulati, Gitansh; Saraswat, Srishti; Sharma, Komal

    2016-03-01

    The bandwidth enhancement of a stacked non-uniform electromagnetically coupled H-shaped Microstrip Antenna (SNHMA) with tapered edges is analyzed and simulated using the IE3D simulator. The proposed antenna prototype is drafted on FR-4 material and stacked further with an air discontinuity of 0.3 mm to the next layer. The various parameters optimized to achieve the best performance from the modified SNHMA primarily include a)length b)width of the patch c)air gap thickness. The redesigned antenna serves at two distinct frequencies with an elevated bandwidth of 30.85 % at the central frequency 5.762 GHz, approximately four times the bandwidth of the standard patch having the same dimensions. The simulated radiation patterns (E-plane and H-plane) are exhibited within the range of frequencies where the broadband response is observed. The specifications of the proposed structure make it promising for the higher band of Wi-MAX applications.

  18. Imaging antenna array at 119 microns. [for plasma diagnostics

    NASA Technical Reports Server (NTRS)

    Neikirk, N. P.; Tong, P. P.; Putledge, D. B.; Park, H.; Young, P. E.

    1982-01-01

    A focal-plane imaging antenna array has been demonstrated at 119 microns. The array is a line of evaporated silver bow-tie antennas with bismuth microbolometer detectors on a silicon substrate. Radiation is coupled into the array by a lens placed on the back of the substrate. The bolometers are thermally isolated from the silicon substrate with a half-micron layer of polyimide. The array performance is demonstrated by coherent imaging of a series of holes at half the diffraction-limited cut-off frequency.

  19. Antenna-coupled arrays of voltage-biased superconducting bolometers

    SciTech Connect

    Myers, Michael J.; Lee, Adrian T.; Richards, P.L.; Schwan, D.; Skidmore, J.T.; Smith, A.D.; Spieler, H.; Yoon, Jongsoo

    2001-07-23

    We report on the development of antenna-coupled Voltage-biased Superconducting Bolometers (VSBs) which use Transition-edge Sensors (TES). Antenna coupling can greatly simplify the fabrication of large multi-frequency bolometer arrays compared to horn-coupled techniques. This simplification can make it practical to implement 1000+ element arrays that fill the focal plane of mm/sub-mm wave telescopes. We have designed a prototype device with a double-slot dipole antenna, integrated band-defining filters, and a membrane-suspended bolometer. A test chip has been constructed and will be tested shortly.

  20. Technique for Radiometer and Antenna Array Calibration - TRAAC

    NASA Technical Reports Server (NTRS)

    Meyer, Paul; Sims, William; Varnavas, Kosta; McCracken, Jeff; Srinivasan, Karthik; Limaye, Ashutosh; Laymon, Charles; Richeson. James

    2012-01-01

    Highly sensitive receivers are used to detect minute amounts of emitted electromagnetic energy. Calibration of these receivers is vital to the accuracy of the measurements. Traditional calibration techniques depend on calibration reference internal to the receivers as reference for the calibration of the observed electromagnetic energy. Such methods can only calibrate errors in measurement introduced by the receiver only. The disadvantage of these existing methods is that they cannot account for errors introduced by devices, such as antennas, used for capturing electromagnetic radiation. This severely limits the types of antennas that can be used to make measurements with a high degree of accuracy. Complex antenna systems, such as electronically steerable antennas (also known as phased arrays), while offering potentially significant advantages, suffer from a lack of a reliable and accurate calibration technique. The proximity of antenna elements in an array results in interaction between the electromagnetic fields radiated (or received) by the individual elements. This phenomenon is called mutual coupling. The new calibration method uses a known noise source as a calibration load to determine the instantaneous characteristics of the antenna. The noise source is emitted from one element of the antenna array and received by all the other elements due to mutual coupling. This received noise is used as a calibration standard to monitor the stability of the antenna electronics.

  1. Terahertz line detection by a microlens array coupled photoconductive antenna array.

    PubMed

    Pradarutti, B; Müller, R; Freese, W; Matthäus, G; Riehemann, S; Notni, G; Nolte, S; Tünnermann, A

    2008-10-27

    We present THz ultrashort pulse detection by a photoconductive antenna array consisting of 16 photoconductive antennas. The efficient excitation of the photoconductive antennas has been realized by a microlens array which generates 16 single spots from the exciting fs-laser beam. This combination of optoelectronics and microoptics improves the detection efficiency by an order of magnitude in comparison to an excitation by a line focus. PMID:18958123

  2. Analysis of an infinite array of rectangular microstrip patches with idealized probe feeds

    NASA Technical Reports Server (NTRS)

    Pozar, D. M.; Schaubert, D. H.

    1984-01-01

    A solution is presented to the problem of an infinite array of microstrip patches fed by idealized current probes. The input reflection coefficient is calculated versus scan angle in an arbitrary scan plane, and the effects of substrate parameters and grid spacing are considered. It is pointed out that even when a Galerkin method is used the impedance matrix is not symmetric due to phasing through a unit cell, as required for scanning. The mechanism by which scan blindness can occur is discussed. Measurement results are presented for the reflection coefficient magnitude variation with angle for E-plane, H-plane, and D-plane scans, for various substrate parameters. Measured results from waveguide simulators are also presented, and the scan blindness phenomenon is observed and discussed in terms of forced surface waves and a modified grating lobe diagram.

  3. Array trade-off study using multilayer parasitic subarrays

    NASA Technical Reports Server (NTRS)

    Zaman, A.; Lee, R. Q.; Acosta, R. J.

    1988-01-01

    The use of multilayer parasitic patch arrays in a microstrip phased array offers many potential advantages. An analytical study of microstrip arrays with high gain multilayer parasitic patch subarrays and conventional patch antennas is presented. It is indicated that a thinned array of half as many multilayer parasitic patch subarrays (per row and column) at twice the spacing will perform as well as the full array of ordinary patch antennas. The criterion for comparison was array gain, 3 dB beamwidth and sidelobe level. The attendant reduction in the required number of patch antennas and consequently, MMIC phase shifters is very significant in terms of array complexity, cost and power loss.

  4. THz radiation properties of silver V-cone antenna arrays

    NASA Astrophysics Data System (ADS)

    Qian, Jun; Huang, Mengya; Hu, Mingzhe

    2012-12-01

    In the present article, silver cone antenna and its arrays are designed according to the requirement of wide bandwidth terahertz irradiation property. Coordinate transformation method is employed to analyze the solution process of the integrate equation of the irradiated electromagnetic field. And CST microwave studio software is employed to simulate the terahertz irradiation properties of Ag cone antenna arrays. Theoretical analysis and simulation results both manifest that the single Ag cone antenna with micrometer scale size can irradiate a wide bandwidth THz wave with the gain of 22.7dBi, while its corresponding antenna arrays with proper configuration can further improve the radiation pattern and enhance the gain to 42.5dBi. The theoretical analysis and CST simulation results will be useful for the guidance of experimental investigation of terahertz irradiation sources.

  5. Antenna array geometry optimization for a passive coherent localisation system

    NASA Astrophysics Data System (ADS)

    Knott, Peter; Kuschel, Heiner; O'Hagan, Daniel

    2012-11-01

    Passive Coherent Localisation (PCL), also known as Passive Radar, making use of RF sources of opportunity such as Radio or TV Broadcasting Stations, Cellular Phone Network Base Stations, etc. is an advancing technology for covert operation because no active radar transmitter is required. It is also an attractive addition to existing active radar stations because it has the potential to discover low-flying and low-observable targets. The CORA (Covert Radar) experimental passive radar system currently developed at Fraunhofer-FHR features a multi-channel digital radar receiver and a circular antenna array with separate elements for the VHF- and the UHF-range and is used to exploit alternatively Digital Audio (DAB) or Video Broadcasting (DVB-T) signals. For an extension of the system, a wideband antenna array is being designed for which a new discone antenna element has been developed covering the full DVB-T frequency range. The present paper describes the outline of the system and the numerical modelling and optimisation methods applied to solve the complex task of antenna array design: Electromagnetic full wave analysis is required for the parametric design of the antenna elements while combinatorial optimization methods are applied to find the best array positions and excitation coefficients for a regular omni-directional antenna performance. The different steps are combined in an iterative loop until the optimum array layout is found. Simulation and experimental results for the current system will be shown.

  6. Large-Aperture Membrane Active Phased-Array Antennas

    NASA Technical Reports Server (NTRS)

    Karasik, Boris; McGrath, William; Leduc, Henry

    2009-01-01

    Large-aperture phased-array microwave antennas supported by membranes are being developed for use in spaceborne interferometric synthetic aperture radar systems. There may also be terrestrial uses for such antennas supported on stationary membranes, large balloons, and blimps. These antennas are expected to have areal mass densities of about 2 kg/sq m, satisfying a need for lightweight alternatives to conventional rigid phased-array antennas, which have typical areal mass densities between 8 and 15 kg/sq m. The differences in areal mass densities translate to substantial differences in total mass in contemplated applications involving aperture areas as large as 400 sq m. A membrane phased-array antenna includes patch antenna elements in a repeating pattern. All previously reported membrane antennas were passive antennas; this is the first active membrane antenna that includes transmitting/receiving (T/R) electronic circuits as integral parts. Other integral parts of the antenna include a network of radio-frequency (RF) feed lines (more specifically, a corporate feed network) and of bias and control lines, all in the form of flexible copper strip conductors on flexible polymeric membranes. Each unit cell of a prototype antenna (see Figure 1) contains a patch antenna element and a compact T/R module that is compatible with flexible membrane circuitry. There are two membrane layers separated by a 12.7-mm air gap. Each membrane layer is made from a commercially available flexible circuit material that, as supplied, comprises a 127-micron-thick polyimide dielectric layer clad on both sides with 17.5-micron-thick copper layers. The copper layers are patterned into RF, bias, and control conductors. The T/R module is located on the back side of the ground plane and is RF-coupled to the patch element via a slot. The T/R module is a hybrid multilayer module assembled and packaged independently and attached to the membrane array. At the time of reporting the information for

  7. Analysis of characteristics of plane microwave antennas with a linearly expanding aperture for disk antenna arrays

    NASA Astrophysics Data System (ADS)

    Zayarnyi, V. P.; Parpula, A. A.; Girich, V. S.

    2014-11-01

    Mathematical models constructed for plane symmetric microwave antennas with a linearly expanding aperture make it possible to calculate the directional patterns depending on the aperture configuration. The directional patterns for analogous antennas operating in the range 5.9-12.5 GHz are measured experimentally; good agreement between the theoretical and experimental results is observed. The regularities in the influence of the aperture configuration of the antennas under investigation on the shape of the principal lobe of their directional patterns are established; these regularities are used for designing disk antenna arrays of circular and sector scan on their basis.

  8. Resonant frequencies of irregularly shaped microstrip antennas using method of moments

    NASA Technical Reports Server (NTRS)

    Deshpande, Manohar D.; Shively, David G.; Cockrell, C. R.

    1993-01-01

    This paper describes an application of the method of moments to determine resonant frequencies of irregularly shaped microstrip patches embedded in a grounded dielectric slab. For analysis, the microstrip patch is assumed to be excited by a linearly polarized plane wave that is normal to the patch. The surface-current density that is induced on the patch because of the incident field is expressed in terms of subdomain functions by dividing the patch into identical rectangular subdomains. The amplitudes of the subdomain functions, as a function of frequency, are determined using the electric-field integral equation (EFIE) approach in conjunction with the method of moments. The resonant frequencies of the patch are then obtained by selecting the frequency at which the amplitude of the surface-current density is real. The resonant frequencies of the equilateral triangular and other nonrectangular patches are computed using the present technique, and these frequencies are compared with measurements and other independent calculations.

  9. Technique for Extension of Small Antenna Array Mutual-Coupling Data to Larger Antenna Arrays

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.

    1996-01-01

    A technique is presented whereby the mutual interaction between a small number of elements in a planar array can be interpolated and extrapolated to accurately predict the combined interactions in a much larger array of many elements. An approximate series expression is developed, based upon knowledge of the analytical characteristic behavior of the mutual admittance between small aperture antenna elements in a conducting ground plane. This expression is utilized to analytically extend known values for a few spacings and orientations to other element configurations, thus eliminating the need to numerically integrate a large number of highly oscillating and slowly converging functions. This paper shows that the technique can predict very accurately the mutual coupling between elements in a very large planar array with a knowledge of the self-admittance of an isolated element and the coupling between only two-elements arranged in eight different pair combinations. These eight pair combinations do not necessarily have to correspond to pairs in the large array, although all of the individual elements must be identical.

  10. Use of microstrip patch antennas in grain and pulverized materials permittivity measurement

    USGS Publications Warehouse

    El Sabbagh, M.A.; Ramahi, O.M.; Trabelsi, S.; Nelson, S.O.; Khan, L.

    2003-01-01

    A free-space microwave system developed for the measurement of the relative complex permittivity of granular materials and of pulverized materials was reported. The system consists of a transmitting antenna and a receiving antenna separated by a space filled by the sample to be characterized and a network analyzer for transmission measurement. The receiving antenna was mounted on a movable plate, which gives the flexibility of having different sample thicknesses.

  11. Phased array-fed antenna configuration study: Technology assessment

    NASA Technical Reports Server (NTRS)

    Croswell, W. F.; Ball, D. E.; Taylor, R. C.

    1983-01-01

    Spacecraft array fed reflector antenna systems were assessed for particular application to a multiple fixed spot beam/multiple scanning spot beam system. Reflector optics systems are reviewed in addition to an investigation of the feasibility of the use of monolithic microwave integrated circuit power amplifiers and phase shifters in each element of the array feed.

  12. Antennas for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

    A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

  13. Flexible 16 Antenna Array for Microwave Breast Cancer Detection.

    PubMed

    Bahramiabarghouei, Hadi; Porter, Emily; Santorelli, Adam; Gosselin, Benoit; Popović, Milica; Rusch, Leslie A

    2015-10-01

    Radar-based microwave imaging has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues has been studied over a wide frequency band for this application. We design single- and dual-polarization antennas for wireless ultrawideband breast cancer detection systems using an inhomogeneous multilayer model of the human breast. Antennas made from flexible materials are more easily adapted to wearable applications. Miniaturized flexible monopole and spiral antennas on a 50-μm Kapton polyimide are designed, using a high-frequency structure simulator, to be in contact with biological breast tissues. The proposed antennas are designed to operate in a frequency range of 2-4 GHz (with reflection coefficient (S11) below -10 dB). Measurements show that the flexible antennas have good impedance matching when in different positions with different curvature around the breast. Our miniaturized flexible antennas are 20 mm × 20 mm. Furthermore, two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system. By using a reflector for the arrays, the penetration of the propagated electromagnetic waves from the antennas into the breast can be improved by factors of 3.3 and 2.6, respectively. PMID:26011862

  14. Modern Design of Resonant Edge-Slot Array Antennas

    NASA Technical Reports Server (NTRS)

    Gosselin, R. B.

    2006-01-01

    Resonant edge-slot (slotted-waveguide) array antennas can now be designed very accurately following a modern computational approach like that followed for some other microwave components. This modern approach makes it possible to design superior antennas at lower cost than was previously possible. Heretofore, the physical and engineering knowledge of resonant edge-slot array antennas had remained immature since they were introduced during World War II. This is because despite their mechanical simplicity, high reliability, and potential for operation with high efficiency, the electromagnetic behavior of resonant edge-slot antennas is very complex. Because engineering design formulas and curves for such antennas are not available in the open literature, designers have been forced to implement iterative processes of fabricating and testing multiple prototypes to derive design databases, each unique for a specific combination of operating frequency and set of waveguide tube dimensions. The expensive, time-consuming nature of these processes has inhibited the use of resonant edge-slot antennas. The present modern approach reduces costs by making it unnecessary to build and test multiple prototypes. As an additional benefit, this approach affords a capability to design an array of slots having different dimensions to taper the antenna illumination to reduce the amplitudes of unwanted side lobes. The heart of the modern approach is the use of the latest commercially available microwave-design software, which implements finite-element models of electromagnetic fields in and around waveguides, antenna elements, and similar components. Instead of building and testing prototypes, one builds a database and constructs design curves from the results of computational simulations for sets of design parameters. The figure shows a resonant edge-slot antenna designed following this approach. Intended for use as part of a radiometer operating at a frequency of 10.7 GHz, this antenna

  15. Novel magneto-electro-dielectric waveguided metamaterials and its applications to microstrip patch antennas

    NASA Astrophysics Data System (ADS)

    Cai, Tong; Wang, Guang-Ming; Liang, Jian-Gang; Song, Zhi-Jie

    2014-09-01

    A novel magneto-electro-dielectric waveguided metamaterial (MED-WG-MTM) is proposed consisting of electric complementary spiral ring resonators and magnetic embedded Wunderlich line. Based on the control of effective medium parameters, the working mechanism of miniaturization, wide bandwidth, and also dual-band approach by loading MED-WG-MTM cells are investigated in depth. For experimental demonstration, two types of antennas are designed, fabricated, and measured following the established design procedures. For the former, the antenna with MED-WG-MTM loading realizes a miniaturization of 42.53 % and also 10 dB impedance bandwidth of about 3.71 times compared with the conventional antenna. In the latter case, dual-band antenna is researched. The prototype features compact occupying an area of only 0.20λ 0 × 0.20λ 0 and shows desirable similar radiation patterns. Moreover, both antennas are free of metallic via holes and practical for wireless communication system.

  16. Novel magneto-electro-dielectric waveguided metamaterials and its applications to microstrip patch antennas

    NASA Astrophysics Data System (ADS)

    Cai, Tong; Wang, Guang-Ming; Liang, Jian-Gang; Song, Zhi-Jie

    2015-01-01

    A novel magneto-electro-dielectric waveguided metamaterial (MED-WG-MTM) is proposed consisting of electric complementary spiral ring resonators and magnetic embedded Wunderlich line. Based on the control of effective medium parameters, the working mechanism of miniaturization, wide bandwidth, and also dual-band approach by loading MED-WG-MTM cells are investigated in depth. For experimental demonstration, two types of antennas are designed, fabricated, and measured following the established design procedures. For the former, the antenna with MED-WG-MTM loading realizes a miniaturization of 42.53 % and also 10 dB impedance bandwidth of about 3.71 times compared with the conventional antenna. In the latter case, dual-band antenna is researched. The prototype features compact occupying an area of only 0.20 λ 0 × 0.20 λ 0 and shows desirable similar radiation patterns. Moreover, both antennas are free of metallic via holes and practical for wireless communication system.

  17. Phased array antenna investigation for CubeSat size satellites

    NASA Astrophysics Data System (ADS)

    Dang, Kien

    Increasing bandwidth of the communication link has been a challenge for CubeSat class satellite. Traditional satellites usually utilizes high gain antennas for this purpose, but these antenna are rarely seen in CubeSat because of its power, volume and weight constraints. To solve these issues, this dissertation presents a phased array antenna system prototyped at 2.45 GHz with 17.7 dBi gain at broadside, 14.2 dBi at +/-40°, 50 MHz bandwidth, and fits on a side of a 3U CubeSat. The gain can be increased by adding more antenna elements into the array as needed. Testing for electronic beam steering has been completed and detailed results will be presented.

  18. Slotted waveguide array antennas for spaceborne SAR applications

    NASA Astrophysics Data System (ADS)

    Bostrom, D. E.; Carnegis, G. A.; Golvin, B.; Knoell, A. C.

    1983-07-01

    Starting with mission definitions and constraints for the NASA proposed Shuttle Active Microwave Experiments (SAMEX) and Free Flying Imaging Radar Experiment (FIREX), Hughes Aircraft Company has compiled and studied the technology available for slotted waveguide planar array antennas suitable for spaceborne SAR application. Antenna performance is derived, and fabrication techniques are discussed. Mission requirements will always lead to an aperture subdivided into waveguide modules, thereby validating a module definition for other mission building blocks. Finally, a specific design is proposed for a SAMEX mission using the modules as RF aperture building blocks, resulting in a (nominal) 15.1 meter by 5.5 meter extensile dual polarized L-, C-, and X-band planar array with an associated extensile graphite/epoxy support structure. Antenna development begin with a fabrication method development study involving a representative portion of an antenna module.

  19. Slotted waveguide array antennas for spaceborne SAR applications

    NASA Technical Reports Server (NTRS)

    Bostrom, D. E.; Carnegis, G. A.; Golvin, B.; Knoell, A. C.

    1983-01-01

    Starting with mission definitions and constraints for the NASA proposed Shuttle Active Microwave Experiments (SAMEX) and Free Flying Imaging Radar Experiment (FIREX), Hughes Aircraft Company has compiled and studied the technology available for slotted waveguide planar array antennas suitable for spaceborne SAR application. Antenna performance is derived, and fabrication techniques are discussed. Mission requirements will always lead to an aperture subdivided into waveguide modules, thereby validating a module definition for other mission building blocks. Finally, a specific design is proposed for a SAMEX mission using the modules as RF aperture building blocks, resulting in a (nominal) 15.1 meter by 5.5 meter extensile dual polarized L-, C-, and X-band planar array with an associated extensile graphite/epoxy support structure. Antenna development begin with a fabrication method development study involving a representative portion of an antenna module.

  20. Applications of trimode waveguide feeds in adaptive virtual array antennas

    NASA Astrophysics Data System (ADS)

    Allahgholi Pour, Z.; Shafai, Lotfollah

    2015-03-01

    This paper presents the formation of an adaptive virtual array antenna in a symmetric parabolic reflector antenna illuminated by trimode circular waveguide feeds with different mode alignments. The modes of interest are the TE11, TE21, and TM01 type modes. The terms TE and TM stand for the transverse electric and transverse magnetic modes, respectively. By appropriately exciting these modes and varying the mode orientations inside the primary feed, the effective source of radiation is displaced on the reflector aperture, while the resulting secondary patterns remain axial. Different antenna parameters such as gain, cross polarization, and phase center locations are investigated. It is demonstrated that the extra third mode facilitates the formation of symmetric virtual array antennas with reasonable cross polarization discriminations at the diagonal plane.

  1. Modulation transfer function of antenna-coupled infrared detector arrays.

    PubMed

    Boreman, G D; Dogariu, A; Christodoulou, C; Kotter, D

    1996-11-01

    Individual antenna-coupled IR bolometers have recently been demonstrated at wavelengths near 10 μm. If focal-plane arrays (FPA's) of antenna-coupled detectors can be fabricated, enhancement of IR-imager performance is possible. A first step in the design process is to analyze the image-quality potential of antenna-coupled, FPA-based imagers in terms of the modulation transfer function (MTF). The key step in our analysis is development of a cross-talk MTF that accounts for the electromagnetic coupling between adjacent antennas in the FPA. We find that electromagnetic cross talk will not be a significant image-quality factor in antenna-coupled IR FPA's. PMID:21127627

  2. Modulation transfer function of antenna-coupled infrared detector arrays

    NASA Astrophysics Data System (ADS)

    Boreman, Glenn D.; Dogariu, Aristide; Christodoulou, Christos; Kotter, Dale

    1996-11-01

    Individual antenna-coupled IR bolometers have recently been demonstrated at wavelengths near 10 mu m. If focal-plane arrays (FPA's) of antenna-coupled detectors can be fabricated, enhancement of IR-imager performance is possible. A first step in the design process is to analyze the image-quality potential of antenna-coupled, FPA-based imagers in terms of the modulation transfer function (MTF). The key step in our analysis is development of a cross-talk MTF that accounts for the electromagnetic coupling between adjacent antennas in the FPA. We find that electromagnetic cross talk will not be a significant image-quality factor in antenna-coupled IR FPA's.

  3. Accurate Insertion Loss Measurements of the Juno Patch Array Antennas

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil; Chen, Jacqueline; Hodges, Richard; Demas, John

    2010-01-01

    This paper describes two independent methods for estimating the insertion loss of patch array antennas that were developed for the Juno Microwave Radiometer instrument. One method is based principally on pattern measurements while the other method is based solely on network analyzer measurements. The methods are accurate to within 0.1 dB for the measured antennas and show good agreement (to within 0.1dB) of separate radiometric measurements.

  4. Algorithmic sensor failure detection on passive antenna arrays

    NASA Astrophysics Data System (ADS)

    Chun, Joohwan; Luk, Franklin T.

    1991-12-01

    We present an algorithm that can detect and isolate a single passive antenna failure under the assumption of slowly time varying signal sources. Our failure detection algorithm recursively computes an eigenvalue decomposition of the covariance of the "syndrome" vector. The sensor failure is detected using the largest eigenvalue, and the faulty sensor is located using the corresponding eigenvector. The algorithm can also be used in conjunction with existing singular value decomposition or orthogonal triangularization based recursive antenna array processing methods.

  5. Quadrature transmit array design using single-feed circularly polarized patch antenna for parallel transmission in MR imaging.

    PubMed

    Pang, Yong; Yu, Baiying; Vigneron, Daniel B; Zhang, Xiaoliang

    2014-02-01

    Quadrature coils are often desired in MR applications because they can improve MR sensitivity and also reduce excitation power. In this work, we propose, for the first time, a quadrature array design strategy for parallel transmission at 298 MHz using single-feed circularly polarized (CP) patch antenna technique. Each array element is a nearly square ring microstrip antenna and is fed at a point on the diagonal of the antenna to generate quadrature magnetic fields. Compared with conventional quadrature coils, the single-feed structure is much simple and compact, making the quadrature coil array design practical. Numerical simulations demonstrate that the decoupling between elements is better than -35 dB for all the elements and the RF fields are homogeneous with deep penetration and quadrature behavior in the area of interest. Bloch equation simulation is also performed to simulate the excitation procedure by using an 8-element quadrature planar patch array to demonstrate its feasibility in parallel transmission at the ultrahigh field of 7 Tesla. PMID:24649430

  6. Quadrature transmit array design using single-feed circularly polarized patch antenna for parallel transmission in MR imaging

    PubMed Central

    Pang, Yong; Yu, Baiying; Vigneron, Daniel B.

    2014-01-01

    Quadrature coils are often desired in MR applications because they can improve MR sensitivity and also reduce excitation power. In this work, we propose, for the first time, a quadrature array design strategy for parallel transmission at 298 MHz using single-feed circularly polarized (CP) patch antenna technique. Each array element is a nearly square ring microstrip antenna and is fed at a point on the diagonal of the antenna to generate quadrature magnetic fields. Compared with conventional quadrature coils, the single-feed structure is much simple and compact, making the quadrature coil array design practical. Numerical simulations demonstrate that the decoupling between elements is better than –35 dB for all the elements and the RF fields are homogeneous with deep penetration and quadrature behavior in the area of interest. Bloch equation simulation is also performed to simulate the excitation procedure by using an 8-element quadrature planar patch array to demonstrate its feasibility in parallel transmission at the ultrahigh field of 7 Tesla. PMID:24649430

  7. A 20 GHz circularly polarized, fan beam slot array antenna

    NASA Astrophysics Data System (ADS)

    Weikle, D. C.

    1982-03-01

    An EHF waveguide slot array was developed for possible use as a receive-only paging antenna for ground mobile terminals. The design, fabrication, and measured performance of this antenna are presented. The antenna generates a circularly polarized fan beam that is narrow in azimuth and broad in elevation. When mechanically rotated in azimuth, it can receive a 20 GHz satellite transmission independent of mobile terminal direction. Azimuth plane sidelobe levels, which are typically <-40 dB from the main lobe, provide for discrimination against ground and airborne jammers.

  8. Multi-carrier mobile TDMA system with active array antenna

    NASA Technical Reports Server (NTRS)

    Suzuki, Ryutaro; Matsumoto, Yasushi; Hamamoto, Naokazu

    1990-01-01

    A multi-carrier time division multiple access (TDMA) is proposed for the future mobile satellite communications systems that include a multi-satellite system. This TDMA system employs the active array antenna in which the digital beam forming technique is adopted to control the antenna beam direction. The antenna beam forming is carried out at the base band frequency by using the digital signal processing technique. The time division duplex technique is applied for the TDM/TDMA burst format, in order not to overlap transmit and receive timing.

  9. MIMO communications within the HF band using compact antenna arrays

    NASA Astrophysics Data System (ADS)

    Gunashekar, S. D.; Warrington, E. M.; Feeney, S. M.; Salous, S.; Abbasi, N. M.

    2010-12-01

    Measurements have been made over a 255 km radio path between Durham and Leicester in the UK in order to investigate the potential applicability of multiple input multiple output (MIMO) techniques to communications within the HF band. This paper describes the results from experiments in which compact heterogeneous antenna arrays have been employed. The results of these experiments indicate that traditional spaced HF antenna arrays can be replaced by compact, active, heterogeneous arrays in order to achieve the required levels of decorrelation between the various antenna elements. An example case study is also presented which highlights the importance of the variable nature of the ionosphere in the context of HF-MIMO radio links.

  10. Strong near field enhancement in THz nano-antenna arrays

    PubMed Central

    Feuillet-Palma, Cheryl; Todorov, Yanko; Vasanelli, Angela; Sirtori, Carlo

    2013-01-01

    A key issue in modern photonics is the ability to concentrate light into very small volumes, thus enhancing its interaction with quantum objects of sizes much smaller than the wavelength. In the microwave domain, for many years this task has been successfully performed by antennas, built from metals that can be considered almost perfect at these frequencies. Antenna-like concepts have been recently extended into the THz and up to the visible, however metal losses increase and limit their performances. In this work we experimentally study the light coupling properties of dense arrays of subwavelength THz antenna microcavities. We demonstrate that the combination of array layout with subwavelength electromagnetic confinement allows for 104-fold enhancement of the electromagnetic energy density inside the cavities, despite the low quality factor of a single element. This effect is quantitatively described by an analytical model that can be applied for the optimization of any nanoantenna array. PMID:23449101

  11. Strong near field enhancement in THz nano-antenna arrays.

    PubMed

    Feuillet-Palma, Cheryl; Todorov, Yanko; Vasanelli, Angela; Sirtori, Carlo

    2013-01-01

    A key issue in modern photonics is the ability to concentrate light into very small volumes, thus enhancing its interaction with quantum objects of sizes much smaller than the wavelength. In the microwave domain, for many years this task has been successfully performed by antennas, built from metals that can be considered almost perfect at these frequencies. Antenna-like concepts have been recently extended into the THz and up to the visible, however metal losses increase and limit their performances. In this work we experimentally study the light coupling properties of dense arrays of subwavelength THz antenna microcavities. We demonstrate that the combination of array layout with subwavelength electromagnetic confinement allows for 10(4)-fold enhancement of the electromagnetic energy density inside the cavities, despite the low quality factor of a single element. This effect is quantitatively described by an analytical model that can be applied for the optimization of any nanoantenna array. PMID:23449101

  12. Directional field enhancement of dielectric nano optical disc antenna arrays

    NASA Astrophysics Data System (ADS)

    Wang, Ivan; Du, Y.

    2011-11-01

    This paper presents a discussion on the directive field enhancement of dielectric disc antenna arrays in optical band. The property of dielectric material is addressed, and field modes in a cylindrical resonator are discussed. It is identified that the fundamental mode of HE 11δ generates the far field with a higher directivity than other modes. More effective field enhancement in the radiation direction could be achieved by using multiple-disc antenna arrays. Simulation examples indicate that the directivity of a disc antenna array varies with the disc spacing. The maximum directivity is observed when the disc spacing is approximately equal to the half of the vacuum wavelength. The maximum directivity can be improved significantly when the disc number is increased.

  13. Hydrostar Thermal and Structural Deformation Analyses of Antenna Array Concept

    NASA Technical Reports Server (NTRS)

    Amundsen, Ruth M.; Hope, Drew J.

    1998-01-01

    The proposed Hydrostar mission used a large orbiting antenna array to demonstrate synthetic aperture technology in space while obtaining global soil moisture data. In order to produce accurate data, the array was required to remain as close as possible to its perfectly aligned placement while undergoing the mechanical and thermal stresses induced by orbital changes. Thermal and structural analyses for a design concept of this antenna array were performed. The thermal analysis included orbital radiation calculations, as well as parametric studies of orbit altitude, material properties and coating types. The thermal results included predicted thermal distributions over the array for several cases. The structural analysis provided thermally-driven deflections based on these cases, as well as based on a 1-g inertial load. In order to minimize the deflections of the array in orbit, the use of XN70, a carbon-reinforced polycyanate composite, was recommended.

  14. Optical beam forming techniques for phased array antennas

    NASA Technical Reports Server (NTRS)

    Wu, Te-Kao; Chandler, C.

    1993-01-01

    Conventional phased array antennas using waveguide or coax for signal distribution are impractical for large scale implementation on satellites or spacecraft because they exhibit prohibitively large system size, heavy weight, high attenuation loss, limited bandwidth, sensitivity to electromagnetic interference (EMI) temperature drifts and phase instability. However, optical beam forming systems are smaller, lighter, and more flexible. Three optical beam forming techniques are identified as applicable to large spaceborne phased array antennas. They are (1) the optical fiber replacement of conventional RF phased array distribution and control components, (2) spatial beam forming, and (3) optical beam splitting with integrated quasi-optical components. The optical fiber replacement and the spatial beam forming approaches were pursued by many organizations. Two new optical beam forming architectures are presented. Both architectures involve monolithic integration of the antenna radiating elements with quasi-optical grid detector arrays. The advantages of the grid detector array in the optical process are the higher power handling capability and the dynamic range. One architecture involves a modified version of the original spatial beam forming approach. The basic difference is the spatial light modulator (SLM) device for controlling the aperture field distribution. The original liquid crystal light valve SLM is replaced by an optical shuffling SLM, which was demonstrated for the 'smart pixel' technology. The advantages are the capability of generating the agile beams of a phased array antenna and to provide simultaneous transmit and receive functions. The second architecture considered is the optical beam splitting approach. This architecture involves an alternative amplitude control for each antenna element with an optical beam power divider comprised of mirrors and beam splitters. It also implements the quasi-optical grid phase shifter for phase control and grid

  15. Multifrequency synthetic aperture radar antenna comparison study. [for remote sensing

    NASA Technical Reports Server (NTRS)

    Blevins, B. A.

    1983-01-01

    Three multifrequency, dual polarization SAR antenna designs are reviewed. The SAR antenna design specifications were for a "straw man' SAR which would approximate the requirements for projected shuttle-based SAR's. Therefore, the physical dimensions were constrained to be compatible with the space shuttle. The electrical specifications were similar to those of SIR-A and SIR-B with the addition of dual polarization and the addition of C and X band operation. Early in the antenna design considerations, three candidate technologies emerged as having promise. They were: (1) microstrip patch planar array antennas, (2) slotted waveguide planar array antennas, and (3) open-ended waveguide planar array antennas.

  16. Optimization of an antenna array using genetic algorithms

    SciTech Connect

    Kiehbadroudinezhad, Shahideh; Noordin, Nor Kamariah; Sali, A.; Abidin, Zamri Zainal

    2014-06-01

    An array of antennas is usually used in long distance communication. The observation of celestial objects necessitates a large array of antennas, such as the Giant Metrewave Radio Telescope (GMRT). Optimizing this kind of array is very important when observing a high performance system. The genetic algorithm (GA) is an optimization solution for these kinds of problems that reconfigures the position of antennas to increase the u-v coverage plane or decrease the sidelobe levels (SLLs). This paper presents how to optimize a correlator antenna array using the GA. A brief explanation about the GA and operators used in this paper (mutation and crossover) is provided. Then, the results of optimization are discussed. The results show that the GA provides efficient and optimum solutions among a pool of candidate solutions in order to achieve the desired array performance for the purposes of radio astronomy. The proposed algorithm is able to distribute the u-v plane more efficiently than GMRT with a more than 95% distribution ratio at snapshot, and to fill the u-v plane from a 20% to more than 68% filling ratio as the number of generations increases in the hour tracking observations. Finally, the algorithm is able to reduce the SLL to –21.75 dB.

  17. Suspended-Patch Antenna With Inverted, EM-Coupled Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    An improved suspended-patch antenna has been designed to operate at a frequency of about 23 GHz with linear polarization and to be one of four identical antennas in a rectangular array. The antenna includes a parasitic patch on top of a suspended dielectric superstrate, an active patch on top of a suspended dielectric substrate, a microstrip on the bottom of the dielectric substrate, and a ground plane. The microstrip, the ground plane, the airgap between them, and the dielectric substrate together constitute a transmission line that has an impedance of 50 Ohm and is electromagnetically (EM) coupled to the active patch. The parasitic patch is, in turn, excited by the active patch. The microstrip feed is characterized as inverted because the microstrip is on the bottom of the substrate, whereas microstrips are usually placed on the tops of dielectric substrates

  18. Microwave power transmitting phased array antenna research project

    NASA Technical Reports Server (NTRS)

    Dickinson, R. M.

    1978-01-01

    An initial design study and the development results of an S band RF power transmitting phased array antenna experiment system are presented. The array was to be designed, constructed and instrumented to permit wireless power transmission technology evaluation measurements. The planned measurements were to provide data relative to the achievable performance in the state of the art of flexible surface, retrodirective arrays, as a step in technically evaluating the satellite power system concept for importing to earth, via microwave beams, the nearly continuous solar power available in geosynchronous orbit. Details of the microwave power transmitting phased array design, instrumentation approaches, system block diagrams, and measured component and breadboard characteristics achieved are presented.

  19. Antenna of adjustable bandwidth based on a pentagonal array

    NASA Astrophysics Data System (ADS)

    Tecpoyotl-Torres, M.; Vera-Dimas, J. G.; Cabello Ruiz, R.; García-García, O.; Escobedo-Alatorre, J.; Sanchez-Mondragon, J.; Torres-Cisneros, M.; Varona, J.; Vargas-Bernal, R.

    2011-09-01

    Antenna characteristics are chosen according to the features determined by the systems where they will be used. While some systems require a very narrow bandwidth, others may operate with a much wider bandwidth. Some techniques used for increasing the bandwidth of a given antenna have considered mechanical adjustment of the air layer thickness, with the consequent change on the effective permittivity and performance. Some other systems consider a suitable choice of feeding techniques and impedance matching network. However, approaches for reducing the bandwidth have not received the same level of attention. Narrow bandwidth antennas are of particular interest in security and surveillance systems. In this work we present a technique, based on the design of a pentagonal antenna array, which allows for adjusting the bandwidth in either direction. The array is formed by an inner patch designed at the desired operating frequency of the system and a gap coupled external ring centered at a different frequency (lower or very near the operating frequency), which determines the potential bandwidth increment or decrement. The feed point is located on the inner patch. As a proof-of-concept, this work offers a tuning range that goes from -40% of the center frequency up to +50% of the center operating frequency of the patch antenna. The single patch antenna of this work was designed and simulated at an operating frequency of 4.9 GHz on RT/Duroid 5880.

  20. View to the eastnortheast of the Antenna Array OvertheHorizon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the east-northeast of the Antenna Array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Six Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  1. General view looking northnortheast at antenna array OvertheHorizon Backscatter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view looking north-northeast at antenna array - Over-the-Horizon Backscatter Radar Network, Moscow Radar Site Transmit Sector Two Antenna Array, At the end of Steam Road, Moscow, Somerset County, ME

  2. Detail of antenna array, looking northnorthwest OvertheHorizon Backscatter Radar ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of antenna array, looking north-northwest - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Five Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

  3. View to the east of the Antenna Array OvertheHorizon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the east of the Antenna Array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Six Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  4. General view of Antenna Array, looking west OvertheHorizon Backscatter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of Antenna Array, looking west - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Six Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

  5. View to the northeast of the antenna array OvertheHorizon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View to the northeast of the antenna array - Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Four Antenna Array, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

  6. General view looking northnortheast at antenna array OvertheHorizon Backscatter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view looking north-northeast at antenna array - Over-the-Horizon Backscatter Radar Network, Moscow Radar Site Transmit Sector One Antenna Array, At the end of Steam Road, Moscow, Somerset County, ME

  7. Phased array antenna analysis using hybrid finite element methods

    NASA Astrophysics Data System (ADS)

    McGrath, Daniel T.

    1993-06-01

    This research in computational electromagnetics developed a new method for predicting the near-field mutual coupling effects in phased array antennas, using the finite element method (FEM) in combination with integral equations. Accurate feed modeling is accomplished by enforcing continuity between the FEM solution and an arbitrary number of wave guide models across a ground plane aperture. A periodic integral equation is imposed above the antenna's physical structure in order to enforce the radiation condition and to confine the analysis to an array unit cell. The electric field is expanded in terms of vector finite elements, and Galerkin's method is used to write the problem as a matrix equation. A general-purpose computer code was developed and validated by comparing its results to published data for several array types. Its versatility was demonstrated with predictions of the scanning properties of arrays of printed dipoles and printed flared notches.

  8. Flexible sixteen monopole antenna array for microwave breast cancer detection.

    PubMed

    Bahrami, H; Porter, E; Santorelli, A; Gosselin, B; Popovic, M; Rusch, L A

    2014-01-01

    Radar based microwave imaging (MI) has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues over a wide frequency band has been made possible by ultra-wideband (UWB) techniques. In this paper, a flexible, compact monopole antenna on a 100 μm Kapton polyimide is designed, using a high frequency structure simulator (HFSS), to be in contact with biological breast tissues over the 2-5GHz frequency range. The antenna parameters are optimized to obtain a good impedance match over the required frequency range. The designed antenna size is 18mm × 18mm. Further, a flexible conformal 4×4 ultra-wideband antenna array, in a format similar to that of a bra, was developed for a radar-based breast cancer detection system. PMID:25570813

  9. An adaptive array antenna for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Milne, Robert

    1988-01-01

    The adaptive array is linearly polarized and consists essentially of a driven lambda/4 monopole surrounded by an array of parasitic elements all mounted on a ground plane of finite size. The parasitic elements are all connected to ground via pin diodes. By applying suitable bias voltages, the desired parasitic elements can be activated and made highly reflective. The directivity and pointing of the antenna beam can be controlled in both the azimuth and elevation planes using high speed digital switching techniques. The antenna RF losses are neglible and the maximum gain is close to the theoretical value determined by the effective aperture size. The antenna is compact, has a low profile, is inexpensive to manufacture and can handle high transmitter power.

  10. Body conformal antennas for superficial hyperthermia: the impact of bending contact flexible microstrip applicators on their electromagnetic behavior.

    PubMed

    Correia, Davi; Kok, H Petra; de Greef, Martijn; Bel, Arjan; van Wieringen, Niek; Crezee, Johannes

    2009-12-01

    Hyperthermia is a powerful radiosensitizer for treatment of superficial tumors. This requires body conformal antennas with a power distribution as homogeneous as possible over the skin area. The contact flexible microstrip applicators (CFMA) operating at 434 MHz exist in several sizes, including the large size 3H and 5H. This paper investigates the behavior of the electromagnetic fields for the 3H and 5H CFMA in both flat and curved configurations, and the impact on performance parameters like the penetration depth (PD) and the effective heating depth (EHD). The underlying theory behind the electromagnetic behavior in curved situations is presented as well as numerical simulations of both flat and curved configurations. The results are compared to measurements of the electromagnetic field distributions in a cylindrical patient model. Due to their large size multimode solutions may exist, and our results confirm their existence. These multimode solutions affect both the power distribution and PD/EHD, with a dependence on applicator curvature. Therefore, the performance parameters like PD and EHD need to be carefully assessed when bending large size CFMA applicators to conform to the patient body. This conclusion also holds for other types of large size surface current applicators. PMID:19695983

  11. An Application of Artificial Neural Network to Compute the Resonant Frequency of E-Shaped Compact Microstrip Antennas

    NASA Astrophysics Data System (ADS)

    Akdagli, Ali; Toktas, Abdurrahim; Kayabasi, Ahmet; Develi, Ibrahim

    2013-09-01

    An application of artificial neural network (ANN) based on multilayer perceptrons (MLP) to compute the resonant frequency of E-shaped compact microstrip antennas (ECMAs) is presented in this paper. The resonant frequencies of 144 ECMAs with different dimensions and electrical parameters were firstly determined by using IE3D(tm) software based on the method of moments (MoM), then the ANN model for computing the resonant frequency was built by considering the simulation data. The parameters and respective resonant frequency values of 130 simulated ECMAs were employed for training and the remaining 14 ECMAs were used for testing the model. The computed resonant frequencies for training and testing by ANN were obtained with the average percentage errors (APE) of 0.257% and 0.523%, respectively. The validity and accuracy of the present approach was verified on the measurement results of an ECMA fabricated in this study. Furthermore, the effects of the slots loading method over the resonant frequency were investigated to explain the relationship between the slots and resonant frequency.

  12. Design And Simulation Of Microstrip Antenna Of 2.4 GHz Using CST

    NASA Astrophysics Data System (ADS)

    Thakur, O. P.; Kushwaha, Alok K.

    2011-12-01

    This article describes the design, fabrication and testing of micro strip patch antennas operating at 2.4 GHz. Consideration is given on practical design technique, including substrate selection and antenna measurements. It is emphasised to the radiation properties of the antennas—the radiation pattern and polarization purity. A micro strip patch antenna consists of a very thin metallic patch placed a small fraction of a wavelength above a conducting ground-plane. The patch and ground-plane are separated by a dielectric. The patch conductor is normally copper and can assume any shape, but simple geometries generally are used, and this simplifies the analysis and performance prediction. The patches are usually photo etched on the dielectric substrate. The substrate is usually non-magnetic. The relative permittivity of the substrate is normally in the region between 1 and 4, which enhances the fringing fields that account for radiation, but higher values may be used in special circumstances. Due to its simple geometry, the half wave rectangular patch is the most commonly used micro strip antenna. It is characterized by its length L, width w and thickness h. The simplest method of feeding the patch is by a coplanar micro strip line, also photo etched on the substrate. Coaxial feeds are also widely used.

  13. Technique for Radiometer and Antenna Array Calibration with a Radiated Noise Diode

    NASA Technical Reports Server (NTRS)

    Srinivasan, Karthik; Limaye, Ashutosh; Laymon, Charles; Meyer, Paul

    2009-01-01

    This paper presents a new technique to calibrate a microwave radiometer and antenna array system. This calibration technique uses a radiated noise source in addition to two calibration sources internal to the radiometer. The method accurately calibrates antenna arrays with embedded active devices (such as amplifiers) which are used extensively in active phased array antennas.

  14. The frequency response of phased-array antennas

    NASA Astrophysics Data System (ADS)

    Brock, B. C.

    1989-02-01

    The phased-array antenna will be examined from the point of view of effects caused by changes in frequency. Both simple linear arrays and the more complex conformal array are examined. For the conformal array, a comparison between a corporate-feed structure and a row series-feed structure is included. There are two primary effects which will be discussed: beam-pointing errors and distortion of large bandwidth signals. A formula for estimating the operating or tunable array bandwidth for narrow-bandwidth signals is derived. An expression for the wide-bandwidth-signal transfer function is also obtained and examined. It will be shown that the transfer function depends both on the array scan angle and the position within the mainbeam.

  15. The frequency response of phased-array antennas

    SciTech Connect

    Brock, B.C.

    1989-02-01

    The phased-array antenna will be examined from the point of view of effects caused by changes in frequency. Both simple linear arrays and the more complex conformal array are examined. For the conformal array, a comparison between a corporate-feed structure and a row series-feed structure is included. There are two primary effects which will be discussed: beam-pointing errors and distortion of large bandwidth signals. A formula for estimating the operating or tunable array bandwidth for narrow-bandwidth signals is derived. An expression for the wide-bandwidth-signal transfer function is also obtained and examined. It will be shown that the transfer function depends both on the array scan angle and the position within the mainbeam. 25 figs.

  16. Inflatably Deployed Membrane Waveguide Array Antenna for Space

    NASA Technical Reports Server (NTRS)

    Lichodziejewski, David; Cravey, Robin; Hopkins, Glenn

    2003-01-01

    As an alternative to parabolic antennas and Synthetic Aperture Radar (SAR) systems, waveguide arrays offer another method of providing RF transmit/receive communication apertures for spacecraft. The advantage of the membrane waveguide array concept, in addition to its lightweight and low packaged volume, is its inherent shape. Relative to parabolic antennas, the requirement to make an accurate doubly curved surface is removed. L'Garde and Langley Research Center (LaRC), are currently working in this area to develop lightweight waveguide array technologies utilizing thin film membrane structures. Coupled with an ultra-lightweight inflatably deployed rigidizable planar support structure, the system offers a very compelling technology in the fields of space-based radar, communications, and earth resource mapping.

  17. Out-of-band response of antenna arrays

    NASA Astrophysics Data System (ADS)

    Hill, David A.; Francis, Michael H.

    1987-11-01

    The response of antenna arrays to out-of-band frequencies has been analyzed using the effective-aperture approach. An average value of effective aperture can be obtained by averaging the incidence angle and the polarization of the incidence field. Far-field patterns have also been calculated by treating the array element excitations as random variables. The randomness in the element excitations causes a decrease in directivity and an increase in sidelobe level. Out-of-band measurements on a slotted-waveguide array confirm these trends.

  18. Algorithm for Aligning an Array of Receiving Radio Antennas

    NASA Technical Reports Server (NTRS)

    Rogstad, David

    2006-01-01

    A digital-signal-processing algorithm (somewhat arbitrarily) called SUMPLE has been devised as a means of aligning the outputs of multiple receiving radio antennas in a large array for the purpose of receiving a weak signal transmitted by a single distant source. As used here, aligning signifies adjusting the delays and phases of the outputs from the various antennas so that their relatively weak replicas of the desired signal can be added coherently to increase the signal-to-noise ratio (SNR) for improved reception, as though one had a single larger antenna. The method was devised to enhance spacecraft-tracking and telemetry operations in NASA's Deep Space Network (DSN); the method could also be useful in such other applications as both satellite and terrestrial radio communications and radio astronomy. Heretofore, most commonly, alignment has been effected by a process that involves correlation of signals in pairs. This approach necessitates the use of a large amount of hardware most notably, the N(N - 1)/2 correlators needed to process signals from all possible pairs of N antennas. Moreover, because the incoming signals typically have low SNRs, the delay and phase adjustments are poorly determined from the pairwise correlations. SUMPLE also involves correlations, but the correlations are not performed in pairs. Instead, in a partly iterative process, each signal is appropriately weighted and then correlated with a composite signal equal to the sum of the other signals (see Figure 1). One benefit of this approach is that only N correlators are needed; in an array of N much greater than 1 antennas, this results in a significant reduction of the amount of hardware. Another benefit is that once the array achieves coherence, the correlation SNR is N - 1 times that of a pair of antennas.

  19. Search space scanning with planar electronically-controlled array antennas

    NASA Astrophysics Data System (ADS)

    Hanle, E.

    The demands which radar installations have to satisfy are rising with increasing traffic density in the case of civil applications and a growing threat level in the case of the military sector. In many instances, these demands can only be met by adapting the value of the transmitted power to the traffic density or the magnitude of the threat. Such an approach requires the employment of computer-aided radar systems with electronically-controlled antennas. The considered systems have currently also advantages with respect to reliability and cost effectiveness. The present investigation is concerned with suitable procedures for the improvement of the energy management, taking into account mainly aspects of radar control and signal processing. The discussion is based on the consideration of a planar array antenna. Differences arising in connection with the use of other types of antennas are also briefly examined. The employment of an immobile radar antenna for ground-based airspace observation is considered. Attention is given to the appropriate selection of the width of the lobe, the scanning, the tilt of the antenna, and antenna performance characteristics.

  20. Performance evaluation of antenna arrays with noisy carrier reference

    NASA Technical Reports Server (NTRS)

    Yan, T. Y.; Clare, L. P.

    1981-01-01

    The performance evaluation of coherent receivers with noisy carrier references and multiple antennas is presented. The received signal is assumed to be residual carrier BPSK, with a PLL used for extracting the carrier. Explicit relationships between the error probabilities and the various system parameters are given. Specific results are given for the performance gain of combined carrier referencing over baseband only combining when the channel alignment process is ideal. A simple asymptotic expression for the performance gain is determined when the number of antennas used is increased without bound. Examples using Deep Space Network receivers illustrate the performance of each arraying structure.

  1. Spatial frequency multiplier with active linearly tapered slot antenna array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1994-01-01

    A frequency multiplier with active linearly tapered slot antennas (LTSA's) has been demonstrated at the second harmonic frequency. In each antenna element, a GaAs monolithic microwave integrated circuit (MMIC) distributed amplifier is integrated with two LTSA's. The multiplier has a very wide bandwidth and large dynamic range. The fundamental-to-second harmonic conversion efficiency is 8.1 percent. The spatially combined second harmonic signal is 50 dB above the noise level. The design is suitable for constructing a large array using monolithic integration techniques.

  2. Space Power Amplification with Active Linearly Tapered Slot Antenna Array

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1993-01-01

    A space power amplifier composed of active linearly tapered slot antennas (LTSA's) has been demonstrated and shown to have a gain of 30 dB at 20 GHz. In each of the antenna elements, a GaAs monolithic microwave integrated circuit (MMIC) three-stage power amplifier is integrated with two LTSA's. The LTSA and the MMIC power amplifier has a gain of 11 dB and power added efficiency of 14 percent respectively. The design is suitable for constructing a large array using monolithic integration techniques.

  3. 0.6-M Antennae for the Amiba Interferometry Array

    NASA Astrophysics Data System (ADS)

    Koch, P.; Raffin, P. A.; Proty Wu, J.-H.; et al.

    2006-10-01

    The Array for Microwave Background Anisotropy (AMiBA) is a hexapod telescope for astronomy. The fully steerable platform can accommodate up to 19 dishes. We present the design, simulation, manufacturing and performance verification for the 0.6m Cassegrain antennae. The primary and secondary mirrors are carbon fiber sandwich structures, manufactured by CoTec Inc., in Taichung, Taiwan. They are aluminium coated with a final surface rms of 20-30 and 10 μm, respectively. Simulated load conditions for the mirrors show maximum rms surface errors of less than 10 μm. The measured antenna beam pattern confirms the expected performance.

  4. Synthesis of Volumetric Ring Antenna Array for Terrestrial Coverage Pattern

    PubMed Central

    Reyna, Alberto; Panduro, Marco A.; Del Rio Bocio, Carlos

    2014-01-01

    This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X-Y, the positions of the rings on the plane X-Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction. PMID:24701150

  5. Estimating Transmitted-Signal Phase Variations for Uplink Array Antennas

    NASA Technical Reports Server (NTRS)

    Paal, Leslie; Mukai, Ryan; Vilntrotter, Victor; Cornish, Timothy; Lee, Dennis

    2009-01-01

    A method of estimating phase drifts of microwave signals distributed to, and transmitted by, antennas in an array involves the use of the signals themselves as phase references. The method was conceived as part of the solution of the problem of maintaining precise phase calibration required for proper operation of an array of Deep Space Network (DSN) antennas on Earth used for communicating with distant spacecraft at frequencies between 7 and 8 GHz. The method could also be applied to purely terrestrial phased-array radar and other radio antenna array systems. In the DSN application, the electrical lengths (effective signal-propagation path lengths) of the various branches of the system for distributing the transmitted signals to the antennas are not precisely known, and they vary with time. The variations are attributable mostly to thermal expansion and contraction of fiber-optic and electrical signal cables and to a variety of causes associated with aging of signal-handling components. The variations are large enough to introduce large phase drifts at the signal frequency. It is necessary to measure and correct for these phase drifts in order to maintain phase calibration of the antennas. A prior method of measuring phase drifts involves the use of reference-frequency signals separate from the transmitted signals. A major impediment to accurate measurement of phase drifts over time by the prior method is the fact that although DSN reference-frequency sources separate from the transmitting signal sources are stable and accurate enough for most DSN purposes, they are not stable enough for use in maintaining phase calibrations, as required, to within a few degrees over times as long as days or possibly even weeks. By eliminating reliance on the reference-frequency subsystem, the present method overcomes this impediment. In a DSN array to which the present method applies (see figure), the microwave signals to be transmitted are generated by exciters in a signal

  6. RF MEMS reconfigurable triangular patch antenna.

    SciTech Connect

    Nordquist, Christopher Daniel; Christodoulou, Christos George; Feldner, Lucas Matthew

    2005-01-01

    A Ka-band RF MEMS enabled frequency reconfigurable triangular microstrip patch antenna has been designed for monolithic integration with RF MEMS phase shifters to demonstrate a low-cost monolithic passive electronically scanned array (PESA). This paper introduces our first prototype reconfigurable triangular patch antenna currently in fabrication. The aperture coupled patch antenna is fabricated on a dual-layer quartz/alumina substrate using surface micromachining techniques.

  7. RF MEMS reconfigurable triangular patch antenna.

    SciTech Connect

    Christodoulou, Christos George; Nordquist, Christopher Daniel; Feldner, Lucas Matthew

    2005-07-01

    A Ka-band RF MEMS enabled frequency reconfigurable triangular microstrip patch antenna has been designed for monolithic integration with RF MEMS phase shifters to demonstrate a low-cost monolithic passive electronically scanned array (PESA). This paper introduces our first prototype reconfigurable triangular patch antenna currently in fabrication. The aperture coupled patch antenna is fabricated on a dual-layer quartz/alumina substrate using surface micromachining techniques.

  8. Input impedance of coaxially fed rectangular microstrip antenna on electrically thick substrate

    NASA Technical Reports Server (NTRS)

    Chen, Wei; Lee, Kai-Fong; Lee, R. Q.

    1993-01-01

    A full-wave spectral domain analysis has been used to obtain input-impedance results for a probe-fed rectangular-patch antenna, modeling the source as a magnetic-current frill. Multiple modes are used in the probe surface current to account for axial and azimuthal variations. It is established that maximum resistance is dependent on the substrate loss tangent. The axial variation of the probe current must be taken into account for substrate thicknesses greater than about 0.02 wavelengths.

  9. Human tracking using a two-element antenna array

    NASA Astrophysics Data System (ADS)

    Lin, Adrian; Ling, Hao

    2005-05-01

    We investigate the use of a low-cost, two-element receiving array for tracking human movements in indoor surveillance applications. Conventional direction of arrival (DOA) detection requires the use of an antenna array with multiple elements. Here we investigate the use of only two elements in the receiver array. The concept entails simultaneously resolving the Doppler frequencies of the returned signals from the moving targets and the DOA of the targets. Simulation is performed to demonstrate the concept. Both the monostatic and the bistatic scenario where the transmitter and the receiving array are placed at different locations are investigated. DOA errors and tolerances are analyzed for each scenario. An experimental system is constructed to test the concept. The system consists of a two-element receiver array operating at 2.4 GHz. Measurement results of various collection scenarios are presented.

  10. Cylindrical Antenna With Partly Adaptive Phased-Array Feed

    NASA Technical Reports Server (NTRS)

    Hussein, Ziad; Hilland, Jeff

    2003-01-01

    A proposed design for a phased-array fed cylindrical-reflector microwave antenna would enable enhancement of the radiation pattern through partially adaptive amplitude and phase control of its edge radiating feed elements. Antennas based on this design concept would be attractive for use in radar (especially synthetic-aperture radar) and other systems that could exploit electronic directional scanning and in which there are requirements for specially shaped radiation patterns, including ones with low side lobes. One notable advantage of this design concept is that the transmitter/ receiver modules feeding all the elements except the edge ones could be identical and, as a result, the antenna would cost less than in the cases of prior design concepts in which these elements may not be identical.

  11. Receiver Would Control Phasing of a Phased-Array Antenna

    NASA Technical Reports Server (NTRS)

    Dunn, Charles E.; Young, Lawrence E.

    2006-01-01

    In a proposed digital signal-processing technique, a radio receiver would control the phasing of a phased-array antenna to aim the peaks of the antenna radiation pattern toward desired signal sources while aiming the nulls of the pattern toward interfering signal sources. The technique was conceived for use in a Global Positioning System (GPS) receiver, for which the desired signal sources would be GPS satellites and typical interference sources would be terrestrial objects that cause multipath propagation. The technique could also be used to optimize reception in spread-spectrum cellular-telephone and military communication systems. During reception of radio signals in a conventional phased-array antenna system, received signals at their original carrier frequencies are phase-shifted, then combined by analog circuitry. The combination signal is then subjected to down-conversion and demodulation. In a system according to the proposed technique (see figure), the signal received by each antenna would be subjected to down-conversion, spread-spectrum demodulation, and correlation; this processing would be performed separately from, and simultaneously with, similar processing of signals received by the other antenna elements. Following analog down-conversion to baseband, the signals would be digitized, and all subsequent processing would be digital. In the digital process, residual carriers would be removed and each signal would be correlated with a locally generated model pseudorandum-noise code, all following normal GPS procedure. As part of this procedure, accumulated values would be added in software and the resulting signals would be phase-shifted in software by the amounts necessary to synthesize the desired antenna directional gain pattern of peaks and nulls. The principal advantage of this technique over the conventional radio-frequency-combining technique is that the parallel digital baseband processing of the signals from the various antenna elements would be

  12. Wide-Band, Wide-Scan Antenna For Circular Polarization

    NASA Technical Reports Server (NTRS)

    Huang, John

    1988-01-01

    Circular polarization generated by linearly polarized elements. Basic two-by-two subarray of antenna elements made of microstrip patches. Patches arranged in orthogonal pattern. Fed through different phase shifters so signal at feed points have same orthogonal relationship in phase. Antennas of this general type useful in communications and phased-array radar.

  13. Frequency translating phase conjugation circuit for active retrodirective antenna array

    NASA Astrophysics Data System (ADS)

    Chernoff, R.

    1980-11-01

    An active retrodirective antenna array which has central phasing from a reference antenna element through a "tree" structured network of transmission lines utilizes a number of phase conjugate circuits (PCCs) at each node and a phase reference regeneration circuit (PRR) at each node except the initial node. Each node virtually coincides with an element of the array. A PCC generates the exact conjugate phase of an incident signal using a phase locked loop which combines the phases in an up converter, divides the sum by 2 and mixes the result with the phase in a down converter for phase detection. The PRR extracts the phase from the conjugate phase. Both the PCC and the PRR are not only exact but also free from mixer degeneracy.

  14. Optimizing Satellite Communications With Adaptive and Phased Array Antennas

    NASA Technical Reports Server (NTRS)

    Ingram, Mary Ann; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Popovic, Zoya; Langley, John; Barott, William C.; Ahmed, M. Usman; Mandl, Dan

    2004-01-01

    A new adaptive antenna array architecture for low-earth-orbiting satellite ground stations is being investigated. These ground stations are intended to have no moving parts and could potentially be operated in populated areas, where terrestrial interference is likely. The architecture includes multiple, moderately directive phased arrays. The phased arrays, each steered in the approximate direction of the satellite, are adaptively combined to enhance the Signal-to-Noise and Interference-Ratio (SNIR) of the desired satellite. The size of each phased array is to be traded-off with the number of phased arrays, to optimize cost, while meeting a bit-error-rate threshold. Also, two phased array architectures are being prototyped: a spacefed lens array and a reflect-array. If two co-channel satellites are in the field of view of the phased arrays, then multi-user detection techniques may enable simultaneous demodulation of the satellite signals, also known as Space Division Multiple Access (SDMA). We report on Phase I of the project, in which fixed directional elements are adaptively combined in a prototype to demodulate the S-band downlink of the EO-1 satellite, which is part of the New Millennium Program at NASA.

  15. A multi-layer circularly polarized microstrip patch antenna with proximity coupling and increased gain

    NASA Technical Reports Server (NTRS)

    Zawadzki, M.

    2001-01-01

    Presented is a description of the single stacked element, and measured and calculated results at 2.56 GHz. Also included are measured results for the array, and calculated results of a stacked element for the required frequency-scaled version at 32 GHz.

  16. Land vehicle antennas for satellite mobile communications

    NASA Technical Reports Server (NTRS)

    Haddad, H. A.; Pieper, B. V.; Mckenna, D. B.

    1985-01-01

    The RF performance, size, pointing system, and cost were investigated concepts are: for a mechanically steered 1 x 4 tilted microstrip array, a mechanically steered fixed-beam conformal array, and an electronically steered conformal phased array. Emphasis is on the RF performance of the tilted 1 x 4 antenna array and methods for pointing the various antennas studied to a geosynchronous satellite. An updated version of satellite isolations in a two-satellite system is presented. Cost estimates for the antennas in quantities of 10,000 and 100,000 unites are summarized.

  17. Analysis of finite multifrequency slotted waveguide antenna arrays

    NASA Astrophysics Data System (ADS)

    Ponomarev, L. I.; Rud', S. V.; Ryzhikov, A. V.

    1988-02-01

    A model of a finite multifrequency slotted waveguide antenna array based on multimode waveguides is developed on the basis of an integral-equation method. Numerical-analysis results are presented which make it possible to assess the mutual distortions introduced in the radiation characteristics in each of the operating subbands. It is noted that these distortions can be minimized by a proper mutual arrangement of the slots as well as by an appropriate type of waveguide excitation.

  18. Delivering both sum and difference beam distributions to a planar monopulse antenna array

    DOEpatents

    Strassner, II, Bernd H.

    2015-12-22

    A planar monopulse radar apparatus includes a planar distribution matrix coupled to a planar antenna array having a linear configuration of antenna elements. The planar distribution matrix is responsive to first and second pluralities of weights applied thereto for providing both sum and difference beam distributions across the antenna array.

  19. 2-D scalable optical controlled phased-array antenna system

    NASA Astrophysics Data System (ADS)

    Chen, Maggie Yihong; Howley, Brie; Wang, Xiaolong; Basile, Panoutsopoulos; Chen, Ray T.

    2006-02-01

    A novel optoelectronically-controlled wideband 2-D phased-array antenna system is demonstrated. The inclusion of WDM devices makes a highly scalable system structure. Only (M+N) delay lines are required to control a M×N array. The optical true-time delay lines are combination of polymer waveguides and optical switches, using a single polymeric platform and are monolithically integrated on a single substrate. The 16 time delays generated by the device are measured to range from 0 to 175 ps in 11.6 ps. Far-field patterns at different steering angles in X-band are measured.

  20. Ultra wideband photonic control of an adaptive phased array antenna

    NASA Astrophysics Data System (ADS)

    Cox, Joseph L.; Zmuda, Henry; Li, Jian; Sforza, Pasquale M.

    2006-05-01

    This paper presents a new concept for a photonic implementation of a time reversed RF antenna array beamforming system. The process does not require analog to digital conversion to implement and is therefore particularly suited for high bandwidth applications. Significantly, propagation distortion due to atmospheric effects, clutter, etc. is automatically accounted for with the time reversal process. The approach utilizes the reflection of an initial interrogation signal from off an extended target to precisely time match the radiating elements of the array so as to re-radiate signals precisely back to the target's location. The backscattered signal(s) from the desired location is captured by each antenna and used to modulate a pulsed laser. An electrooptic switch acts as a time gate to eliminate any unwanted signals such as those reflected from other targets whose range is different from that of the desired location resulting in a spatial null at that location. A chromatic dispersion processor is used to extract the exact array parameters of the received signal location. Hence, other than an approximate knowledge of the steering direction needed only to approximately establish the time gating, no knowledge of the target position is required, and hence no knowledge of the array element time delay is required. Target motion and/or array element jitter is automatically accounted for. This paper presents the preliminary study of the photonic processor, analytical justification, and simulated results. The technology has a broad range of applications including aerospace and defense and in medical imaging.

  1. An Intelligent Fault Detection and Isolation Architecture for Antenna Arrays

    NASA Astrophysics Data System (ADS)

    Rahnamai, K.; Arabshahi, P.; Yan, T.-Y.; Pham, T.; Finley, S. G.

    1997-10-01

    This article describes a general architecture for fault modeling, diagnosis, and isolation of the DSN antenna array based on computationally intelligent techniques(neural networks and fuzzy logic). It encompasses a suite of intelligent test and diagnosis algorithms in software. By continuously monitoring the health of the highly complex and nonlinear array observables, the automated diagnosis software will be able to identify and isolate the most likely causes of system failure in cases of faulty operation. Furthermore, it will be able to recommend a series of corresponding corrective actions and effectively act as an automated real-time and interactive system supervisor. In so doing, it will enhance the array capability by reducing the operational workload, increasing science information availability, reducing the overall cost of operation by reducing system downtimes, improving risk management, and making mission planning much more reliable. Operation of this architecture is illustrated using examples from observables available from the 34-meter arraying task.

  2. Antenna arrays for producing plane whistler waves

    NASA Astrophysics Data System (ADS)

    Stenzel, Reiner; Urrutia, J. Manuel

    2015-11-01

    In a large uniform laboratory plasma helicon modes with mode numbers 1 - 8 have been excited. Using a circular phased array it is shown that positive and negative modes can propagate equally well. The phase fronts of helicons form Archimedian screw surfaces. The electromagnetic field carries linear momentum due to the axial propagation and angular momentum due to the azimuthal propagation. Associated with the orbital angular momentum is a transverse Doppler shift. It is demonstrated that a rapidly rotating ``receiver'' observes a different frequency than the wave. This implies that a rotating electron can undergo cyclotron resonance when moving against the field rotation. Analogous to the axial Doppler shift cyclotron damping and cyclotron instabilities are possible due to the field rotation in helicons. Since helicons exist in unbounded laboratory plasma they should also exist in space plasmas. The angular wave-particle interaction may be an alternate approach for the remedial of energetic electrons. Work supported by NSF/DOE.

  3. Ultra-Wideband, Dual-Polarized, Beam-Steering P-Band Array Antenna

    NASA Technical Reports Server (NTRS)

    duToit, Cornelis

    2014-01-01

    A dual-polarized, wide-bandwidth (200 MHz for one polarization, 100 MHz for the orthogonal polarization) antenna array at P-band was designed to be driven by NASA's EcoSAR digital beam former. EcoSAR requires two wide P-band antenna arrays mounted on the wings of an aircraft, each capable of steering its main beam up to 35deg off-boresight, allowing the twin radar beams to be steered at angles to the flight path. The science requirements are mainly for dual-polarization capability and a wide bandwidth of operation of up to 200 MHz if possible, but at least 100 MHz with high polarization port isolation and low cross-polarization. The novel design geometry can be scaled with minor modifications up to about four times higher or down to about half the current design frequencies for any application requiring a dual-polarized, wide-bandwidth steerable antenna array. EcoSAR is an airborne interferometric P-band synthetic aperture radar (SAR) research application for studying two- and three-dimensional fine-scale measurements of terrestrial ecosystem structure and biomass, which will ultimately aid in the broader study of the carbon cycle and climate change. The two 2×8 element Pband antenna arrays required by the system will be separated by a baseline of about 25 m, allowing for interferometry measurements. The wide 100-to- 200-MHz bandwidth dual-polarized beams employed will allow the determination of the amount of biomass and even tree height on the ground. To reduce the size of the patches along the boresight dimension in order to fit them into the available space, two techniques were employed. One technique is to add slots along the edges of each patch where the main electric currents are expected to flow, and the other technique is to bend the central part of the patch away from the ground plane. The latter also facilitates higher mechanical rigidity. The high port isolation of more than 40 dB was achieved by employing a highly symmetrical feed mechanism for each

  4. Self-radiation from arrays of niobium Josephson junctions embedded in the open resonator

    NASA Astrophysics Data System (ADS)

    Song, Fengbin; Müller, Franz; Behr, Ralf; Klushin, Alexander M.

    2010-10-01

    This paper focuses on self-radiation from arrays of Josephson junctions embedded in a quasi-optical resonator. The mechanism of coupling this radiation to the principal mode of the open resonator is illustrated using experiments and simulations with CST microwave studio software. Comparing the microstrips and dielectric resonators used as the antennas of the series arrays of discrete Josephson junctions, we demonstrate that the dielectric resonator antennas are more effective than microstrips.

  5. Pros and Cons of Using Arrays of Small Antennas Versus Large Single Dish Antennas for the Deep Space Network

    NASA Technical Reports Server (NTRS)

    Bagri, Durgadas S.

    2009-01-01

    This paper briefly describes pros and cons of using arrays of small antennas instead of large single dish antennas for spacecraft telemetry, command, and tracking (TT and C) - communications and navigation (C and N) - and science support that the Deep Space Network (DSN) normally provides. It considers functionality and performance aspects, mainly for TT and C, though it also considers science. It only briefly comments on the cost aspects that seem to favor arrays of small antennas over large single antennas, at least for receiving (downlinks).

  6. Distributed Antenna-Coupled TES for FIR Detectors Arrays

    NASA Technical Reports Server (NTRS)

    Day, Peter K.; Leduc, Henry G.; Dowell, C. Darren; Lee, Richard A.; Zmuidzinas, Jonas

    2007-01-01

    We describe a new architecture for a superconducting detector for the submillimeter and far-infrared. This detector uses a distributed hot-electron transition edge sensor (TES) to collect the power from a focal-plane-filling slot antenna array. The sensors lay directly across the slots of the antenna and match the antenna impedance of about 30 ohms. Each pixel contains many sensors that are wired in parallel as a single distributed TES, which results in a low impedance that readily matches to a multiplexed SQUID readout These detectors are inherently polarization sensitive, with very low cross-polarization response, but can also be configured to sum both polarizations. The dual-polarization design can have a bandwidth of 50The use of electron-phonon decoupling eliminates the need for micro-machining, making the focal plane much easier to fabricate than with absorber-coupled, mechanically isolated pixels. We discuss applications of these detectors and a hybridization scheme compatible with arrays of tens of thousands of pixels.

  7. Antenna array bandwidth enhancement using polymeric nanocomposite substrate

    NASA Astrophysics Data System (ADS)

    Muhamad, W. A. W.; Ngah, R.; Jamlos, M. F.; Soh, P. J.; Jamlos, M. A.; Lago, H.

    2016-04-01

    A 4 × 2 array antenna is developed using a new nanocomposite polymeric magneto-dielectric substrate. The permittivity and permeability factors have been accounted in designing the proposed array antenna at the frequency of 2.6 GHz. A pure polydimethylsiloxane (P-PDMS) (ɛ r = 2.7) solution is mixed with ferrite III oxide (μ r = 1.2) to generate this new nanocomposite polymeric magneto-dielectric (NPMD) substrate. The NPMD surface is then hardened and located in between two P-PDMS layers. The 4 × 2 radiating elements are immersed to the top of P-PDMS layer, while SMA coaxial feeder is fed from underneath the ground layer. This sealing technique enabled the proposed antenna to be waterproof and flexible. This combination contributes to bandwidth enhancement of 52.65 %, size miniaturization of 176 × 156 mm2 and high gain of 10.8 dB. The measured results show a good agreement with simulations.

  8. Mobile antenna development at JPL

    NASA Technical Reports Server (NTRS)

    Huang, J.; Jamnejad, V.; Densmore, A.; Tulintseff, A.; Thomas, R.; Woo, K.

    1993-01-01

    The Jet Propulsion Laboratory (JPL), under the sponsorship of NASA, has pioneered the development of land vehicle antennas for commercial mobile satellite communications. Several novel antennas have been developed at L-band frequencies for the Mobile Satellite (MSAT) program initiated about a decade ago. Currently, two types of antennas are being developed at K- and Ka-band frequencies for the ACTS (Advanced Communications Technology Satellite) Mobile Terminal (AMT) project. For the future, several hand-held antenna concepts are proposed for the small terminals of the Ka-band Personal Access Satellite System (PASS). For the L-band MSAT program, a number of omni-directional low-gain antennas, such as the crossed drooping-dipoles, the higher-order-mode circular microstrip patch, the quadrifilar helix, and the wrapped-around microstrip 'mast' array, have been developed for lower data rate communications. Several medium-gain satellite tracking antennas, such as the electronically scanned low-profile phased array, the mechanically steered tilted microstrip array, the mechanically steered low-profile microstrip Yagi array, and the hybrid electronically/mechanically steered low-profile array, have been developed for the MSAT's higher data rate and voice communications. To date, for the L-band vehicle application, JPL has developed the world's lowest-profile phased array (1.8 cm height), as well as the lowest-profile mechanically steered antenna (3.7 cm height). For the 20/30 GHz AMT project, a small mechanically steered elliptical reflector antenna with a gain of 23 dBi has recently been developed to transmit horizontal polarization at 30 GHz and receive vertical polarization at 20 GHz. Its hemispherical radome has a height of 10 cm and a base diameter of 23 cm. In addition to the reflector, a mechanically steered printed MMIC active array is currently being developed to achieve the same electrical requirements with a low profile capability. These AMT antenna developments

  9. Mutual coupling, channel model, and BER for curvilinear antenna arrays

    NASA Astrophysics Data System (ADS)

    Huang, Zhiyong

    This dissertation introduces a wireless communications system with an adaptive beam-former and investigates its performance with different antenna arrays. Mutual coupling, real antenna elements and channel models are included to examine the system performance. In a beamforming system, mutual coupling (MC) among the elements can significantly degrade the system performance. However, MC effects can be compensated if an accurate model of mutual coupling is available. A mutual coupling matrix model is utilized to compensate mutual coupling in the beamforming of a uniform circular array (UCA). Its performance is compared with other models in uplink and downlink beamforming scenarios. In addition, the predictions are compared with measurements and verified with results from full-wave simulations. In order to accurately investigate the minimum mean-square-error (MSE) of an adaptive array in MC, two different noise models, the environmental and the receiver noise, are modeled. The minimum MSEs with and without data domain MC compensation are analytically compared. The influence of mutual coupling on the convergence is also examined. In addition, the weight compensation method is proposed to attain the desired array pattern. Adaptive arrays with different geometries are implemented with the minimum MSE algorithm in the wireless communications system to combat interference at the same frequency. The bit-error-rate (BER) of systems with UCA, uniform rectangular array (URA) and UCA with center element are investigated in additive white Gaussian noise plus well-separated signals or random direction signals scenarios. The output SINR of an adaptive array with multiple interferers is analytically examined. The influence of the adaptive algorithm convergence on the BER is investigated. The UCA is then investigated in a narrowband Rician fading channel. The channel model is built and the space correlations are examined. The influence of the number of signal paths, number of the

  10. Computer-based designing of waveguide radiators of arbitrary cross section for antenna arrays

    NASA Astrophysics Data System (ADS)

    Voskresenskii, D. I.; Grinev, A. Iu.; Ilinskii, A. S.; Kotov, Iu. V.

    1980-02-01

    A multistep method is proposed for designing waveguide radiators for use in antenna arrays. A rigorous electrodynamic method for structure analysis is developed, along with a computer program and a numerical algorithm. The aperture performance of a quadruple-ridge rectangular waveguide in a phased array is examined, along with the directivity patterns of H-shaped, square, and circular radiators in antenna arrays.

  11. Phased-array-fed antenna configuration study, volume 2

    NASA Technical Reports Server (NTRS)

    Sorbello, R. M.; Zaghloul, A. I.; Lee, B. S.; Siddiqi, S.; Geller, B. D.

    1983-01-01

    Increased capacity in future satellite systems can be achieved through antenna systems which provide multiplicity of frequency reuses at K sub a band. A number of antenna configurations which can provide multiple fixed spot beams and multiple independent spot scanning beams at 20 GHz are addressed. Each design incorporates a phased array with distributed MMIC amplifiers and phasesifters feeding a two reflector optical system. The tradeoffs required for the design of these systems and the corresponding performances are presented. Five final designs are studied. In so doing, a type of MMIC/waveguide transition is described, and measured results of the breadboard model are presented. Other hardware components developed are described. This includes a square orthomode transducer, a subarray fed with a beamforming network to measure scanning performance, and another subarray used to study mutual coupling considerations. Discussions of the advantages and disadvantages of the final design are included.

  12. Optimization of the ITER Ion Cyclotron Heating Antenna Array

    NASA Astrophysics Data System (ADS)

    Ryan, P. M.; Swain, D. W.; Carter, M. D.; Taylor, D. J.; Bosia, G.; D'Ippolito, D. A.; Myra, J. R.

    1996-11-01

    The present design of the ITER ICH antenna array comprises two poloidal by four toroidal current elements in each of four ports. Each current element forms a resonant double loop (RDL) with power fed to a pretuned matchpoint on the strap; the matching is accomplished using slow-wave transmission lines as adjustable shorted-stub tuners on either end of the current strap. The power requirement is 12.5 MW per port over the frequency range of 40--70 MHz, with extended operation to 80 MHz desirable. The antenna design optimization process includes strap shaping to minimize strap voltages and rf E-fields along B-field lines, (2) frame/Faraday shield geometry design to improve plasma coupling, wave spectrum directivity, and phase control, and (3) Faraday shield/bumper geometry to minimize rf sheath-induced structure heating and impurity generation.

  13. Adaptive array antenna for satellite cellular and direct broadcast communications

    NASA Technical Reports Server (NTRS)

    Horton, Charles R.; Abend, Kenneth

    1993-01-01

    Adaptive phased-array antennas provide cost-effective implementation of large, light weight apertures with high directivity and precise beamshape control. Adaptive self-calibration allows for relaxation of all mechanical tolerances across the aperture and electrical component tolerances, providing high performance with a low-cost, lightweight array, even in the presence of large physical distortions. Beam-shape is programmable and adaptable to changes in technical and operational requirements. Adaptive digital beam-forming eliminates uplink contention by allowing a single electronically steerable antenna to service a large number of receivers with beams which adaptively focus on one source while eliminating interference from others. A large, adaptively calibrated and fully programmable aperture can also provide precise beam shape control for power-efficient direct broadcast from space. Advanced adaptive digital beamforming technologies are described for: (1) electronic compensation of aperture distortion, (2) multiple receiver adaptive space-time processing, and (3) downlink beam-shape control. Cost considerations for space-based array applications are also discussed.

  14. Electrical optimization of the ICH antenna array for ITER

    NASA Astrophysics Data System (ADS)

    Ryan, P. M.; Swain, D. W.; Carter, M. D.; Taylor, D. J.; Bosia, G.

    1997-04-01

    The present design of the ITER ICH antenna array comprises two poloidal by four toroidal current elements in each of four ports. Each current element forms a resonant double loop (RDL) with power fed to a pretuned matchpoint on the strap; the matching is accomplished using slow-wave transmission lines as adjustable shorted-stub tuners on other end of the current strap. The power requirement is 12.5 MW per port over the frequency range of 40-70 MHz, with extended operation to 80 MHz desirable. The antenna design optimization process includes (1) strap shaping to minimize strap voltages and rf E-fields along B-field lines and (2) frame/Faraday shield geometry design to improve plasma coupling, wave spectrum directivity, and phase control. For the ignited plasma parameters, the optimized array design delivers full power over the ranges of 40-80 MHz in frequency and 0° to 180° in phase. The maximum strap voltage is 41 kV and the maximum parallel E-field is 16 kV/cm for the worst case over these ranges. The array directivity for current drive operation is calculated to be close to 80%.

  15. Ka-band Dielectric Waveguide Antenna Array for Millimeter Wave Active Imaging System

    NASA Astrophysics Data System (ADS)

    Fang, Weihai; Fei, Peng; Nian, Feng; Yang, Yujie; Feng, Keming

    2014-11-01

    Ka-band compact dielectric waveguide antenna array for active imaging system is given. Antenna array with WR28 metal waveguide direct feeding is specially designed with small size, high gain, good radiation pattern, easy realization, low insertion loss and low mutual coupling. One practical antenna array for 3-D active imaging system is shown with theoretic analysis and experimental results. The mutual coupling of transmitting and receiving units is less than -30dB, the gain from 26.5GHz to 40GHz is (12-16) dB. The results in this paper provide guidelines for the designing of millimeter wave dielectric waveguide antenna array.

  16. SAR processing with stepped chirps and phased array antennas.

    SciTech Connect

    Doerry, Armin Walter

    2006-09-01

    Wideband radar signals are problematic for phased array antennas. Wideband radar signals can be generated from series or groups of narrow-band signals centered at different frequencies. An equivalent wideband LFM chirp can be assembled from lesser-bandwidth chirp segments in the data processing. The chirp segments can be transmitted as separate narrow-band pulses, each with their own steering phase operation. This overcomes the problematic dilemma of steering wideband chirps with phase shifters alone, that is, without true time-delay elements.

  17. Air shower measurements with the LOPES radio antenna array

    NASA Astrophysics Data System (ADS)

    Lopes Collaboration; Haungs, A.; Apel, W. D.; Arteaga, J. C.; Asch, T.; Auffenberg, J.; Badea, F.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Brüggemann, M.; Buchholz, P.; Buitink, S.; Cantoni, E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; de Souza, V.; di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Finger, M.; Fuhrmann, D.; Gemmeke, H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.; Heck, D.; Hörandel, J. R.; Horneffer, A.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Kickelbick, D.; Kolotaev, Y.; Krömer, O.; Kuijpers, J.; Lafebre, S.; Łuczak, P.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls, S.; Nigl, A.; Oehlschläger, J.; Over, S.; Petcu, M.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schröder, F.; Sima, O.; Singh, K.; Stümpert, M.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Walkowiak, W.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.; Zensus, J. A.; LOPES Collaboration

    2009-06-01

    LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from extensive air showers. Since radio waves suffer very little attenuation, radio measurements allow the detection of very distant or highly inclined showers. These waves can be recorded day and night, and provide a bolometric measure of the leptonic shower component. LOPES is designed as a digital radio interferometer using high bandwidths and fast data processing and profits from the reconstructed air shower observables of KASCADE-Grande. The LOPES antennas are absolutely amplitude calibrated allowing to reconstruct the electric field strength which can be compared with predictions from detailed Monte-Carlo simulations. We report about the analysis of correlations present in the radio signals measured by the LOPES 30 antenna array. Additionally, LOPES operates antennas of a different type (LOPESSTAR) which are optimized for an application at the Pierre Auger Observatory. Status, recent results of the data analysis and further perspectives of LOPES and the possible large scale application of this new detection technique are discussed.

  18. (abstract) A Ka-Band 0.5 m Circularily Polarized Microstrip Reflectarray

    NASA Technical Reports Server (NTRS)

    Huang, John

    1997-01-01

    The microstrip reflectarray antenna, being in the form of a flat reflector, has recently been investigated by several antenna researchers. This antenna, when compared to the conventional parabolic reflector, not only has the potential advantages of achieving smaller mass, smaller volume, simpler deployment mechanism, but also has the capability of scanning its main beam to larger angles from the broadside direction. Without any power divider and its associated large insertion loss, a phased reflectarray may not need the high cost T/R modules and can still remain to be an efficient array antenna.

  19. Broadband Uniplanar Microstrip to Slot-Line Transitions

    NASA Technical Reports Server (NTRS)

    Dib, Nihad I.; Simons, Rainee N.; Katehi, Linda P. B.

    1995-01-01

    New in line uniplanar microstrip-to-slotline transitions for MIC/MMIC and phased array slotline antenna applications are described. Such transactions are compact and suitable to be used in an open environment or inside a package or a multichip module. The transitions share the concept of using a balun which consists of two microstrip lines connected to a slotline through a pair of coupled microstrips. The transitions are studied theoretically using the finite difference time domain (FDTD) technique and measured experimentally using an HP8510C Network Analyzer. For a back-to-back configuration, an insertion loss of less than 1.3 dB per transition is achieved over a 40% 3-dB bandwidth with a minimum of 0.6 dB at the design frequency.

  20. Computer simulation of the effects of a distributed array antenna on synthetic aperture radar images

    NASA Technical Reports Server (NTRS)

    Estes, J. M.

    1985-01-01

    The ARL:UT orbital SAR simulation has been upgraded to use three-dimensional antenna gain patterns. This report describes the modifications and presents quantitative image analyses of a simulation using antenna patterns generated from the modeling of a distributed array antenna.

  1. The Digital Motion Control System for the Submillimeter Array Antennas

    NASA Astrophysics Data System (ADS)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.; Patel, N. A.; Blundell, R.; Christensen, R. D.; Diven, A. R.; Maute, J.; Plante, R. J.; Riddle, P.; Young, K. H.

    2013-09-01

    We describe the design and performance of the digital servo and motion control system for the 6-meter parabolic antennas of the Submillimeter Array (SMA) on Mauna Kea, Hawaii. The system is divided into three nested layers operating at a different, appropriate bandwidth. (1) A rack-mounted, real-time Unix system runs the position loop which reads the high resolution azimuth and elevation encoders and sends velocity and acceleration commands at 100 Hz to a custom-designed servo control board (SCB). (2) The microcontroller-based SCB reads the motor axis tachometers and implements the velocity loop by sending torque commands to the motor amplifiers at 558 Hz. (3) The motor amplifiers implement the torque loop by monitoring and sending current to the three-phase brushless drive motors at 20 kHz. The velocity loop uses a traditional proportional-integral-derivative (PID) control algorithm, while the position loop uses only a proportional term and implements a command shaper based on the Gauss error function. Calibration factors and software filters are applied to the tachometer feedback prior to the application of the servo gains in the torque computations. All of these parameters are remotely adjustable in the software. The three layers of the control system monitor each other and are capable of shutting down the system safely if a failure or anomaly occurs. The Unix system continuously relays the antenna status to the central observatory computer via reflective memory. In each antenna, a Palm Vx hand controller displays the complete system status and allows full local control of the drives in an intuitive touchscreen user interface. The hand controller can also be connected outside the cabin, a major convenience during the frequent reconfigurations of the interferometer. Excellent tracking performance ( 0.3‧‧ rms) is achieved with this system. It has been in reliable operation on 8 antennas for over 10 years and has required minimal maintenance.

  2. Quasi-optical antenna-mixer-array design for terahertz frequencies

    NASA Technical Reports Server (NTRS)

    Guo, Yong; Potter, Kent A.; Rutledge, David B.

    1992-01-01

    A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed.

  3. A finite element-boundary integral method for conformal antenna arrays on a circular cylinder

    NASA Technical Reports Server (NTRS)

    Kempel, Leo C.; Volakis, John L.; Woo, Alex C.; Yu, C. Long

    1992-01-01

    Conformal antenna arrays offer many cost and weight advantages over conventional antenna systems. In the past, antenna designers have had to resort to expensive measurements in order to develop a conformal array design. This is due to the lack of rigorous mathematical models for conformal antenna arrays, and as a result the design of conformal arrays is primarily based on planar antenna design concepts. Recently, we have found the finite element-boundary integral method to be very successful in modeling large planar arrays of arbitrary composition in a metallic plane. Herewith we shall extend this formulation for conformal arrays on large metallic cylinders. In this we develop the mathematical formulation. In particular we discuss the finite element equations, the shape elements, and the boundary integral evaluation, and it is shown how this formulation can be applied with minimal computation and memory requirements. The implementation shall be discussed in a later report.

  4. A finite element-boundary integral method for conformal antenna arrays on a circular cylinder

    NASA Technical Reports Server (NTRS)

    Kempel, Leo C.; Volakis, John L.

    1992-01-01

    Conformal antenna arrays offer many cost and weight advantages over conventional antenna systems. In the past, antenna designers have had to resort to expensive measurements in order to develop a conformal array design. This was due to the lack of rigorous mathematical models for conformal antenna arrays. As a result, the design of conformal arrays was primarily based on planar antenna design concepts. Recently, we have found the finite element-boundary integral method to be very successful in modeling large planar arrays of arbitrary composition in a metallic plane. We are extending this formulation to conformal arrays on large metallic cylinders. In doing so, we will develop a mathematical formulation. In particular, we discuss the finite element equations, the shape elements, and the boundary integral evaluation. It is shown how this formulation can be applied with minimal computation and memory requirements.

  5. Electromagnetically coupled microstrip dipoles

    NASA Astrophysics Data System (ADS)

    Oltman, H. G.; Huebner, D. A.

    1981-01-01

    A new class of printed circuit radiator consisting of a microstrip dipole electromagnetically coupled to a microstrip feed line is described. Several configurations which differ in bandwidth, efficiency, and construction simplicity are presented. A geometry which has been found to be optimum for many applications is noted. Radiation characteristics of both isolated elements and arrays of elements are examined. Experimental and theoretical results are presented.

  6. Microstrip amplitude-weighted wilkinson power dividers

    NASA Astrophysics Data System (ADS)

    Huck, K. D.

    1986-03-01

    Unequal-split reactive power dividers were examined for use in forming amplitude tapers for microstrip array antennas. Circuits with power ratios of up to 5.0 between arms were constructed on Rexolite substrate, for operation at 4.0 GHz and 7.5 GHz. The 4.0 GHz circuits were very accurate in forming the correct amplitude ratio between outputs, and in maintaining phase balance between outputs. Of those circuits designed for 7.5 GHz, only those with split ratios less than 2.5 worked correctly. This report includes a review of the theory, measured results, and recommendations for improved power dividers.

  7. Phase-locked laser array through global antenna mutual coupling

    DOE PAGESBeta

    Kao, Tsung -Yu; Reno, John L.; Hu, Qing

    2016-01-01

    Here, phase locking of an array of lasers is a highly effective way in beam shaping, to increase the output power, and to reduce lasing threshold. In this work, we present a novel phase-locking mechanism based on "antenna mutual coupling" wherein laser elements interact through far-field radiations with definite phase relations. This allows long-range global coupling among array elements to achieve robust 2-dimensional phase-locked laser array. The new scheme is ideal for lasers with deep sub-wavelength confined cavity such as nanolasers, where the divergent beam pattern could be used to form strong coupling among elements in the array. We experimentallymore » demonstrated such a scheme using sub-wavelength short-cavity surface-emitting lasers at terahertz frequency. More than 37 laser elements are phase-locked to each other, delivering up to 6.5 mW single-mode radiations at ~3 terahertz, with maximum 450-mW/A slope efficiency and near diffraction limit beam divergence.« less

  8. Phase-locked laser arrays through global antenna mutual coupling

    NASA Astrophysics Data System (ADS)

    Kao, Tsung-Yu; Reno, John L.; Hu, Qing

    2016-08-01

    Phase locking of an array of lasers is a highly effective method in beam shaping because it increases the output power and reduces the lasing threshold. Here, we show a conceptually novel phase-locking mechanism based on ‘antenna mutual coupling’ in which laser elements interact through far-field radiations with definite phase relations. This allows a long-range global coupling among the array elements to achieve a robust phase locking in two-dimensional laser arrays. The scheme is ideal for lasers with a deep subwavelength confined cavity, such as nanolasers, whose divergent beam patterns could be used to achieve a strong coupling among the elements in the array. We demonstrated experimentally such a scheme based on subwavelength short-cavity surface-emitting lasers at terahertz frequencies. More than 37 laser elements that span over ∼8 λo were phase locked to each other, and delivered up to 6.5 mW (in a pulsed operation) single-mode radiation at ∼3 THz, with a maximum 450 mW A–1 slope efficiency and a near-diffraction-limited beam divergence.

  9. Phase-locked laser array through global antenna mutual coupling

    SciTech Connect

    Kao, Tsung -Yu; Reno, John L.; Hu, Qing

    2016-01-01

    Here, phase locking of an array of lasers is a highly effective way in beam shaping, to increase the output power, and to reduce lasing threshold. In this work, we present a novel phase-locking mechanism based on "antenna mutual coupling" wherein laser elements interact through far-field radiations with definite phase relations. This allows long-range global coupling among array elements to achieve robust 2-dimensional phase-locked laser array. The new scheme is ideal for lasers with deep sub-wavelength confined cavity such as nanolasers, where the divergent beam pattern could be used to form strong coupling among elements in the array. We experimentally demonstrated such a scheme using sub-wavelength short-cavity surface-emitting lasers at terahertz frequency. More than 37 laser elements are phase-locked to each other, delivering up to 6.5 mW single-mode radiations at ~3 terahertz, with maximum 450-mW/A slope efficiency and near diffraction limit beam divergence.

  10. The DESDynI Synthetic Aperture Radar Array-Fed Reflector Antenna

    NASA Technical Reports Server (NTRS)

    Chamberlain, Neil; Ghaemi, Hirad; Giersch, Louis; Harcke, Leif; Hodges, Richard; Hoffman, James; Johnson, William; Jordan, Rolando; Khayatian, Behrouz; Rosen, Paul; Sadowy, Gregory; Shaffer, Scott; Shen, Yuhsyen; Veilleux, Louise; Wu, Patrick

    2010-01-01

    DESDynI is a mission being developed by NASA with radar and lidar instruments for Earth-orbit remote sensing. This paper focuses on the design of a largeaperture antenna for the radar instrument. The antenna comprises a deployable reflector antenna and an active switched array of patch elements fed by transmit/ receive modules. The antenna and radar architecture facilitates a new mode of synthetic aperture radar imaging called 'SweepSAR'. A system-level description of the antenna is provided, along with predictions of antenna performance.

  11. Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry

    NASA Astrophysics Data System (ADS)

    Bock, James

    2014-01-01

    We are developing high-sensitivity millimeter-wave detector arrays for measuring the polarization of the cosmic microwave background (CMB). This development is directed to advance the technology readiness of the Inflation Probe mission in NASA's Physics of the Cosmos program. The Inflation Probe is a fourth-generation CMB satellite that will measure the polarization of the CMB to astrophysical limits, characterizing the inflationary polarization signal, mapping large-scale structure based on polarization induced by gravitational lensing, and mapping Galactic magnetic fields through measurements of polarized dust emission. The inflationary polarization signal is produced by a background of gravitational waves from the epoch of inflation, an exponential expansion of space-time in the early universe, with an amplitude that depends on the physical mechanism producing inflation. The inflationary polarization signal may be distinguished by its unique 'B-mode' vector properties from polarization from the density variations that predominantly source CMB temperature anisotropy. Mission concepts for the Inflation Probe are being developed in the US, Europe and Japan. The arrays are based on planar antennas that provide integral beam collimation, polarization analysis, and spectral band definition in a compact lithographed format that eliminates discrete fore-optics such as lenses and feedhorns. The antennas are coupled to transition-edge superconducting bolometers, read out with multiplexed SQUID current amplifiers. The superconducting sensors and readouts developed in this program share common technologies with NASA X-ray and FIR detector applications. Our program targets developments required for space observations, and we discuss our technical progress over the past two years and plans for future development. We are incorporating arrays into active sub-orbital and ground-based experiments, which advance technology readiness while producing state of the art CMB

  12. Orthogonal feeding techniques for tapered slot antennas

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Simons, Rainee N.

    1998-01-01

    For array of "brick" configuration there are electrical and mechanical advantages to feed the antenna with a feed on a substrate perpendicular to the antenna substrate. Different techniques have been proposed for exciting patch antennas using such a feed structure.Rncently, an aperture-coupled dielectric resonator antenna using a perpendicular feed substrate has been demonstrated to have very good power coupling efficiency. For a two-dimensional rectangular array with tapered slot antenna elements, a power combining network on perpendicular substrate is generally required to couple power to or from the array. In this paper, we will describe two aperture-coupled techniques for coupling microwave power from a linearly tapered slot antenna (LTSA) to a microstrip feed on a perpendicular substrate. In addition, we will present measured results for return losses and radiation patterns.

  13. Considerations for millimeter wave printed antennas

    NASA Technical Reports Server (NTRS)

    Pozar, D. M.

    1983-01-01

    Calculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would be the case for printed antennas at millimeter wave frequencies. Printed dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, and gallium arsenide substrates are considered. Data are given for resonant length, resonant resistance, bandwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. Also presented is an optimization procedure for maximizing or minimizing power launched into surface waves from a multielement printed antenna array. The data are calculated by a moment method solution.

  14. Antenna coupled detectors for 2D staring focal plane arrays

    NASA Astrophysics Data System (ADS)

    Gritz, Michael A.; Kolasa, Borys; Lail, Brian; Burkholder, Robert; Chen, Leonard

    2013-06-01

    Millimeter-wave (mmW)/sub-mmW/THz region of the electro-magnetic spectrum enables imaging thru clothing and other obscurants such as fog, clouds, smoke, sand, and dust. Therefore considerable interest exists in developing low cost millimeter-wave imaging (MMWI) systems. Previous MMWI systems have evolved from crude mechanically scanned, single element receiver systems into very complex multiple receiver camera systems. Initial systems required many expensive mmW integrated-circuit low-noise amplifiers. In order to reduce the cost and complexity of the existing systems, attempts have been made to develop new mmW imaging sensors employing direct detection arrays. In this paper, we report on Raytheon's recent development of a unique focal plane array technology, which operates broadly from the mmW through the sub-mmW/THz region. Raytheon's innovative nano-antenna based detector enables low cost production of 2D staring mmW focal plane arrays (mmW FPA), which not only have equivalent sensitivity and performance to existing MMWI systems, but require no mechanical scanning.

  15. MSAT-X electronically steered phased array antenna system

    NASA Technical Reports Server (NTRS)

    Chung, H. H.; Foy, W.; Schaffner, G.; Pagels, W.; Vayner, M.; Nelson, J.; Peng, S. Y.

    1988-01-01

    A low profile electronically steered phased array was successfully developed for the Mobile Satellite Experiment Program (MSAT-X). The newly invented cavity-backed printed crossed-slot was used as the radiating element. The choice of this element was based on its low elevation angle gain coverage and low profile. A nineteen-way radial type unequal power divider and eighteen three-bit diode phase shifters constitute the beamformer module which is used to scan the beams electronically. A complete hybrid mode pointing system was also developed. The major features of the antenna system are broad coverage, low profile, and fast acquisition and tracking performance, even under fading conditions. Excellent intersatellite isolation (better than 26 dB) was realized, which will provide good quality mobile satellite communication in the future.

  16. Photonic spin-controlled multifunctional shared-aperture antenna array.

    PubMed

    Maguid, Elhanan; Yulevich, Igor; Veksler, Dekel; Kleiner, Vladimir; Brongersma, Mark L; Hasman, Erez

    2016-06-01

    The shared-aperture phased antenna array developed in the field of radar applications is a promising approach for increased functionality in photonics. The alliance between the shared-aperture concepts and the geometric phase phenomenon arising from spin-orbit interaction provides a route to implement photonic spin-control multifunctional metasurfaces. We adopted a thinning technique within the shared-aperture synthesis and investigated interleaved sparse nanoantenna matrices and the spin-enabled asymmetric harmonic response to achieve helicity-controlled multiple structured wavefronts such as vortex beams carrying orbital angular momentum. We used multiplexed geometric phase profiles to simultaneously measure spectrum characteristics and the polarization state of light, enabling integrated on-chip spectropolarimetric analysis. The shared-aperture metasurface platform opens a pathway to novel types of nanophotonic functionality. PMID:27103668

  17. Photonic spin-controlled multifunctional shared-aperture antenna array

    NASA Astrophysics Data System (ADS)

    Maguid, Elhanan; Yulevich, Igor; Veksler, Dekel; Kleiner, Vladimir; Brongersma, Mark L.; Hasman, Erez

    2016-06-01

    The shared-aperture phased antenna array developed in the field of radar applications is a promising approach for increased functionality in photonics. The alliance between the shared-aperture concepts and the geometric phase phenomenon arising from spin-orbit interaction provides a route to implement photonic spin-control multifunctional metasurfaces. We adopted a thinning technique within the shared-aperture synthesis and investigated interleaved sparse nanoantenna matrices and the spin-enabled asymmetric harmonic response to achieve helicity-controlled multiple structured wavefronts such as vortex beams carrying orbital angular momentum. We used multiplexed geometric phase profiles to simultaneously measure spectrum characteristics and the polarization state of light, enabling integrated on-chip spectropolarimetric analysis. The shared-aperture metasurface platform opens a pathway to novel types of nanophotonic functionality.

  18. Ultra-Wideband Tapered Slot Antenna Arrays with Parallel-Plate Waveguides

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Satoshi; Miyashita, Hiroaki; Takahashi, Toru; Otsuka, Masataka; Konishi, Yoshihiko

    Owing to their ultra-wideband characteristics, tapered slot antennas (TSAs) are used as element antennas in wideband phased arrays. However, when the size of a TSA is reduced in order to prevent the generation of a grating lobe during wide-angle beam scanning, the original ultra-wideband characteristics are degraded because of increased reflections from the ends of the tapered slot aperture. To overcome this difficulty, we propose a new antenna structure in which parallel-plate waveguides are added to the TSA. The advantage of this new structure is that the reflection characteristics of individual antenna elements are not degraded even if the width of the antenna aperture is very small, i.e., approximately one-half the wavelength of the highest operating frequency. In this study, we propose a procedure for designing the new antenna through numerical simulations by using the FDTD method. In addition, we verify the performance of the antenna array by experiments.

  19. Fully Printed High-Frequency Phased-Array Antenna on Flexible Substrate

    NASA Technical Reports Server (NTRS)

    Chen, Yihong; Lu, Xuejun

    2010-01-01

    To address the issues of flexible electronics needed for surface-to-surface, surface-to-orbit, and back-to-Earth communications necessary for manned exploration of the Moon, Mars, and beyond, a room-temperature printing process has been developed to create active, phased-array antennas (PAAs) on a flexible Kapton substrate. Field effect transistors (FETs) based on carbon nanotubes (CNTs), with many unique physical properties, were successfully proven feasible for phased-array antenna systems. The carrier mobility of an individual CNT is estimated to be at least 100,000 sq cm/V(dot)s. The CNT network in solution has carrier mobility as high as 46,770 sq cm/V(dot)s, and has a large current-density carrying capacity of approx. 1,000 mA/sq cm , which corresponds to a high carrying power of over 2,000 mW/ sq cm. Such high carrier mobility, and large current carrying capacity, allows the achievement of high-speed (>100 GHz), high-power, flexible electronic circuits that can be monolithically integrated on NASA s active phasedarray antennas for various applications, such as pressurized rovers, pressurized habitats, and spacesuits, as well as for locating beacon towers for lunar surface navigation, which will likely be performed at S-band and attached to a mobile astronaut. A fully printed 2-bit 2-element phasedarray antenna (PAA) working at 5.6 GHz, incorporating the CNT FETs as phase shifters, is demonstrated. The PAA is printed out at room temperature on 100-mm thick Kapton substrate. Four CNT FETs are printed together with microstrip time delay lines to function as a 2-bit phase shifter. The FET switch exhibits a switching speed of 0.2 ns, and works well for a 5.6-GHz RF signal. The operating frequency is measured to be 5.6 GHz, versus the state-of-the-art flexible FET operating frequency of 52 MHz. The source-drain current density is measured to be over 1,000 mA/sq cm, while the conventional organic FETs, and single carbon nanotube-based FETs, are typically in the m

  20. Prediction of heating patterns of a microwave interstitial antenna array at various insertion depths.

    PubMed

    Zhang, Y; Joines, W T; Oleson, J R

    1991-01-01

    Measurements made on the interstitial microwave antennas used for hyperthermia cancer therapy indicate that the heating patterns vary with the insertion depths (defined as the distance from the antenna tip to air-tissue interface). The antennas are made of thin coaxial cables with a radiation gap or gaps on the outer conductor. The antennas are inserted into small polypropylene catheters implanted in the tumour volume. This type of antenna may be simulated as an asymmetric dipole with one arm being the tip section consisting of the expanded extension of the inner conductor, and the other arm being the section of the outer conductor from the gap to the insertion point (air-tissue interface). We use four of the antennas to form a 2 cm x 2 cm array. The antennas are positioned on the corners of a 2 cm square. Measurements on both single antennas and multi-antenna arrays show that the maximum heating is not stationary with position along the antenna when the depth of insertion is changed. This paper investigates the theoretical prediction of the changes in heating patterns of interstitial microwave antennas at different insertion depths. Each of the antennas in the array is simulated as an asymmetric dipole. The SAR (specific absorption rate) is computed by using the insulated dipole theory. The temperature distribution in absence of perfusion is obtained through a thermal simulation routine to convert the SAR pattern into the temperature pattern. Excellent qualitative agreement is found between the theoretical heating pattern and the measured pattern in a non-perfused phantom on a 2 cm x 2 antenna array. Since the insertion depths of the interstitial antennas are different from patient to patient, it is recommended that simulation of the heating be done before treatments, to confirm the delivery of power to the target region. PMID:2051073

  1. Active feed array compensation for reflector antenna surface distortions. Ph.D. Thesis - Akron Univ., Ohio

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.

    1988-01-01

    The feasibility of electromagnetic compensation for reflector antenna surface distortions is investigated. The performance characteristics of large satellite communication reflector antenna systems degrade as the reflector surface distorts, mainly due to thermal effects from solar radiation. The technique developed can be used to maintain the antenna boresight directivity and sidelobe level independent of thermal effects on the reflector surface. With the advent of monolithic microwave integrated circuits (MMIC), a greater flexibility in array fed reflector antenna systems can be achieved. MMIC arrays provide independent control of amplitude and phase for each of the many radiating elements in the feed array. By assuming a known surface distortion profile, a simulation study is carried out to examine the antenna performance as a function of feed array size and number of elements. Results indicate that the compensation technique can effectively control boresight directivity and sidelobe level under peak surface distortion in the order of tenth of a wavelength.

  2. Lattice resonances in antenna arrays for liquid sensing in the terahertz regime.

    PubMed

    Ng, B; Hanham, S M; Giannini, V; Chen, Z C; Tang, M; Liew, Y F; Klein, N; Hong, M H; Maier, S A

    2011-07-18

    Terahertz antenna arrays supporting narrow lattice resonances are proposed as an alternative sensor-on-chip approach to liquid sensing. An array of metallic rectangular antennas fabricated on a polyethylene naphthalate (PEN) substrate is used to demonstrate the sensing of a number of fluids. Good agreement is shown between experiment and simulation with Q-factors of around 20 and a figure-of-merit (FOM) of 3.80 being achieved. Liquid sensing with antenna arrays is simple both in terms of fabrication and setup. The working frequency can be tuned with a suitable choice of substrates and array parameters. The nature of the lattice resonance means that the whole sample is used to provide the conditions required for resonance occurrence, eliminating the need to preferentially locate the sample in small areas of high field concentration. The antenna arrays could also potentially be coupled with a microfluidic system for in situ sensing or used in a reflection setup. PMID:21934827

  3. Experimental Study on MIMO Performance of Modulated Scattering Antenna Array in Indoor Environment

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Chen, Qiang; Yuan, Qiaowei; Sawaya, Kunio

    The modulated scattering antenna array (MSAA) is composed of one normal antenna element and several modulated scattering elements (MSEs). In this paper, a 2-element MSAA is used as the receiving antenna in a 2 × 2 multiple input multiple output (MIMO) system. MIMO performance of MSAA with various array spacing is measured to investigate the relation between the array spacing and the MIMO performance of the MSAA experimentally in the non-line-of-sight (NLOS) indoor environment. It is found that the error vector magnitude (EVM) and the channel capacity, which reflect MIMO performance, can be affected by the array spacing. The measured results of the MSAA were compared with that of two-dipole antenna array at the same condition.

  4. Low-Cost Phased Array Antenna for Sounding Rockets, Missiles, and Expendable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Mullinix, Daniel; Hall, Kenneth; Smith, Bruce; Corbin, Brian

    2012-01-01

    A low-cost beamformer phased array antenna has been developed for expendable launch vehicles, rockets, and missiles. It utilizes a conformal array antenna of ring or individual radiators (design varies depending on application) that is designed to be fed by the recently developed hybrid electrical/mechanical (vendor-supplied) phased array beamformer. The combination of these new array antennas and the hybrid beamformer results in a conformal phased array antenna that has significantly higher gain than traditional omni antennas, and costs an order of magnitude or more less than traditional phased array designs. Existing omnidirectional antennas for sounding rockets, missiles, and expendable launch vehicles (ELVs) do not have sufficient gain to support the required communication data rates via the space network. Missiles and smaller ELVs are often stabilized in flight by a fast (i.e. 4 Hz) roll rate. This fast roll rate, combined with vehicle attitude changes, greatly increases the complexity of the high-gain antenna beam-tracking problem. Phased arrays for larger ELVs with roll control are prohibitively expensive. Prior techniques involved a traditional fully electronic phased array solution, combined with highly complex and very fast inertial measurement unit phased array beamformers. The functional operation of this phased array is substantially different from traditional phased arrays in that it uses a hybrid electrical/mechanical beamformer that creates the relative time delays for steering the antenna beam via a small physical movement of variable delay lines. This movement is controlled via an innovative antenna control unit that accesses an internal measurement unit for vehicle attitude information, computes a beam-pointing angle to the target, then points the beam via a stepper motor controller. The stepper motor on the beamformer controls the beamformer variable delay lines that apply the appropriate time delays to the individual array elements to properly

  5. Antenna array connections for efficient performance of distributed microbolometers in the IR.

    PubMed

    Silva-López, Manuel; Cuadrado, Alexander; Llombart, Nuria; Alda, Javier

    2013-05-01

    Optical antennas and resonant structures have been extensively investigated due to its potential for electromagnetic detection and energy harvesting applications. However their integration into large arrays and the role of connection lines between individual antennas has drawn little attention. This is necessary if we want to exploit its potential constructively and to enable economical large-scale fabrication. In this contribution we point out some features that an efficient antenna array should address. Experimental measurements on aluminum microbolometers are compared to electromagnetic simulations, it is shown that the finite size of a real array and the interconnection lines interact and affect the global performance. PMID:23669943

  6. Mechanical Development of a Very Non-Standard Patch Array Antenna for Extreme Environments

    NASA Technical Reports Server (NTRS)

    Hughes, Richard; Chamberlain, Neil; Jakoboski, Julie; Petkov, Mihail

    2012-01-01

    This paper describes the mechanical development of patch antenna arrays for the Juno mission. The patch arrays are part of a six-frequency microwave radiometer instrument that will be used to measure thermal emissions from Jupiter. The very harsh environmental conditions in Jupiter orbit, as well as a demanding launch environment, resulted in a design that departs radically from conventional printed circuit patch antennas. The paper discusses the development and qualification of the Juno patch array antennas, with emphasis on the materials approach that was devised to mitigate the effects of electron charging in Jupiter orbit.

  7. Antenna coupled Kinetic Inductance arrays for space and ground based imaging arrays

    NASA Astrophysics Data System (ADS)

    Yates, S. J. C.; Baselmans, J. J. A.; Baryshev, A. M.; Neto, A.; Gerini, G.; Barends, R.; Lankwarden, Y. J. Y.

    2009-12-01

    Very large arrays of Microwave Kinetic Inductance Detectors (MKIDs) have the potential to revolutionize ground and space based astronomy. They can offer in excess of 10000 pixels with large dynamic range and very high sensitivity in combination with very efficient frequency division multiplexing at GHz frequencies. In this paper we present the development for a ~100 pixel MKID demonstration array based upon an single pixel consisting of an integrated MKID-antenna detector, with the antenna placed in the second focus of an elliptical Si lens. The design presented can be scaled to any frequency between 80 GHz and >5 THz because there is no need for superconducting structures that become lossy at frequencies above the gap frequency of the materials used. We present measurements of the optical coupling efficiency, sensitivity and discuss array development. We have obtained a dark sensitivity of 7×10-19W/Hz1/2 using 100 nm thick A1 devices and an optical coupling efficiency of 35% referring to the power of a single polarization optical signal in front of the Si lens of the detector.

  8. Low Average Sidelobe Slot Array Antennas for Radiometer Applications

    NASA Technical Reports Server (NTRS)

    Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

    2012-01-01

    In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E

  9. Yagi-Uda optical antenna array collimated laser based on surface plasmons

    NASA Astrophysics Data System (ADS)

    Ma, Long; Lin, Jie; Ma, Yuan; Liu, Bin; Tan, Jiubin; Jin, Peng

    2016-06-01

    The divergence and directivity of a laser with a periodic Yagi-Uda optical antenna array modulated surface are investigated by finite element method. The nanoparticle optical antenna arrays are optimized to achieve the high directivity and the small divergence by using of Helmholtz's reciprocity theorem. When the nanoparticle antenna replaced by a Yagi-Uda antenna with same size, the directivity and the signal-to-noise ratio of the modulated laser beam are notably enhanced. The main reason is that the directors of the Yagi-Uda antennas induce more energy to propagate towards the antenna transmitting direction. The results can provide valuable guidelines in designing collimated laser, which can be widely applied in the field of biologic detection, spatial optical communication and optical measurement.

  10. Parasitic antenna effect in terahertz plasmon detector array for real-time imaging system

    NASA Astrophysics Data System (ADS)

    Yang, Jong-Ryul; Lee, Woo-Jae; Ryu, Min Woo; Rok Kim, Kyung; Han, Seong-Tae

    2015-10-01

    The performance uniformity of each pixel integrated with a patch antenna in a terahertz plasmon detector array is very important in building the large array necessary for a real-time imaging system. We found a parasitic antenna effect in the terahertz plasmon detector whose response is dependent on the position of the detector pixel in the illumination area of the terahertz beam. It was also demonstrated that the parasitic antenna effect is attributed to the physical structure consisting of signal pads, bonding wires, and interconnection lines on a chip and a printed circuit board. Experimental results show that the performance of the detector pixel is determined by the sum of the effects of each parasitic antenna and the on-chip integrated antenna designed to detect signals at the operating frequency. The parasitic antenna effect can be minimized by blocking the interconnections with a metallic shield.

  11. Directional antenna array (DAA) for communications, control, and data link protection

    NASA Astrophysics Data System (ADS)

    Molchanov, Pavlo A.; Contarino, Vincent M.

    2013-06-01

    A next generation of Smart antennas with point-to-point communication and jam, spoof protection capability by verification of spatial position is offered. A directional antenna array (DAA) with narrow irradiation beam provides counter terrorism protection for communications, data link, control and GPS. Communications are "invisible" to guided missiles because of 20 dB smaller irradiation outside the beam and spatial separation. This solution can be implemented with current technology. Directional antennas have higher gain and can be multi-frequency or have wide frequency band in contrast to phase antenna arrays. This multi-directional antenna array provides a multi-functional communication network and simultaneously can be used for command control, data link and GPS.

  12. Phased-array-fed antenna configuration study. Volume 1: Technology assessment

    NASA Technical Reports Server (NTRS)

    Sorbello, R. M.; Zaghloul, A. I.; Lee, B. S.; Siddiqi, S.; Geller, B. D.; Gerson, H. I.; Srinivas, D. N.

    1983-01-01

    The status of the technologies for phased-array-fed dual reflector systems is reviewed. The different aspects of these technologies, including optical performances, phased array systems, problems encountered in phased array design, beamforming networks, MMIC design and its incorporation into waveguide systems, reflector antenna structures, and reflector deployment mechanisms are addressed.

  13. System performance and performance enhancement relative to element position location errors for distributed linear antenna arrays

    NASA Astrophysics Data System (ADS)

    Adrian, Andrew

    For the most part, antenna phased arrays have traditionally been comprised of antenna elements that are very carefully and precisely placed in very periodic grid structures. Additionally, the relative positions of the elements to each other are typically mechanically fixed as best as possible. There is never an assumption the relative positions of the elements are a function of time or some random behavior. In fact, every array design is typically analyzed for necessary element position tolerances in order to meet necessary performance requirements such as directivity, beamwidth, sidelobe level, and beam scanning capability. Consider an antenna array that is composed of several radiating elements, but the position of each of the elements is not rigidly, mechanically fixed like a traditional array. This is not to say that the element placement structure is ignored or irrelevant, but each element is not always in its relative, desired location. Relative element positioning would be analogous to a flock of birds in flight or a swarm of insects. They tend to maintain a near fixed position with the group, but not always. In the antenna array analog, it would be desirable to maintain a fixed formation, but due to other random processes, it is not always possible to maintain perfect formation. This type of antenna array is referred to as a distributed antenna array. A distributed antenna array's inability to maintain perfect formation causes degradations in the antenna factor pattern of the array. Directivity, beamwidth, sidelobe level and beam pointing error are all adversely affected by element relative position error. This impact is studied as a function of element relative position error for linear antenna arrays. The study is performed over several nominal array element spacings, from lambda to lambda, several sidelobe levels (20 to 50 dB) and across multiple array illumination tapers. Knowing the variation in performance, work is also performed to utilize a minimum

  14. Quasi-isotropic VHF antenna array design study for the International Ultraviolet Explorer satellite

    NASA Technical Reports Server (NTRS)

    Raines, J. K.

    1975-01-01

    Results of a study to design a quasi-isotropic VHF antenna array for the IUE satellite are presented. A free space configuration was obtained that has no nulls deeper than -6.4 dbi in each of two orthogonal polarizations. A computer program named SOAP that analyzes the electromagnetic interaction between antennas and complicated conducting bodies, such as satellites was developed.

  15. State-of-the-art and trends of Ground-Penetrating Radar antenna arrays

    NASA Astrophysics Data System (ADS)

    Vescovo, Roberto; Pajewski, Lara; Tosti, Fabio

    2016-04-01

    The aim of this contribution is to offer an overview on the antenna arrays for GPR systems, current trends and open issues. Antennas are a critical hardware component of a radar system, dictating its performance in terms of capability to detect targets. Nevertheless, most of the research efforts in the Ground-Penetrating Radar (GPR) area focus on the use of this imaging technique in a plethora of different applications and on the improvement of modelling/inversion/processing techniques, whereas a limited number of studies deal with technological issues related to the design of novel systems, including the synthesis, optimisation and characterisation of advanced antennas. Even fewer are the research activities carried out to develop innovative antenna arrays. GPR antennas operate in a strongly demanding environment and should satisfy a number of requirements, somehow unique and very different than those of conventional radar antennas. The same applies to GPR antenna arrays. The first requirement is an ultra-wide frequency band: the radar has to transmit and receive short-duration time-domain waveforms, in the order of a few nanoseconds, the time-duration of the emitted pulses being a trade-off between the desired radar resolution and penetration depth. Furthermore, GPR antennas should have a linear phase characteristic over the whole operational frequency range, predictable polarisation and gain. Due to the fact that a subsurface imaging system is essentially a short-range radar, the coupling between transmitting and receiving antennas has to be low and short in time. GPR antennas should have quick ring-down characteristics, in order to prevent masking of targets and guarantee a good resolution. The radiation patterns should ensure minimal interference with unwanted objects, usually present in the complex operational environment; to this aim, antennas should provide high directivity and concentrate the electromagnetic energy into a narrow solid angle. As GPR

  16. Stretchable and reversibly deformable radio frequency antennas based on silver nanowires.

    PubMed

    Song, Lingnan; Myers, Amanda C; Adams, Jacob J; Zhu, Yong

    2014-03-26

    We demonstrate a class of microstrip patch antennas that are stretchable, mechanically tunable, and reversibly deformable. The radiating element of the antenna consists of highly conductive and stretchable material with screen-printed silver nanowires embedded in the surface layer of an elastomeric substrate. A 3-GHz microstrip patch antenna and a 6-GHz 2-element patch array are fabricated. Radiating properties of the antennas are characterized under tensile strain and agree well with the simulation results. The antenna is reconfigurable because the resonant frequency is a function of the applied tensile strain. The antenna is thus well suited for applications like wireless strain sensing. The material and fabrication technique reported here could be extended to achieve other types of stretchable antennas with more complex patterns and multilayer structures. PMID:24593878

  17. Antennas for the array-based Deep Space Network: current status and future designs

    NASA Technical Reports Server (NTRS)

    Imbriale, William A.; Gama, Eric

    2005-01-01

    Development of very large arrays1,2 of small antennas has been proposed as a way to increase the downlink capability of the NASA Deep Space Network DSN) by two or three orders of magnitude thereby enabling greatly increased science data from currently configured missions or enabling new mission concepts. The current concept is for an array of 400 x 12-m antennas at each of three longitudes. The DSN array will utilize radio astronomy sources for phase calibration and will have wide bandwidth correlation processing for this purpose. NASA has undertaken a technology program to prove the performance and cost of a very large DSN array. Central to that program is a 3-element interferometer to be completed in 2005. This paper describes current status of the low cost 6-meter breadboard antenna to be used as part of the interferometer and the RF design of the 12-meter antenna.

  18. Feasibility study of a synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas

    NASA Technical Reports Server (NTRS)

    Stutzman, W. L.; Takamizawa, K.; Werntz, P.; Lapean, J.; Barts, R.; Shen, B.

    1992-01-01

    Virginia Tech has several articles which support the NASA Langley effort in the area of large aperture radiometric antenna systems. This semi-annual report reports on the following activities: a feasibility study of a synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas and the design of array feeds for large reflector antennas.

  19. Compensation of static deformation and vibrations of antenna arrays

    NASA Astrophysics Data System (ADS)

    Knott, Peter; Loecker, Claudius; Algermissen, Stephan; Sekora, Robert

    2012-11-01

    The effect of vibrations and static deformations on aerospace platforms and their influence on the performance of radar, navigation or communication systems are currently studied in the scope of the NATO Research Task Groups SET-131. The deformations may be caused by different effects, e.g. aerodynamic loads, vehicle motion, moving parts such as rudders or turbines, or the impact of a collision. Depending on their strength and the function of the wireless system, they may have a significant impact on the system performance. Structural aspects of the platform such as mechanical or thermal stability, aerodynamics or outer appearance are of great importance. The present paper gives an overview of the scope of work of the group and on-going investigations on system performance analysis and compensation methods such as adaptive signal processing or electronic phase compensation for military key applications such as RADAR, Communication, Electronic Support Measures (ESM) or Command and Control (C2). In addition, the development of an antenna array demonstrator with active vibration compensation using piezo sensors and actuators and control algorithms will be shown, including simulated as well as experimental results.

  20. Design Aspects of the Microstrip Reflectarray

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1998-01-01

    The microstrip reflectarray has been identified as one of the enabling technologies to achieve low mass, conformal mounting, wide-angle beam scanning, etc. for NASA's future speceborne high-gain antennas.