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1

A high speed image transmission system for ultra-wideband wireless links  

E-print Network

Ultra-wideband (UWB) communication is an emerging technology that offers short range, high data rate wireless transmission, with low power consumption and low consumer cost. Operating in the 3.1 GHz - 10.6 GHz frequency ...

Liang, Helen He

2009-01-01

2

Impact of Optical Transmission on Multiband OFDM Ultra-Wideband Wireless System With Fiber Distribution  

Microsoft Academic Search

Multiband (MB) orthogonal frequency-division multiplexing (OFDM) ultra-wideband (UWB) wireless, which provides high data rate access, is required to be distributed by using optical fiber. The performance of MB-OFDM UWB over fiber transmission system is investigated considering optical modulation and demodulation impact. Theoretical analysis of the effect of fiber dispersion, optical transmitter, and optical receiver response on system performance is carried

Meer Nazmus Sakib; Bouchaib Hraimel; Xiupu Zhang; Mohmoud Mohamed; Wei Jiang; Ke Wu; Dongya Shen

2009-01-01

3

Design of CMOS integrated frequency synthesizers for ultra-wideband wireless communications systems  

E-print Network

Ultra¬wide band (UWB) system is a breakthrough in wireless communication, as it provides data rate one order higher than existing ones. This dissertation focuses on the design of CMOS integrated frequency synthesizer and its building blocks used...

Tong, Haitao

2009-05-15

4

Pulse-based ultra-wideband transmitters for digital communication  

E-print Network

Ultra-wideband radio (UWB) is a rapidly developing wireless technology that promises unprecedented data rates for short-range commercial radios, combined with precise locationing and high energy efficiency. These benefits ...

Wentzloff, David D. (David Dale), 1977-

2007-01-01

5

A framework for cooperative localization in ultra-wideband wireless networks  

E-print Network

Location-aware technologies have the potential to revolutionize computing, cellular services, sensor networks, and many other commercial, military, and social applications. In wireless networks, accurate information about ...

Lien, Jaime

2007-01-01

6

Self organization of wireless sensor networks using ultra-wideband radios  

DOEpatents

A novel UWB communications method and system that provides self-organization for wireless sensor networks is introduced. The self-organization is in terms of scalability, power conservation, channel estimation, and node synchronization in wireless sensor networks. The UWB receiver in the present invention adds two new tasks to conventional TR receivers. The two additional units are SNR enhancing unit and timing acquisition and tracking unit.

Dowla, Farid U. (Castro Valley, CA); Nekoogar, Franak (San Ramon, CA); Spiridon, Alex (Palo Alto, CA)

2009-06-16

7

Ultra wideband surface wave communications  

NASA Astrophysics Data System (ADS)

Ultra Wideband (UWB), an impulse carrier waveform, was applied at HF-VHF frequencies to utilize surface wave propagation. UWB involves the propagation of transient pulses rather than continuous waves which makes the system easier to implement, inexpensive, low power and small. Commercial UWB for wireless personal area networks is 3.1 to 10.6 GHz band as approved by the FCC with ranges up to 12 ft. The use of surface wave propagation (instead of commercial SHF UWB) extends the communication range. Surface wave is a means of propagation where the wave is guided by the surface of the Earth. Surface wave is efficient at low frequencies, VLF to HF. The UWB HF channel was modeled and also experimentally characterized. The Federal Communications Commission (FCC) defines UWB as a signal with either a fractional bandwidth of 20% of the center frequency or a bandwidth of 500MHz. Designing an antenna to operate over the 20% bandwidth requirement of UWB is one of the greatest challenges. Two different antenna designs are presented, a spoke top antenna and a traveling wave antenna with photonic bandgap. These designs were implemented at the commercial UWB frequencies (3.1--10.6 GHz) due to availability of modeling tools for the higher frequencies, the reduced antenna size and the availability of measurement facilities. The spoke top was optimum for replication of the time domain input signal. The traveling wave antenna with photonic bandgap demonstrated increased impedance bandwidth of the antenna.

Lacomb, Julie Anne

8

Ultra-wideband digital baseband  

E-print Network

The FCC approved the use of Ultra-wideband signals for communication purposes in February 2002 in the band from 3.1GHz to 10.6GHz, effectively opening 7.5GHz of free unlicensed bandwidth. There are two main constraints for ...

Blázquez-Fernández, Raúl, 1975-

2006-01-01

9

An 8GHz Ultra Wideband Transceiver Prototyping Testbed  

Microsoft Academic Search

Software defined radios have the potential of changing the fundamental usage model of wireless communications devices, but the capabilities of these transceivers are often limited by the speed of the underlying processors and FPGAs. This paper presents a testbed for the design of an impulse-based ultra wideband communication system. The transceiver is being developed using software\\/reconfigurable radio concepts and will

Deepak Argarwal; Christopher R. Anderson; Peter M. Athanas

2005-01-01

10

Wideband local access: wireless LAN and wireless ATM  

Microsoft Academic Search

An overview of the status of wideband wireless local access technologies is provided. Service scenarios and availability of the market and products for wireless LAN and wireless ATM technologies are discussed. Similarities among IEEE 802.11 and HIPERLAN standards for wireless LANs and the developing prototypes for wireless ATM are evaluated. An update on the status of the available unlicensed bands

K. Pahlavan; A. Zahedi; P. Krishnamurthy

1997-01-01

11

Ultra-wideband directional sampler  

DOEpatents

The Ultra-Wideband (UWB) Directional Sampler is a four port device that combines the function of a directional coupler with a high speed sampler. Two of the four ports operate at a high sub-nanosecond speed, in ``real time``, and the other two ports operate at a slow millisecond-speed, in ``equivalent time``. A signal flowing inbound to either of the high speed ports is sampled and coupled, in equivalent time, to the adjacent equivalent time port while being isolated from the opposite equivalent time port. A primary application is for a time domain reflectometry (TDR) situation where the reflected pulse returns while the outbound pulse is still being transmitted, such as when the reflecting discontinuity is very close to the TDR apparatus. 3 figs.

McEwan, T.E.

1996-05-14

12

Ultra-wideband directional sampler  

DOEpatents

The Ultra-Wideband (UWB) Directional Sampler is a four port device that combines the function of a directional coupler with a high speed sampler. Two of the four ports operate at a high sub-nanosecond speed, in "real time", and the other two ports operate at a slow millisecond-speed, in "equivalent time". A signal flowing inbound to either of the high speed ports is sampled and coupled, in equivalent time, to the adjacent equivalent time port while being isolated from the opposite equivalent time port. A primary application is for a time domain reflectometry (TDR) situation where the reflected pulse returns while the outbound pulse is still being transmitted, such as when the reflecting discontinuity is very close to the TDR apparatus.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

13

Antenna design for ultra wideband radio  

E-print Network

The recent allocation of the 3.1-10.6 GHz spectrum by the Federal Communications Commission (FCC) for Ultra Wideband (UWB) radio applications has presented a myriad of exciting opportunities and challenges for design in ...

Powell, Johnna, 1980-

2004-01-01

14

Ultra-Wideband Microwave Imaging of Heterogeneities  

E-print Network

-time imaging, ground penetrating radar, ultra-wideband imaging, migration Corresponding Author: Department and the other is the employment of ground penetrating radar (GPR) for imaging the near surface of the earth

Boyer, Edmond

15

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 54, NO. 5, SEPTEMBER 2005 1623 An Ultra-Wideband Transceiver Architecture for Low  

E-print Network

Terms--Digital radio, impulse radio, low power, transceiver, ultra-wideband. I. INTRODUCTION approaches due to the wideband, i.e., low-Q, nature of the radio. The anticipated power savings, over-Wideband Transceiver Architecture for Low Power, Low Rate, Wireless Systems Ian D. O'Donnell, Member, IEEE, and Robert

Southern California, University of

16

Ultra Wideband InterferenceUltra Wideband Interference Effects on an AmateurEffects on an Amateur  

E-print Network

Ultra Wideband InterferenceUltra Wideband Interference Effects on an AmateurEffects on an AmateurSensitivity is important 1. http://www.arrl.org #12;Amateur Radio BandsAmateur Radio Bands MHz GHz Mid-Range Imaging Indoor · Compressed output level depends on clipping level and duty cycle · 5dB differential implies UWB signal has 30

Southern California, University of

17

Ultra-wideband impedance sensor  

DOEpatents

The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. One broad application area is the general replacement of magnetic sensors, particularly where nonferrous materials need to be sensed. Another broad application area is sensing full/empty levels in tanks, vats and silos, e.g., a full/empty switch in water or petroleum tanks. 2 figs.

McEwan, T.E.

1999-03-16

18

Ultra-wideband impedance sensor  

DOEpatents

The ultra-wideband impedance sensor (UWBZ sensor, or Z-sensor) is implemented in differential and single-ended configurations. The differential UWBZ sensor employs a sub-nanosecond impulse to determine the balance of an impedance bridge. The bridge is configured as a differential sample-and-hold circuit that has a reference impedance side and an unknown impedance side. The unknown impedance side includes a short transmission line whose impedance is a function of the near proximity of objects. The single-ended UWBZ sensor eliminates the reference side of the bridge and is formed of a sample and hold circuit having a transmission line whose impedance is a function of the near proximity of objects. The sensing range of the transmission line is bounded by the two-way travel time of the impulse, thereby eliminating spurious Doppler modes from large distant objects that would occur in a microwave CW impedance bridge. Thus, the UWBZ sensor is a range-gated proximity sensor. The Z-sensor senses the near proximity of various materials such as metal, plastic, wood, petroleum products, and living tissue. It is much like a capacitance sensor, yet it is impervious to moisture. One broad application area is the general replacement of magnetic sensors, particularly where nonferrous materials need to be sensed. Another broad application area is sensing full/empty levels in tanks, vats and silos, e.g., a full/empty switch in water or petroleum tanks.

McEwan, Thomas E. (Livermore, CA)

1999-01-01

19

Digital ADCs and ultra-wideband RF circuits for energy constrained wireless applications by Denis Clarke Daly.  

E-print Network

Ongoing advances in semiconductor technology have enabled a multitude of portable, low power devices like cellular phones and wireless sensors. Most recently, as transistor device geometries reach the nanometer scale, ...

Daly, Denis Clarke

2009-01-01

20

Microwave and millimeter-wave rectifying circuit arrays and ultra-wideband antennas for wireless power transmission and communications  

E-print Network

In the future, space solar power transmission and wireless power transmission will play an important role in gathering clean and infinite energy from space. The rectenna, i.e., a rectifying circuit combined with an antenna, is one of the most...

Ren, Yu-Jiun

2009-05-15

21

Ultra Wideband Electromagnetic Phantoms for Antennas and Propagation Studies  

NASA Astrophysics Data System (ADS)

Ultra wideband (UWB) technologies are expected to be used in ultra-high-speed wireless personal area networks (WPAN) and wireless body area networks (WBAN). UWB human electromagnetic phantoms are useful for performance evaluation of antennas mounted in the vicinity of a human body and channel assessment when a human body blocks a propagation path. Publications on UWB phantoms, however, have been limited so far. This paper describes the development of liquid UWB phantom material (aqueous solution of sucrose) and UWB arm and torso phantoms. The UWB phantoms are not intended to evaluate a specific absorption rate (SAR) in a human body, because UWB devices are supposed to transmit at very low power and thus should pose no human hazard.

Yamamoto, Hironobu; Zhou, Jian; Kobayashi, Takehiko

22

Ultra-wideband radar motion sensor  

DOEpatents

A motion sensor is based on ultra-wideband (UWB) radar. UWB radar range is determined by a pulse-echo interval. For motion detection, the sensors operate by staring at a fixed range and then sensing any change in the averaged radar reflectivity at that range. A sampling gate is opened at a fixed delay after the emission of a transmit pulse. The resultant sampling gate output is averaged over repeated pulses. Changes in the averaged sampling gate output represent changes in the radar reflectivity at a particular range, and thus motion. 15 figs.

McEwan, T.E.

1994-11-01

23

Ultra-wideband radar motion sensor  

DOEpatents

A motion sensor is based on ultra-wideband (UWB) radar. UWB radar range is determined by a pulse-echo interval. For motion detection, the sensors operate by staring at a fixed range and then sensing any change in the averaged radar reflectivity at that range. A sampling gate is opened at a fixed delay after the emission of a transmit pulse. The resultant sampling gate output is averaged over repeated pulses. Changes in the averaged sampling gate output represent changes in the radar reflectivity at a particular range, and thus motion.

McEwan, Thomas E. (Livermore, CA)

1994-01-01

24

Ultra-Wideband OFDM Radar and Communication System.  

E-print Network

??This paper examines the possibility of a dual use radar and communication systembased on ultra-wideband orthogonal frequency division multiplexed (OFDM)waveforms. Theory for utilizing OFDM as… (more)

Schuerger, Jonathan Paul

2009-01-01

25

Software-Defined Ultra-wideband Radio Communications: A New RF Technology for Emergency Response Applications  

SciTech Connect

Reliable wireless communication links for local-area (short-range) and regional (long-range) reach capabilities are crucial for emergency response to disasters. Lack of a dependable communication system can result in disruptions in the situational awareness between the local responders in the field and the emergency command and control centers. To date, all wireless communications systems such as cell phones and walkie-talkies use narrowband radio frequency (RF) signaling for data communication. However, the hostile radio propagation environment caused by collapsed structures and rubble in various disaster sites results in significant degradation and attenuation of narrowband RF signals, which ends up in frequent communication breakdowns. To address the challenges of reliable radio communication in disaster fields, we propose an approach to use ultra-wideband (UWB) or wideband RF waveforms for implementation on Software Defined Radio (SDR) platforms. Ultra-wideband communications has been proven by many research groups to be effective in addressing many of the limitations faced by conventional narrowband radio technologies. In addition, LLNL's radio and wireless team have shown significant success in field deployment of various UWB communications system for harsh environments based on LLNL's patented UWB modulation and equalization techniques. Furthermore, using software defined radio platform for UWB communications offers a great deal of flexibility in operational parameters and helps the radio system to dynamically adapt itself to its environment for optimal performance.

Nekoogar, F; Dowla, F

2009-10-19

26

Waveform Optimizations for Ultra-Wideband Radio Systems  

Microsoft Academic Search

Solutions are presented for various optimizations of transient waveforms and signals used in ultra-wideband radio systems. These include the transmit antenna generator waveform required to maximize receive antenna voltage amplitude (with bounded input energy), the transmit antenna generator waveform that provides the \\

David M. Pozar

27

Commercialization of an ultra wideband precision asset location system  

Microsoft Academic Search

Ultra wideband (UWB) technology has been shown to possess unique advantages for precision localization applications. The use of short pulse RF waveforms provides inherent precision for time difference of arrival measurements, as well immunity to multipath effects in indoor applications. This paper describes an FCC-approved, commercial UWB precision asset location system which is being used for tracking of high valued

Robert J. Fontana; Edward Richley; JoAnn Barney

2003-01-01

28

Compact frequency notched ultra-wideband fractal printed slot antenna  

Microsoft Academic Search

A novel frequency notched ultra-wideband (UWB) fractal printed slot antenna is proposed. The antenna is similar in configuration to a conventional microstrip-fed wide slot antenna, however, by introducing a Koch fractal slot, not only the size of the antenna is reduced significantly but also frequency notched function is achieved. Several properties of the antenna such as impedance bandwidth, frequency notched

W. J. Lui; C. H. Cheng; H. B. Zhu

2006-01-01

29

Wireless wideband SAW sensor - antenna design  

Microsoft Academic Search

Wireless SAW RFID sensors offer several advantages over similar silicon technology that include passive operation, radiation hardness, and the ability to operate in extreme temperatures. Due to these unique material and device properties, NASA has shown considerable interest in passive, wireless SAW sensors for ground and space flight operations. Several embodiments of SAW sensors have been well established in literature,

M. W. Gallagher; B. C. Santos; D. C. Malocha

2010-01-01

30

An Overview of the Recent Wideband Transcutaneous Wireless Communication Techniques  

PubMed Central

Neuroprosthetic devices such as cochlear and retinal implants need to deliver a large volume of data from external sensors into the body, while invasive brain-computer interfaces need to deliver sizeable amounts of data from the central nervous system to target devices outside of the body. Nonetheless, the skin should remain intact. This paper reviews some of the latest techniques to establish wideband wireless communication links across the skin. PMID:22255673

Ghovanloo, Maysam

2013-01-01

31

Space-time coded OFDM for high data-rate wireless communication over wideband channels  

Microsoft Academic Search

There has been an increasing interest in providing high data-rate services such as video-conferencing, multimedia Internet access and wide area network over wideband wireless channels. Wideband wireless channels available in the PCS band (2 GHz) have been envisioned to be used by mobile (high Doppler) and stationary (low Doppler) units in a variety of delay spread profiles. This is a

Dakshi Agrawall; Vahid Tarokh; Ayman Naguib; Nambi Seshadri

1998-01-01

32

High-rate transmission scheme for pulse-based ultra-wideband systems over dense multipath  

E-print Network

High-rate transmission scheme for pulse-based ultra-wideband systems over dense multipath indoor-forcing (ZF), and a high-performance ZF-based successive receiver for effective detection in the presence-based ultra-wideband (UWB) systems [1­10] transmits one short- duration, low-duty-cycle pulse every pulse

Liu, Huaping

33

Design of a CPW-fed Ultra Wideband Crown Circular Fractal Antenna  

Microsoft Academic Search

A new ultra wideband antenna fed by coplanar waveguide (CPW) is presented in this paper. A fractal structure is constructed to obtain ultra wideband (UWB) performance. The parameters and characteristics of the antenna and the simulation results show that the 6:1 or more bandwidth is achieved with the second order iterative antenna structure

Min Ding; Ronghong Jin; Junping Geng; Qi Wu; Wei Wang

2006-01-01

34

A new ultra-wideband, ultra-short monocycle pulse generator with reduced ringing  

Microsoft Academic Search

We introduce a new ultra-wideband (UWB), ultra-short, step recovery diode monocycle pulse generator. This pulse generator uses a simple RC high-pass filter as a differentiator to generate the monocycle pulse directly. The pulse-shaping network employs a resistive circuit to achieve UWB matching and substantial removal of the pulse ringing, and rectifying and switching diodes to further suppress the ringing. An

Jeongwoo Han; Cam Nguyen

2002-01-01

35

Survey of Ultra-wideband Radar  

NASA Astrophysics Data System (ADS)

The development of UWB radar over the last four decades is very briefly summarized. A discussion of the meaning of UWB is followed by a short history of UWB radar developments and discussions of key supporting technologies and current UWB radars. Selected UWB radars and the associated applications are highlighted. Applications include detecting and imaging buried mines, detecting and mapping underground utilities, detecting and imaging objects obscured by foliage, through-wall detection in urban areas, short-range detection of suicide bombs, and the characterization of the impulse responses of various artificial and naturally occurring scattering objects. In particular, the Naval Research Laboratory's experimental, low-power, dual-polarized, short-pulse, ultra-high resolution radar is used to discuss applications and issues of UWB radar. Some crucial issues that are problematic to UWB radar are spectral availability, electromagnetic interference and compatibility, difficulties with waveform control/shaping, hardware limitations in the transmission chain, and the unreliability of high-power sources for sustained use above 2 GHz.

Mokole, Eric L.; Hansen, Pete

36

An adaptive Orthogonaly Division Multiplexing baseband modem for wideband wireless communication  

E-print Network

This thesis shows the design of an Orthogonal Frequency Division Multiplexing base-band modem with Frequency Adaptive Modulation protocol for a wideband indoor wireless channel. The baseband modem is implemented on a Field ...

Tan, Jit Ken

2006-01-01

37

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC  

E-print Network

matching using active negative inductance elements · Modeling of multipath propagation Dave Pozar #12;Short of radius a mathematical sphere of radius a Dave Pozar #12;Short-Range Ultra-Wideband Systems UMass Antenna

Southern California, University of

38

Ultra-wideband optical leaky-wave slot antennas.  

PubMed

We propose and investigate an ultra-wideband leaky-wave antenna that operates at optical frequencies for the purpose of efficient energy coupling between localized nanoscale optical circuits and the far-field. The antenna consists of an optically narrow aluminum slot on a silicon substrate. We analyze its far-field radiation pattern in the spectral region centered around 1550 nm with a 50% bandwidth ranging from 2000 nm to 1200 nm. This plasmonic leaky-wave slot produces a maximum far-field radiation angle at 32° and a 3 dB beamwidth of 24° at its center wavelength. The radiation pattern is preserved within the 50% bandwidth suffering only insignificant changes in both the radiation angle and the beamwidth. This wide-band performance is quite unique when compared to other optical antenna designs. Furthermore, the antenna effective length for radiating 90% and 99.9% of the input power is only 0.5?(0) and 1.5?(0) respectively at 1550 nm. The versatility and simplicity of the proposed design along with its small footprint makes it extremely attractive for integration with nano-optical components using existing technologies. PMID:21716477

Wang, Yan; Helmy, Amr S; Eleftheriades, George V

2011-06-20

39

Ultra wideband digital to analog conversion based on advanced InP DHBT technology  

Microsoft Academic Search

Wideband digital-to-analog converters (DACs) are key to future high performance military electronic systems. This paper presents the results of an ultra wideband DAC based on advanced InP DHBT technology. The chip integrates a 40-to-10 bit digital multiplexer with a 10-bit DAC and associated clock generation.

D. Ching; K. Tsai; A. Gutierrez; B. Oyama

2005-01-01

40

Ultra-wideband Location Authentication for Item Tracking  

SciTech Connect

International safeguards is increasingly utilizing unattended and remote monitoring methods to improve inspector efficiency and the timeliness of diversion detection. Item identification and tracking has been proposed as one unattended remote monitoring method, and a number of radio-frequency (RF) technologies have been proposed. When utilizing location information for verification purposes, strong assurance of the authenticity of the reported location is required, but most commercial RF systems are vulnerable to a variety of spoofing and relay attacks. ORNL has developed a distance bounding method that uses ultra-wideband technology to provide strong assurance of item location. This distance bounding approach can be coupled with strong symmetric key authentication methods to provide a fully authenticable tracking system that is resistant to both spoofing and relay attacks. This paper will discuss the overall problems associated with RF tracking including the common spoofing and relay attack scenarios, the ORNL distance bounding approach for authenticating location, and the potential applications for this technology.

Rowe, Nathan C [ORNL; Kuhn, Michael J [ORNL; Stinson, Brad J [ORNL; Holland, Stephen A [ORNL

2012-01-01

41

An ultra-wideband surface plasmonic filter in microwave frequency  

NASA Astrophysics Data System (ADS)

We propose an ultra-wideband plasmonic waveguide based on designer surface plasmon polaritons (DSPPs) with double gratings. In such plasmonic metamaterials, the DSPP waves in the region of lower frequencies of the dispersion curve can be tightly confined and hence effectively broaden the operating bandwidth. Based on such features, we design and fabricate a high performance DSPP filter, in which a transducer consisting of microstrip, slotline, and gradient corrugations is employed to feed electromagnetic energies into the plasmonic waveguide with high efficiency. The simulated and measured results on reflection and transmission coefficients in the microwave frequency demonstrate the excellent filtering characteristics such as low loss, wide band, and high square ratio. The high performance DSPP waveguide and filter pave a way to develop advanced plasmonic integrated functional devices and circuits in the microwave and terahertz frequencies.

Gao, Xi; Zhou, Liang; Liao, Zhen; Ma, Hui Feng; Cui, Tie Jun

2014-05-01

42

Micro-Doppler processing for ultra-wideband radar data  

NASA Astrophysics Data System (ADS)

In this paper, we describe an operational pulse Doppler radar imaging system for indoor target localization and classification, and show how a target's micro-Doppler signature (?DS) can be processed when ultra-wideband (UWB) waveforms are employed. Unlike narrowband radars where time-frequency signal representations can be applied to reveal the target time-Doppler frequency signatures, the UWB system permits joint range-time-frequency representation (JRTFR). JRTFR outputs the data in a 3D domain representing range, frequency, and time, allowing both the ?DS and high range resolution (HRR) signatures to be observed. We delineate the relationship between the ?DS and the HRR signature, showing how they would form a complimentary joint feature for classification. We use real-data to demonstrate the effectiveness of the UWB pulse-Doppler radar, combined with nonstationary signal analyses, in gaining valuable insights into human positioning and motions.

Smith, Graeme E.; Ahmad, Fauzia; Amin, Moeness G.

2012-06-01

43

Generalized equivalent circuit model for ultra wideband antenna structure with double steps for energy scavenging  

NASA Astrophysics Data System (ADS)

There are various types of UWB antennas can be used to scavenge energy from the air and one of them is the printed disc monopole antenna. One of the new challenges imposed on ultra wideband is the design of a generalized antenna circuit model. It is developed in order to extract the inductance and capacitance values of the UWB antennas. In this research work, the developed circuit model can be used to represent the rectangular printed disc monopole antenna with double steps. The antenna structure is simulated with CST Microwave Studio, while the circuit model is simulated with AWR Microwave Office. In order to ensure the simulation result from the circuit model is accurate, the circuit model is also simulated using Mathlab program. The developed circuit model is found to be able to depict the actual UWB antenna. Energy harvesting from environmental wirelessly is an emerging method, which forms a promising alternative to existing energy scavenging system. The developed UWB can be used to scavenge wideband energy from electromagnetic wave present in the environment.

>Oon Kheng Heong, Goh Chin; Chakrabarty, Chandan Kumar; >Goh Tian Hock,

2013-06-01

44

Ground Reflection Path Loss Based on Average Power Loss for Ultra Wideband Communications  

Microsoft Academic Search

In this paper, the ground reflection path loss based on average power loss for ultra wideband (UWB) communications is proposed. The expression is derived from the rectangular passband waveform and extension of Friis\\

Pichaya Supanakoon; Sarunya Kaewsirisin; Sathaporn Promwong; Suthichai Noppanakeepong; Jun-ichi Takada

2007-01-01

45

Robust range-based localization and motion planning under uncertainty using ultra-wideband radio  

E-print Network

The work presented in this thesis addresses two problems: accurately localizing a mobile robot using ultra-wideband (UWB) radio signals in GPS-denied environments; and planning robot trajectories that incorporate belief ...

Prentice, Samuel J. (Samuel James)

2007-01-01

46

Development of an electronically tunable ultra-wideband radar imaging sensor and its components  

E-print Network

Novel microwave transmitter and receiver circuits have been developed for implementing UWB (Ultra-Wideband) impulse radar imaging sensor operating in frequency band 0.2 to 4 GHz. with tunable operating frequency band. The fundamental system design...

Han, Jeongwoo

2006-08-16

47

Reconfigurable Wideband Circularly Polarized Microstrip Patch Antenna for Wireless Applications  

NASA Astrophysics Data System (ADS)

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 vice versa, with the aid of two RF PIN diodes that act as RF switches. The proposed structure which is simple; consists of a single-layer single fed radiating E-shaped patch and RF switch placed on each of its slots at an appropriate location. The design targets WLAN IEEE 802.11b/g frequency band (2.4- 2.5 GHz) as one example of the wireless applications. The idea is based on the first proposed design. In other words, if one of the switches is ON and the other is OFF, the two slot lengths will become effectively unequal and circular polarization will be obtained. If the states of the two switches are reversed, circular polarization with opposite orientation will be obtained at the same frequency band. Full-wave simulator Ansoft HFSS is again used for the analysis. Complete detailed DC biasing circuit of the switches for integration with the antenna is presented. Also, characterizations of the microwave components used in the biasing circuit are discussed. Antenna prototype has been fabricated and tested. Simulation results along with the measured one, for the reflection coefficient, axial ratio, radiation pattern, and antenna gain agree well, showing wide bandwidth and high gain for the two circularly polarized modes.

Khidre, Ahmed

48

Analysis and Design of Two Low-Power Ultra-Wideband CMOS Low-Noise Amplifiers With Out-Band Rejection  

Microsoft Academic Search

Two 3-5-GHz low-power ultra-wideband (UWB) low-noise amplifiers (LNAs) with out-band rejection function using 0.18- ??m CMOS technology are presented. Due to the Federal Communications Commission's stringent power-emission limitation at the transmitter, the received signal power in the UWB system is smaller than those of the close narrowband interferers such as the IEEE 802.11 a\\/b\\/g wireless local area network, and the

Ching-Piao Liang; Pei-Zong Rao; Tian-Jian Huang; Shyh-Jong Chung

2010-01-01

49

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC  

E-print Network

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC MURI Review Research Effort -- Bob Scholtz 9:20 AM: Algorithm and System Architecture Studies Panel: Keith Chugg, Capacity Limits of UWB Impulse Radios 10:35 AM: Break 10:45 AM: Antennas and Propagation Topics: Simulation

Southern California, University of

50

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC  

E-print Network

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC 1:15 PM: Circuit Design Panel: Bob Brodersen, Won Namgoong, Mike Chen, Ian O'Donnell, Stanley Wang Topics: UWB Low channel, UWB Performance and CMOS Impairments, Complete Asset Tracking System Panel: The UWB MURI Team 3

Southern California, University of

51

Wideband Dynamic Radio Spectra of Two Ultra-cool dwarfs  

E-print Network

A number of radio-loud ultra cool dwarf (UCD) stars exhibit both continuous broadband and highly polarized pulsed radio emission. In order to determine the nature of the emission and the physical characteristics in the source region, we have made multi-epoch, wideband spectral observations of two UCD stars, TVLM 0513-46 and 2M 0746+20. We combine these observations with previously published and archival radio data to fully characterize both the temporal and spectral properties of the radio emission. The continuum spectral energy distribution and fractional polarization can be well modeled using gyrosynchrotron emission with mean magnetic field $B\\sim10-70$ G, mildly relativistic power-law electrons of number density $n_e\\sim10^{5-6}$cm$^{-3}$, and source size $R\\sim 2R_s$. The pulsed emission exhibits a variety of time-variable characteristics, including large frequency drifts, high and low frequency cutoffs, and multiple pulses per period. For 2M 0746+20 we determine a main pulse period consistent with previ...

Lynch, C; Gudel, M

2014-01-01

52

Ultra-Wideband Tracking System Design for Relative Navigation  

NASA Technical Reports Server (NTRS)

This presentation briefly discusses a design effort for a prototype ultra-wideband (UWB) time-difference-of-arrival (TDOA) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being designed for use in localization and navigation of a rover in a GPS deprived environment for surface missions. In one application enabled by the UWB tracking, a robotic vehicle carrying equipments can autonomously follow a crewed rover from work site to work site such that resources can be carried from one landing mission to the next thereby saving up-mass. The UWB Systems Group at JSC has developed a UWB TDOA High Resolution Proximity Tracking System which can achieve sub-inch tracking accuracy of a target within the radius of the tracking baseline [1]. By extending the tracking capability beyond the radius of the tracking baseline, a tracking system is being designed to enable relative navigation between two vehicles for surface missions. A prototype UWB TDOA tracking system has been designed, implemented, tested, and proven feasible for relative navigation of robotic vehicles. Future work includes testing the system with the application code to increase the tracking update rate and evaluating the linear tracking baseline to improve the flexibility of antenna mounting on the following vehicle.

Ni, Jianjun David; Arndt, Dickey; Bgo, Phong; Dekome, Kent; Dusl, John

2011-01-01

53

Optimal waveforms design for ultra-wideband impulse radio sensors.  

PubMed

Ultra-wideband impulse radio (UWB-IR) sensors should comply entirely with the regulatory spectral limits for elegant coexistence. Under this premise, it is desirable for UWB pulses to improve frequency utilization to guarantee the transmission reliability. Meanwhile, orthogonal waveform division multiple-access (WDMA) is significant to mitigate mutual interferences in UWB sensor networks. Motivated by the considerations, we suggest in this paper a low complexity pulse forming technique, and its efficient implementation on DSP is investigated. The UWB pulse is derived preliminarily with the objective of minimizing the mean square error (MSE) between designed power spectrum density (PSD) and the emission mask. Subsequently, this pulse is iteratively modified until its PSD completely conforms to spectral constraints. The orthogonal restriction is then analyzed and different algorithms have been presented. Simulation demonstrates that our technique can produce UWB waveforms with frequency utilization far surpassing the other existing signals under arbitrary spectral mask conditions. Compared to other orthogonality design schemes, the designed pulses can maintain mutual orthogonality without any penalty on frequency utilization, and hence, are much superior in a WDMA network, especially with synchronization deviations. PMID:22163511

Li, Bin; Zhou, Zheng; Zou, Weixia; Li, Dejian; Zhao, Chong

2010-01-01

54

Ultra-wideband radios for time-of-flight-ranging and network position estimation  

Microsoft Academic Search

This invention provides a novel high-accuracy indoor ranging device that uses ultra-wideband (UWB) RF pulsing with low-power and low-cost electronics. A unique of the present invention is that it exploits multiple measurements in time and space for very accurate ranging. The wideband radio signals utilized herein are particularly suited to ranging in harsh RF environments because they allow signal reconstruction

Claudia A. Hertzog; Farid U. Dowla; Gregory E. Dallum; Carlos E. Romero

2011-01-01

55

An ultra-wideband CMOS low noise amplifier for 3-5GHz UWB system  

Microsoft Academic Search

Abstract—An ultra-wideband (UWB) CMOS low noise amplifier (LNA) topology that combines a narrowband LNA with a resistive shunt-feedback is proposed. The resistive shunt-feedback provides wideband input matching with small noise figure (NF) degradation by reducing the Q-factor of the narrowband LNA input and flattens the passband gain. The proposed UWB amplifier is implemented in 0.18- m CMOS technology for a

Chang-Wan Kim; Min-Suk Kang; Phan Tuan Anh; Hoon-Tae Kim; Sang-Gug Lee

2005-01-01

56

Optical correlation of ultra-wideband signals using time-space-conversion C. Seifarth, H. Knuppertz, J. Jahns  

E-print Network

Optical correlation of ultra-wideband signals using time-space-conversion C. Seifarth, H. Knuppertz acoustic waves and deflect it at different angles depending on the temporal spectral components of the input signal. Ultra-wideband (UWB) devices as defined by the European Commission spread their RF energy

Jahns, Jürgen

57

Augmented reality using ultra-wideband radar imagery  

NASA Astrophysics Data System (ADS)

The U.S. Army Research Laboratory (ARL) has been investigating the utility of ultra-wideband (UWB) synthetic aperture radar (SAR) technology for detecting concealed targets in various applications. We have designed and built a vehicle-based, low-frequency UWB SAR radar for proof-of-concept demonstration in detecting obstacles for autonomous navigation, detecting concealed targets (mines, etc.), and mapping internal building structures to locate enemy activity. Although the low-frequency UWB radar technology offers valuable information to complement other technologies due to its penetration capability, it is very difficult to comprehend the radar imagery and correlate the detection list from the radar with the objects in the real world. Using augmented reality (AR) technology, we can superimpose the information from the radar onto the video image of the real world in real-time. Using this, Soldiers would view the environment and the superimposed graphics (SAR imagery, detection locations, digital map, etc.) via a standard display or a head-mounted display. The superimposed information would be constantly changed and adjusted for every perspective and movement of the user. ARL has been collaborating with ITT Industries to implement an AR system that integrates the video data captured from the real world and the information from the UWB radar. ARL conducted an experiment and demonstrated the real-time geo-registration of the two independent data streams. The integration of the AR sub-system into the radar system is underway. This paper presents the integration of the AR and SAR systems. It shows results that include the real-time embedding of the SAR imagery and other information into the video data stream.

Nguyen, Lam; Koenig, Francois; Sherbondy, Kelly

2011-06-01

58

A low power, high dynamic-range, broadband variable gain amplifier for an ultra wideband receiver  

E-print Network

is designed for high frequency and low power communication applications, such as an Ultra Wideband (UWB) receiver system. The gain can be programmed from 0dB to 42dB in 2dB increments with -3dB bandwidth greater than 425MHz for the entire range of gain. The 3...

Chen, Lin

2007-09-17

59

Fingerprinting Localization based on Neural Networks and Ultra-wideband signals  

E-print Network

Fingerprinting Localization based on Neural Networks and Ultra-wideband signals Lei Yu, Mohamed Abstract--Fingerprinting techniques have been proved as an effective techniques for determining (RSS) are subject to big positioning errors. In this paper, a fingerprinting based localization

Paris-Sud XI, Université de

60

A computational study of ultra-wideband versus narrowband microwave hyperthermia for breast cancer treatment  

Microsoft Academic Search

We present a computational study comparing the performance of narrowband (NB) microwave hyperthermia for breast cancer treatment with a recently proposed ultra-wideband (UWB) approach. Space-time beamforming is used to preprocess input signals from both UWB and NB sources. The train of UWB pulses or the NB sinusoidal signals are then transmitted simultaneously from multiple antennas into the breast. Performance is

Mark Converse; Essex J. Bond; Barry D. Van Veen; C. Hagness

2006-01-01

61

ORAL PRESENTATION ABSTRACT Antenna Array Design for Ultra-wideband Microwave Detection of Breast Cancer Tumours  

E-print Network

ORAL PRESENTATION ABSTRACT Antenna Array Design for Ultra-wideband Microwave Detection of Breast Cancer Tumours by Alistair Johnson Electrical and Biomedical Engineering It has been reported in literature that cancerous tissue in the breast exhibits separate dielectric properties than normal breast

Haykin, Simon

62

Regression models of ultra wideband ground reflection path loss based on peak power loss  

Microsoft Academic Search

In this paper, the regression models of ultra wideband (UWB) ground reflection path loss are proposed. The UWB ground reflection path loss is defined as the ratio between the maximum amplitude of the transmitted and received signal waveforms. The polarizations of transmitted signal and ground characteristics are considered. The double and triple linear regression models are derived from the closed

Pichaya Supanakoon; Apiradee Pokang; Sathaporn Promwong; Suthichai Noppanakeepong; Jun-ichi Takada

2007-01-01

63

Pulsed frequency modulation techniques for high-precision ultra wideband ranging and positioning  

Microsoft Academic Search

In this paper a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. The system combines the advantages of FMCW radar systems and the

Benjamin Waldmann; Robert Weigel; Peter Gulden; Martin Vossiek

2008-01-01

64

Method for high precision local positioning radar using an ultra wideband technique  

Microsoft Academic Search

In this paper, a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. With this concept, a high accuracy in dense multipath indoor environments

Benjamin Waldmann; Robert Weigel; Peter Gulden

2008-01-01

65

CPW-Fed Quasi-Magnetic Printed Antenna for Ultra-Wideband Applications  

Microsoft Academic Search

An optimized coplanar waveguide fed quasimagnetic printed antenna for ultra wideband applications is described. A parameter study, motivated by a design procedure, allowed a substantial increase in the return-loss operational bandwidth. The numerically predicted performance was validated by means of physical measurements of fabricated samples. The measured radiation patterns of the antenna demonstrated its adequate radiation characteristics. The feed radiation

F. Muge Tanyer-Tigrek; Dani P. Tran; I. E. Lager; Leonardus P. Ligthart

2009-01-01

66

Optimal Resource Management in Wireless Multimedia Wideband CDMA Systems  

Microsoft Academic Search

Abstract - This paper proposes a scheme of optimal resource management for reverse - link transmissions in multimedia wideband code - division multiple - access (WCDMA) communications It is to guarantee quality - of - service (QoS) by resource (transmit power and rate) allocation and to achieve high spectral efficiency by base - station assignment This approach takes the form

Majid Soleimanipour; Weihua Zhuang; George H. Freeman

2002-01-01

67

Design and Performance Evaluation on Ultra-Wideband Time-Of-Arrival 3D Tracking System  

NASA Technical Reports Server (NTRS)

A three-dimensional (3D) Ultra-Wideband (UWB) Time--of-Arrival (TOA) tracking system has been studied at NASA Johnson Space Center (JSC) to provide the tracking capability inside the International Space Station (ISS) modules for various applications. One of applications is to locate and report the location where crew experienced possible high level of carbon-dioxide and felt upset. In order to accurately locate those places in a multipath intensive environment like ISS modules, it requires a robust real-time location system (RTLS) which can provide the required accuracy and update rate. A 3D UWB TOA tracking system with two-way ranging has been proposed and studied. The designed system will be tested in the Wireless Habitat Testbed which simulates the ISS module environment. In this presentation, we discuss the 3D TOA tracking algorithm and the performance evaluation based on different tracking baseline configurations. The simulation results show that two configurations of the tracking baseline are feasible. With 100 picoseconds standard deviation (STD) of TOA estimates, the average tracking error 0.2392 feet (about 7 centimeters) can be achieved for configuration Twisted Rectangle while the average tracking error 0.9183 feet (about 28 centimeters) can be achieved for configuration Slightly-Twisted Top Rectangle . The tracking accuracy can be further improved with the improvement of the STD of TOA estimates. With 10 picoseconds STD of TOA estimates, the average tracking error 0.0239 feet (less than 1 centimeter) can be achieved for configuration "Twisted Rectangle".

Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Dusl, John

2012-01-01

68

Microstrip-fed printed lotus antenna for wideband wireless communication systems  

Microsoft Academic Search

A novel printed antenna, fed by a microstrip line, has been designed for wideband wireless communication systems. The new antenna shows a wide -10dB bandwidth of over 60%. In addition to being small in size, the antenna exhibits stable far-field radiation characteristics in the entire operating band with relatively high gain, low cross polarization, wide beamwidth, and good front-to-back ratio.

A. A. Eldek; A. Z. Elsherbeni; Charles E. Smith

2004-01-01

69

A carrier leakage calibration and compensation technique for wideband wireless transceiver  

NASA Astrophysics Data System (ADS)

A carrier leakage calibration and compensation technique based on digital baseband for a wideband wireless communication transceiver is proposed. The digital baseband transmits a calibration signal, samples the signal which passes through the transmitter path and the calibration loop in the RF chip, measures the carrier leakage by analyzing the sampled data and compensates it. Compared with a self-calibration technique in the RF chip, the proposed technique saves area and power consumption for the wireless local area network (WLAN) solution. This technique has been successfully used for 802.1 1n system and satisfies the requirement of the standard by achieving over 50 dB carrier leakage suppression.

Liguo, Zhou; Jin, Peng; Fang, Yuan; Zhi, Fang; Jun, Yan; Yin, Shi

2014-06-01

70

Performance of ultra-wideband communications with suboptimal receivers in multipath channels  

Microsoft Academic Search

The performance of a single-user ultra-wideband (UWB) communication system employing binary block-coded pulse-position modulation (PPM) and suboptimal receivers in multipath channels is considered. The receivers examined include a RAKE receiver with various diversity combining schemes and an autocorrelation receiver, which is used in conjunction with transmitted reference (TR) signaling. A general framework is provided for deriving the performance of these

John D. Choi; Wayne E. Stark

2002-01-01

71

Optimal Channel Energy Capture for Ultra-Wideband Transmitted Reference Systems in Clustered Channels  

Microsoft Academic Search

Due to the large signal bandwidth of an ultra-wideband (UWB) transmitted reference (TR) system, the clustering channel statistics, as defined in the IEEE 802.15.3a channel models, should be taken into account in performance characterization. In this paper, we address the optimal mean channel energy capture for the maximal signal-to-interference-plus-noise ratio (SINR) regarding the special UWB channel statistics. It is analytically

Chi-Hsuan Hsieh; Wei-De Wu; Chi-Chao Chao

2010-01-01

72

Characterization of inter-pulse interference and fading for ultra-wideband systems  

Microsoft Academic Search

A statistical characterization is presented of the im- pact of the ultra-wideband (UWB) multipath channel on impulse radio and spread-spectrum UWB systems. For this purpose, the correlator output statistics are studied, since correlators are the typical first processing step in the frontends of coherent and noncoherent receivers. The analysis is based on the second and forth-order moments of the channel

Klaus Witrisal; Marco Pausini

2011-01-01

73

Three-ray path loss based on peak power loss for ultra wideband impulse radio systems  

Microsoft Academic Search

Path loss is important parameter to analyze and design link budget. For indoor environment, there is fading that occurs in path loss. Therefore, accurate path loss model, which is considered fading, is necessary. In this paper, three-ray path loss based on peak power loss is proposed for ultra wideband impulse radio (UWB-IR) systems. The rectangular passband is used as UWB-IR

Pichaya Supanakoon; Saksit Chaiyapong; Sathaporn Promwong; Jun-ichi Takada

2011-01-01

74

Path-loss exponents of ultra wideband signals in line-of-sight environments  

Microsoft Academic Search

The paper proposes a new ultra wideband (UWB) line-of-sight path loss formula based on the narrowband two-path (direct and ground reflected waves) model, taking into account the bandwidth of signals. The following results were derived from numerical calculations: (1) UWB signals suffer less interference fading than narrowband signals; (2) UWB path loss exponents change approximately to 2 to 4 around

Shunsuke Sato; Takehiko Kobayashi

2004-01-01

75

A Low-Power CMOS Modulator for Ultra-Wideband Transmitters  

Microsoft Academic Search

A low-power CMOS modulator for carrier-based ultra-wideband (UWB) transmitters is presented. The core of the circuit consists of an oscillator and two control switches. The oscillator sets the center frequency of the UWB signal. The spectrum of the baseband data pulse is frequency translated to the desired band without using an explicit mixer. Since in many pulse-based UWB systems, in

Shahrzad Jalali Mazlouman; Alireza Mahanfar; Shahriar Mirabbasi

2007-01-01

76

On the Array Performance of Printed, Ultra-Wideband “Eared” Antennas  

Microsoft Academic Search

The performance of an ultra-wideband (UWB) radiator is examined in a 15-element linear-array environment. The numerically predicted array impedance is validated by means of physical measurements. The broadside scanned radiation patterns of the array are measured and proven to be extremely favorable. A zoom-in on the measured elementary radiation patterns is employed for evidencing the effect of embedding the radiator

F. Muge Tanyer-Tigrek; Ioan E. Lager; Leonardus P. Ligthart

2011-01-01

77

Ultra-wideband (UWB) bandpass filters using multiple-mode resonator  

Microsoft Academic Search

A novel microstrip-line ultra-wideband (UWB) bandpass filter is proposed and implemented using a multiple-mode resonator (MMR), aiming at transmitting the signals in the whole UWB passband of 3.1-10.6GHz. In the design, the first three resonant frequencies of this MMR are properly adjusted to be placed quasiequally within the UWB. Then, the parallel-coupled lines at the two sides are longitudinally stretched

Lei Zhu; Sheng Sun; Wolfgang Menzel

2005-01-01

78

Simulation of ultra wide-band communication systems  

Microsoft Academic Search

The objective is to present and analyse the UWB communication systems signal processing point of view on the receiver side, with the purpose of using the technology for wireless high data-rate short range communication. The simulation was to use the tedious Monte-Carlo simulation to match the semi-analytic experiment shown in the original paper (M.Z. Win and R.A. Scholtz, 1998). This

S. H. Chen; P. Shum; E. H. Chua

2005-01-01

79

Ultra-wideband radios for time-of-flight-ranging and network position estimation  

DOEpatents

This invention provides a novel high-accuracy indoor ranging device that uses ultra-wideband (UWB) RF pulsing with low-power and low-cost electronics. A unique of the present invention is that it exploits multiple measurements in time and space for very accurate ranging. The wideband radio signals utilized herein are particularly suited to ranging in harsh RF environments because they allow signal reconstruction in spite of multipath propagation distortion. Furthermore, the ranging and positioning techniques discussed herein directly address many of the known technical challenges encountered in UWB localization regarding synchronization and sampling. In the method developed, noisy, corrupted signals can be recovered by repeating range measurements across a channel, and the distance measurements are combined from many locations surrounding the target in a way that minimizes the range biases associated to indirect flight paths and through-wall propagation delays.

Hertzog, Claudia A. (Houston, TX); Dowla, Farid U. (Castro Valley, CA); Dallum, Gregory E. (Livermore, CA); Romero, Carlos E. (Livermore, CA)

2011-06-14

80

S - C - L triple wavelength superluminescent source based on an ultra-wideband SOA and FBGs  

NASA Astrophysics Data System (ADS)

We propose and demonstrate a wide-band semiconductor optical amplifier (SOA) based triple-wavelength superluminescent source with the output in the S-, C- and L-band regions. The proposed systems uses an ultra-wideband SOA with an amplification range from 1440 to 1620 nm as the linear gain medium. Three fibre Bragg gratings (FBGs) with centre wavelengths of 1500, 1540 and 1580 nm are used to generate the lasing wavelengths in the S-, Cand L-bands respectively, while a variable optical attenuator is used to finely balance the optical powers of the lasing wavelengths. The ultra-wideband SOA generates an amplified spontaneous emission (ASE) spectrum with a peak power of -33 dBm at the highest SOA drive current, and also demonstrates a down-shift in the centre wavelength of the generated spectrum due to the spatial distribution of the carrier densities. The S-band wavelength is the dominant wavelength at high drive currents, with an output power of -6 dBm as compared to the C- and L-bands, which only have powers of -11 and -10 dBm, respectively. All wavelengths have a high average signal-to-noise ratio more than 60 dB at the highest drive current of 390 mA, and the system also shows a high degree of stability, with power fluctuations of less than 3 dB within 70 min. The proposed system can find many applications where a wide-band and stable laser source is crucial, such as in communications and sensing.

Ahmad, H.; Zulkifli, M. Z.; Hassan, N. A.; Muhammad, F. D.; Harun, S. W.

2013-10-01

81

Performance Evaluation of a 60-GHz Multi-band OFDM (MB-OFDM) Ultra-Wideband Radio-Over-Fibre System  

E-print Network

Performance Evaluation of a 60-GHz Multi-band OFDM (MB-OFDM) Ultra-Wideband Radio-Over-Fibre System O Omomukuyo and J E Mitchell University College London Abstract: In this paper, we present-Over-Fibre (RoF) system for Ultra- Wideband (UWB) applications in the 60-GHz radio band. We have made use of two

Haddadi, Hamed

82

An iterative procedure for ultra-wideband imagery of space objects from distributed multi-band radar data  

NASA Astrophysics Data System (ADS)

A novel technique is proposed for ultra-wideband imagery of space objects from distributed multi-band radar data. The complex exponential (CE) model is used for representation of ultra-wideband radar signals, where an iterative procedure is developed for optimized model parameter estimation. A subband coherent processing technique is developed which combines the de-noising cross-correlation (DNCC) algorithm with statistical method to obtain the phase and amplitude incoherent parameters (ICP) between subbands. Ultra-wideband data fusion via two-dimensional gapped-data state space approach (2-D GSSA) is then applied to multiple subband signals for supper-resolution imagery. Experiments using computational electromagnetic data from the method of moment (MoM) as well as anechoic chamber measurement data are used to validate the proposed technique and demonstrate its applications.

Xu, Xiaojian; He, Feiyang

2014-09-01

83

Compact Electromagnetic Bandgap Structures for Notch Band in Ultra-Wideband Applications  

PubMed Central

This paper introduces a novel approach to create notch band filters in the front-end of ultra-wideband (UWB) communication systems based on electromagnetic bandgap (EBG) structures. The concept presented here can be implemented in any structure that has a microstrip in its configuration. The EBG structure is first analyzed using a full wave electromagnetic solver and then optimized to work at WLAN band (5.15–5.825 GHz). Two UWB passband filters are used to demonstrate the applicability and effectiveness of the novel EBG notch band feature. Simulation results are provided for two cases studied. PMID:22163430

Rotaru, Mihai; Sykulski, Jan

2010-01-01

84

Ultra-wideband microwave imaging of breast cancer tumors via Bayesian inverse scattering  

NASA Astrophysics Data System (ADS)

We develop a new algorithm for ultra-wideband (UWB) microwave imaging of breast cancer tumors using Bayesian inverse scattering. A key feature of the proposed algorithm is that constitutive properties of breast tissues are reconstructed from scattered UWB microwave signals together with the confidence level of the reconstruction. Having such confidence level enables minimization of both false alarms and missed detections. Results from the application of the proposed algorithm demonstrate the accuracy in estimating both location and permittivity of breast tumors without the need for a priori knowledge of pointwise properties of the background breast tissue.

Fouda, A. E.; Teixeira, F. L.

2014-02-01

85

Ultra wideband technology for aircraft wireless intercommunications systems (AWICS) design  

Microsoft Academic Search

Current intercommunications system (ICS) designs for military, multicrew aircraft utilize lengthy, encumbering cords to physically attach the crewmember's helmet or headset to a distributed audio intercom system. Typical ICS long-cords are approximately 100 feet in length and allow crewmembers to maintain communications as they move about the aircraft while performing their mission duties. These cords also allow crewmembers to maintain

Aitan Ameti; Robert J. Fontana; E. J. Knight; Edward Richley

2004-01-01

86

Ultra-Wideband GPR Imaging of the Vaucluse Karst Aquifer  

NASA Astrophysics Data System (ADS)

In this paper, we present the validation of an Ultra Wide band measurement system which is the first experimental step of the French MAXWELL Research Project devoted to the survey of the karst aquifer located in the Vaucluse in Provence. This radar system employs Exponentially Tapered Slot Antennas (ETSA), with a usable bandwidth from 100 MHz to 2.5 GHz. The antenna is driven by a .01- 26.5 GHz Agilent vector network analyzer (VNA), with a noise floor of -120dB under test conditions and a noise floor of -100 dB in a field setting. A synthetic pulse is applied to the antenna by using a classical step frequency sweeping. The recorded amplitudes and phases of the reflection coefficient (S11 parameter) are filtered and inverse Fourier transformed to obtain the time-domain data. In principal, due to the flat radiation characteristic of the frequency generator, appropriate synthetic pulses can be generated for analysis. The advantages of this approach are mainly, 1) a large depth resolution due to increased bandwidth, 2) a wider dynamic range for detection of weak late underground echoes, 3) a low signal distortion due to absence of pulse deconvolution post-processing. The foregoing system was deployed inside a tunnel in the Low-Noise Underground Laboratory (LSBB) located in Rustrel (France) which allows the use of low power radiation. Minimization of noise interference was accomplished by : 1) using low noise and low-loss cables, 2) using a PVC structure covered with absorbers to shield the ETSA from unwanted tunnel wall reflections and from radiation from the vector network analyzer, 3) an effective calibration of long cables to the antenna connector with careful cable unwinding to reduce phase errors, 4) a power level fixed at 8 dBm in the frequency band of interest to avoid distortion in the mixer of the VNA. Monostatic or multistatic data, were collected by moving manually the antennas along the PVC frame, in 5 cm increments over a length of 6 m. Both parallel and perpendicular polarizations were recorded. Data were obtained from 150 MHz to 2 GHz to reduce any reflections from the connection to the analyzer. Time sections were then processed after an inverse Fourier transform. To validate our results (from a geophysics point of view), reference data were also collected using 100, 250 and 500 MHz RAMAC GPR systems. Results are very promising especially regarding the resolution of the images, depth penetration and low emitting power. In future experiments, our approach could be still improved by using shorter cables, high directive antennas and absorbers to reduce coupling in multistatic configurations.

Dauvignac, J.; Fortino, N.; Sénéchal, G.; Cresp, A.; Yedlin, M.; Gaffet, S.; Rousset, D.; Pichot, C.

2008-12-01

87

Contemporary Wireless Technology  

NSDL National Science Digital Library

Wireless means radio in its broadest sense. However, in the early 21st century, wireless refers primarily to the two dominant forms of wireless: cell phones and wireless local area networks (WLANs). This module describes the idea behind the cellular telephone system, how it works, and the primary technologies used in the US and throughout the world. This module also introduces the wireless local area network or WLAN. WLANs are radio-linked computers that are part of a larger network. The wireless links make portability and mobility of computers possible. This module also briefly introduces four common forms of short- range wireless: Bluetooth, ZigBee, ultra wideband (UWB) and RFID.

2012-08-21

88

Detection of target scattering centers in terrain clutter using an ultra-wideband, fully-polarimetric synthetic aperture radar  

Microsoft Academic Search

We study the processing of full-polarization data collected by an ultra-wideband synthetic aperture radar in order to detect targets embedded in terrain clutter. We focus on the use of polarization diversity in a high resolution application to incorporate partial knowledge of the target into the detector design and to model geometrically relevant unknown parameters. We consider a family of generalized

Ronald Louis Dilsavor

1993-01-01

89

Detection of Physics-based Ultra-wideband Signals Using Generalized RAKE in Presence of Inter-Symbol Interference  

E-print Network

Detection of Physics-based Ultra-wideband Signals Using Generalized RAKE in Presence of Inter-Symbol Interference John Qiang Zhang and Robert Caiming Qiu Abstract-- The generalized rake receiver based on physics rate. Index Terms-- Generalized rake receiver, Physics-based channel, Successive channel estimation

Qiu, Robert Caiming

90

Novel low-cost ultra-wideband, ultra-short-pulse transmitter with MESFET impulse-shaping circuitry for reduced distortion and improved pulse repetition rate  

Microsoft Academic Search

A new ultra-wideband, ultra-short-pulse transmitter has been developed using microstrip lines, step-recovery and Schottky diodes, MESFET, and monolithic microwave integrated circuit (MMIC) amplifier. This transmitter employs a novel MESFET impulse-shaping circuit to achieve several unique advantages, including less distortion, easy broadband matching, and increased pulse repetition rate. The transmitter produces 300-ps monocycle pulses with about 2 V peak-to-peak and a

Jeong Soo Lee; Cam Nguyen

2001-01-01

91

Design and analysis of new printed wideband antennas for wireless applications  

NASA Astrophysics Data System (ADS)

In this study a simple method to develop a wideband antenna is proposed. With this new technique a dipole antenna with a 48% frequency bandwidth is transformed to achieve a 120% frequency bandwidth for a voltage standing-wave ratio ? 2. Two different designs are tested and their performance is compared: the segmented-ring antenna and the split-ring antenna. Both antennas achieved a stable radiation pattern and a moderate gain. Nearly omnidirectional radiation patterns have been observed in both the XZ and YZ-planes. Finally, simple passive arrays are presented, demonstrating the usefulness of the split-ring antenna as an array element. Beam steering is demonstrated with a four element passive array using horizontal meandering lines. This novel antenna has wide applications in high-capacity wireless communication system.

Asirvatham, Koby

92

Ultra-Wideband Sensors for Improved Magnetic Resonance Imaging, Cardiovascular Monitoring and Tumour Diagnostics  

PubMed Central

The specific advantages of ultra-wideband electromagnetic remote sensing (UWB radar) make it a particularly attractive technique for biomedical applications. We partially review our activities in utilizing this novel approach for the benefit of high and ultra-high field magnetic resonance imaging (MRI) and other applications, e.g., for intensive care medicine and biomedical research. We could show that our approach is beneficial for applications like motion tracking for high resolution brain imaging due to the non-contact acquisition of involuntary head motions with high spatial resolution, navigation for cardiac MRI due to our interpretation of the detected physiological mechanical contraction of the heart muscle and for MR safety, since we have investigated the influence of high static magnetic fields on myocardial mechanics. From our findings we could conclude, that UWB radar can serve as a navigator technique for high and ultra-high field magnetic resonance imaging and can be beneficial preserving the high resolution capability of this imaging modality. Furthermore it can potentially be used to support standard ECG analysis by complementary information where sole ECG analysis fails. Further analytical investigations have proven the feasibility of this method for intracranial displacements detection and the rendition of a tumour’s contrast agent based perfusion dynamic. Beside these analytical approaches we have carried out FDTD simulations of a complex arrangement mimicking the illumination of a human torso model incorporating the geometry of the antennas applied. PMID:22163498

Thiel, Florian; Kosch, Olaf; Seifert, Frank

2010-01-01

93

Free space optical ultra-wideband communications over atmospheric turbulence channels.  

PubMed

A hybrid impulse radio ultra-wideband (IR-UWB) communication system in which UWB pulses are transmitted over long distances through free space optical (FSO) links is proposed. FSO channels are characterized by random fluctuations in the received light intensity mainly due to the atmospheric turbulence. For this reason, theoretical detection error probability analysis is presented for the proposed system for a time-hopping pulse-position modulated (TH-PPM) UWB signal model under weak, moderate and strong turbulence conditions. For the optical system output distributed over radio frequency UWB channels, composite error analysis is also presented. The theoretical derivations are verified via simulation results, which indicate a computationally and spectrally efficient UWB-over-FSO system. PMID:20721053

Davaslio?lu, Kemal; Ca?iral, Erman; Koca, Mutlu

2010-08-01

94

Ultra Wide-Band Localization and SLAM: A Comparative Study for Mobile Robot Navigation  

PubMed Central

In this work, a comparative study between an Ultra Wide-Band (UWB) localization system and a Simultaneous Localization and Mapping (SLAM) algorithm is presented. Due to its high bandwidth and short pulses length, UWB potentially allows great accuracy in range measurements based on Time of Arrival (TOA) estimation. SLAM algorithms recursively estimates the map of an environment and the pose (position and orientation) of a mobile robot within that environment. The comparative study presented here involves the performance analysis of implementing in parallel an UWB localization based system and a SLAM algorithm on a mobile robot navigating within an environment. Real time results as well as error analysis are also shown in this work. PMID:22319397

Segura, Marcelo J.; Auat Cheein, Fernando A.; Toibero, Juan M.; Mut, Vicente; Carelli, Ricardo

2011-01-01

95

Ultra wide-band localization and SLAM: a comparative study for mobile robot navigation.  

PubMed

In this work, a comparative study between an Ultra Wide-Band (UWB) localization system and a Simultaneous Localization and Mapping (SLAM) algorithm is presented. Due to its high bandwidth and short pulses length, UWB potentially allows great accuracy in range measurements based on Time of Arrival (TOA) estimation. SLAM algorithms recursively estimates the map of an environment and the pose (position and orientation) of a mobile robot within that environment. The comparative study presented here involves the performance analysis of implementing in parallel an UWB localization based system and a SLAM algorithm on a mobile robot navigating within an environment. Real time results as well as error analysis are also shown in this work. PMID:22319397

Segura, Marcelo J; Auat Cheein, Fernando A; Toibero, Juan M; Mut, Vicente; Carelli, Ricardo

2011-01-01

96

An ultra-wideband transmit/receive module using 10 to 35 GHz six-channel microstrip multiplexers and its applications to phased-array antenna transceiver systems  

E-print Network

developed. Recent advances in broadband monolithic microwave integrated circuit (MMIC) amplifiers make the realization of extremely broadband phased-array transceiver systems possible. The ultra-wideband phased-array transceiver systems can be used in multi...

Hong, Seung Pyo

2006-10-30

97

An Ultra-Wearable, Wireless, Low Power ECG Monitoring System  

E-print Network

An Ultra-Wearable, Wireless, Low Power ECG Monitoring System Chulsung Park and Pai H. Chou., Suite 107 San Diego, CA 92121, USA Abstract-- Wearable electrocardiograph (ECG) monitoring systems today performance to gold standard ECG electrodes, has been developed. This paper presents a description

Shinozuka, Masanobu

98

Ultra low-power radio design for wireless sensor networks  

Microsoft Academic Search

Power consumption and size are the most important challenges faced when designing radios for distributed wireless sensor networks (WSN). Reducing power consumption requires optimization across all the layers of the communication systems. Although the MAC layer plays a crucial role in the overall energy efficiency, the radio remains one of the bottleneck for implementing ultra low-power WSN. The power consumption

C. Enz; N. Scolari; U. Yodprasit

2005-01-01

99

ICUWB 2009 to Focus on Microvave and Millimeter Wave Band Technology, IEEE International Conference on Ultra-Wideband will Meet on 9–11 September 2009 in Vancouver  

Microsoft Academic Search

IEEE International Conference on Ultra-Wideband Will Meet on 9 - 11 September 2009 in Vancouver In Vancouver on 9-11 September, the 2009 IEEE International Conference on Ultra-Wideband will center around the topic of UWB transmission in micro-wave and millimeter wave bands and over power lines. It will focus on the latest advances in UWB technology, current and future applications ranging

Lutz Lampe

2008-01-01

100

A statistical ultra-wideband indoor channel model and the effects of antenna directivity on path loss and multipath propagation  

Microsoft Academic Search

Ultra-wideband indoor line-of-sight frequency-domain channel measurements have been performed in the 2-6 GHz frequency band using three different transmit\\/receive antenna combination pairs. The effects of antenna directivity on path loss and multipath propagation in the channel are analyzed extensively for various omnidirectional and directional antenna combinations. A statistical model of the path loss in the channel is presented, in which

Jason A. Dabin; Alexander M. Haimovich; Haim Grebel

2006-01-01

101

An ultra-wideband printed monopole antenna with the gain enhanced using a surface-mounted short horn  

Microsoft Academic Search

An ultra-wideband printed monopole antenna, improved by attaching a short two-plate horn to its surface, is reported in this paper. The short horn, which has a slant length of 45 mm and a total physical height of 46.9 mm, significantly increases the gain of the printed monopole antenna at lower frequencies where the gain of the monopole is otherwise low,

Y. Ranga; Karu P. Esselle; A. R. Weily; A. K. Verma

2010-01-01

102

Analysis of Ultra-Wideband Printed Planar Quasi-Monopole Antennas Using the Theory of Characteristic Modes  

Microsoft Academic Search

This paper presents an analysis of ultra-wideband (UWB) printed planar quasi-monopole antennas using the theory of characteristic modes. It is shown that the modal voltage-standing-wave ratio, mode current distribution, and modal significance provide deeper physical insight into the operating mechanisms of these popular types of antennas. Using the printed planar bevel-shaped quasi-monopole antenna as an example, we characterize the antenna's

Weixia Wu; Y. P. Zhang

2010-01-01

103

ULTRA SECURE HIGH RELIABILITY WIRELESS RADIATION MONITOR  

SciTech Connect

Radiation monitoring in nuclear facilities is essential to safe operation of the equipment as well as protecting personnel. In specific, typical air monitoring of radioactive gases or particulate involves complex systems of valves, pumps, piping and electronics. The challenge is to measure a representative sample in areas that are radioactively contaminated. Running cables and piping to these locations is very expensive due to the containment requirements. Penetration into and out of an airborne or containment area is complex and costly. The process rooms are built with thick rebar-enforced concrete walls with glove box containment chambers inside. Figure 1 shows high temperature radiation resistance cabling entering the top of a typical glove box. In some case, the entire processing area must be contained in a 'hot cell' where the only access into the chamber is via manipulators. An example is shown in Figure 2. A short range wireless network provides an ideal communication link for transmitting the data from the radiation sensor to a 'clean area', or area absent of any radiation fields or radioactive contamination. Radiation monitoring systems that protect personnel and equipment must meet stringent codes and standards due to the consequences of failure. At first glance a wired system would seem more desirable. Concerns with wireless communication include latency, jamming, spoofing, man in the middle attacks, and hacking. The Department of Energy's Savannah River National Laboratory (SRNL) has developed a prototype wireless radiation air monitoring system that address many of the concerns with wireless and allows quick deployment in radiation and contamination areas. It is stand alone and only requires a standard 120 VAC, 60 Hz power source. It is designed to be mounted or portable. The wireless link uses a National Security Agency (NSA) Suite B compliant wireless network from Fortress Technologies that is considered robust enough to be used for classified data transmission in place of NSA Type 1 devices.

Cordaro, J.; Shull, D.; Farrar, M.; Reeves, G.

2011-08-03

104

Zpectrometer: an Ultra-wideband Spectrometer for Redshift Searches with the Green Bank Telescope  

NASA Astrophysics Data System (ADS)

To understand the cosmic histories of star formation and accretion, observers must determine the redshifts of distant galaxies whose central starbursts and/or active nuclei are heavily obscured by dust. Direct spectroscopy of molecular emission lines is the ideal way to meet this challenge, but a suitable instrument must have large instantaneous bandwidth to achieve broad redshift coverage. We describe a new, ultra-wideband "Zpectrometer" now under construction for the Green Bank Telescope that satisfies this need. Using a novel analog lag cross-correlator spectrometer technology in a correlation radiometer architecture, the Zpectrometer will produce stable spectra over the entire 26-40 GHz range of the GBT's Ka-band receiver. The Zpectrometer will enable blind searches for CO(1-0) emission in the redshift range where the cosmic star formation rate density peaks, higher-J CO transitions at earlier epochs, and rotational lines from other molecules at a variety of redshifts. This project is funded by a National Science Foundation ATI Program grant to the University of Maryland and by contributions from the National Radio Astronomy Observatory.

Baker, A. J.; Harris, A. I.; Jewell, P. R.; Rauch, K. P.; Zonak, S. G.; O'Neil, K.; Shelton, A. L.; Norrod, R. D.; Ray, J.; Watts, G.

2005-12-01

105

Ultra-compact optical true time delay device for wideband phased array radars  

NASA Astrophysics Data System (ADS)

An ultra-compact optical true time delay device is demonstrated that can support 112 antenna elements with better than six bits of delay in a volume 16"×5"×4" including the box and electronics. Free-space beams circulate in a White cell, overlapping in space to minimize volume. The 18 mirrors are slow-tool diamond turned on two substrates, one at each end, to streamline alignment. Pointing accuracy of better than 10?rad is achieved, with surface roughness ~45 nm rms. A MEMS tip-style mirror array selects among the paths for each beam independently, requiring ~100 ?s to switch the whole array. The micromirrors have 1.4° tip angle and three stable states (east, west, and flat). The input is a fiber-and-microlens array, whose output spots are re-imaged multiple times in the White cell, striking a different area of the single MEMS chip in each of 10 bounces. The output is converted to RF by an integrated InP wideband optical combiner detector array. Delays were accurate to within 4% (shortest delay) to 0.03% (longest mirror train). The fiber-to-detector insertion loss is 7.82 dB for the shortest delay path.

Anderson, Betty Lise; Ho, James G.; Cowan, William D.; Spahn, Olga B.; Yi, Allen Y.; Flannery, Martin R.; Rowe, Delton J.; McCray, David L.; Rabb, David J.; Chen, Peter

2010-04-01

106

Ultra-compact optical true time delay device for wideband phased array radars.  

SciTech Connect

An ultra-compact optical true time delay device is demonstrated that can support 112 antenna elements with better than six bits of delay in a volume 16-inch x 5-inch x 4-inch including the box and electronics. Free-space beams circulate in a White cell, overlapping in space to minimize volume. The 18 mirrors are slow-tool diamond turned on two substrates, one at each end, to streamline alignment. Pointing accuracy of better than 10 {micro}rad is achieved, with surface roughness {approx}45 nm rms. A MEMS tip-style mirror array selects among the paths for each beam independently, requiring {approx}100 {micro}s to switch the whole array. The micromirrors have 1.4{sup o} tip angle and three stable states (east, west, and flat). The input is a fiber-and-microlens array, whose output spots are re-imaged multiple times in the White cell, striking a different area of the single MEMS chip in each of 10 bounces. The output is converted to RF by an integrated InP wideband optical combiner detector array. Delays were accurate to within 4% (shortest delay) to 0.03% (longest mirror train). The fiber-to-detector insertion loss is 7.82 dB for the shortest delay path.

Spahn, Olga Blum; Rabb, David J. (AFRL/RYJM, WPAFB, OH); Cowan, William D.; McCray, David L. (Ohio State University, Columbus, OH); Rowe, Delton, J. (Northrop Grumman Aerospace Systems, Redondo Beach, CA); Flannery, Martin R. (Northrop Grumman Aerospace Systems, Redondo Beach, CA); Yi, Allen Y. (Ohio State University, Columbus, OH); Ho, James G. (Northrop Grumman Aerospace Systems, Redondo Beach, CA); Anderson, Betty Lise (Ohio State University, Columbus, OH)

2010-02-01

107

Group Delay in THz Spectroscopy with Ultra-Wideband Log-Spiral Antennae  

NASA Astrophysics Data System (ADS)

We report on the group delay observed in continuous-wave terahertz spectroscopy based on photomixing with phase-sensitive homodyne detection. We discuss the different contributions of the experimental setup to the phase difference ? ?( ?) between transmitter arm and receiver arm. A simple model based on three contributions yields a quantitative description of the overall behavior of ? ?( ?). Firstly, the optical path-length difference gives rise to a term linear in frequency ?. Secondly, the ultra-wideband log-spiral antennae effectively radiate and receive in a frequency-dependent active region, which in the most simple model is an annular area with a circumference equal to the wavelength. The corresponding term changes by roughly 6 ? between 100 GHz and 1 THz. The third contribution stems from the photomixer impedance. In contrast, the derivative ?? ?/ ? ? is dominated by the contribution of periodic modulations of ? ?( ?) caused by standing waves, e.g., in the photomixers' Si lenses. Furthermore, we discuss the Fourier-transformed spectra, which are equivalent to the waveform in a time-domain experiment. In the time domain, the group delay introduced by the log-spiral antennae gives rise to strongly chirped signals, in which low frequencies are delayed. Correcting for the contributions of antennae and photomixers yields sharp peaks or "pulses" and thus facilitates a time-domain-like analysis of our continuous-wave data.

Langenbach, M.; Roggenbuck, A.; Cámara Mayorga, I.; Deninger, A.; Thirunavukkuarasu, K.; Hemberger, J.; Grüninger, M.

2014-11-01

108

Ultra-Wideband Time-Difference-of-Arrival High Resolution 3D Proximity Tracking System  

NASA Technical Reports Server (NTRS)

This paper describes a research and development effort for a prototype ultra-wideband (UWB) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being studied for use in tracking of lunar./Mars rovers and astronauts during early exploration missions when satellite navigation systems are not available. U IATB impulse radio (UWB-IR) technology is exploited in the design and implementation of the prototype location and tracking system. A three-dimensional (3D) proximity tracking prototype design using commercially available UWB products is proposed to implement the Time-Difference- Of-Arrival (TDOA) tracking methodology in this research effort. The TDOA tracking algorithm is utilized for location estimation in the prototype system, not only to exploit the precise time resolution possible with UWB signals, but also to eliminate the need for synchronization between the transmitter and the receiver. Simulations show that the TDOA algorithm can achieve the fine tracking resolution with low noise TDOA estimates for close-in tracking. Field tests demonstrated that this prototype UWB TDOA High Resolution 3D Proximity Tracking System is feasible for providing positioning-awareness information in a 3D space to a robotic control system. This 3D tracking system is developed for a robotic control system in a facility called "Moonyard" at Honeywell Defense & System in Arizona under a Space Act Agreement.

Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Dekome, Kent; Dusl, John

2010-01-01

109

Ultra-High Temperature Distributed Wireless Sensors  

SciTech Connect

Research was conducted towards the development of a passive wireless sensor for measurement of temperature in coal gasifiers and coal-fired boiler plants. Approaches investigated included metamaterial sensors based on guided mode resonance filters, and temperature-sensitive antennas that modulate the frequency of incident radio waves as they are re-radiated by the antenna. In the guided mode resonant filter metamaterial approach, temperature is encoded as changes in the sharpness of the filter response, which changes with temperature because the dielectric loss of the guided mode resonance filter is temperature-dependent. In the mechanically modulated antenna approach, the resonant frequency of a vibrating cantilever beam attached to the antenna changes with temperature. The vibration of the beam perturbs the electrical impedance of the antenna, so that incident radio waves are phase modulated at a frequency equal to the resonant frequency of the vibrating beam. Since the beam resonant frequency depends on temperature, a Doppler radar can be used to remotely measure the temperature of the antenna. Laboratory testing of the guided mode resonance filter failed to produce the spectral response predicted by simulations. It was concluded that the spectral response was dominated by spectral reflections of radio waves incident on the filter. Laboratory testing of the mechanically modulated antenna demonstrated that the device frequency shifted incident radio waves, and that the frequency of the re-radiated waves varied linearly with temperature. Radio wave propagation tests in the convection pass of a small research boiler plant identified a spectral window between 10 and 13 GHz for low loss propagation of radio waves in the interior of the boiler.

May, Russell; Rumpf, Raymond; Coggin, John; Davis, Williams; Yang, Taeyoung; O'Donnell, Alan; Bresnahan, Peter

2013-03-31

110

An FDD wideband CDMA MAC protocol with minimum-power allocation and GPS-scheduling for wireless wide area multimedia networks  

Microsoft Academic Search

A frequency division duplex (FDD) wideband code division multiple access (CDMA) medium access control (MAC) protocol is developed for wireless wide area multimedia networks. In order to reach the maximum system capacity and guarantee the heterogeneous bit error rates (BERs) of multimedia traffic, a minimum-power allocation algorithm is first derived, where both multicode (MC) and orthogonal variable spreading factor (OVSF)

Xudong Wang

2005-01-01

111

An FDD Wideband CDMA MAC Protocol with Minimum-Power Allocation and GPS-Scheduling for Wireless Wide Area Multimedia Networks  

Microsoft Academic Search

In this paper, a frequency division duplex (FDD) wideband code division multiple access (CDMA) medium access control (MAC) protocol is developed for wireless wide area multimedia networks. In order to reach the maximum system capacity and guarantee the heterogeneous bit error rates (BERs) of multimedia traffic, a minimum-power allocation algorithm is first derived, where both multicode (MC) and orthogonal variable

Xudong Wang

2005-01-01

112

Wide-band E-shaped patch antennas for wireless communications  

Microsoft Academic Search

This paper presents a novel single-patch wide-band microstrip antenna: the E-shaped patch antenna. Two parallel slots are incorporated into the patch of a microstrip antenna to expand it bandwidth. The wide-band mechanism is explored by investigating the behavior of the currents on the patch. The slot length, width, and position are optimized to achieve a wide bandwidth. The validity of

Fan Yang; Xue-Xia Zhang; Xiaoning Ye; Y. Rahmat-Samii

2001-01-01

113

Ultra-miniature wireless temperature sensor for thermal medicine applications  

NASA Astrophysics Data System (ADS)

This study presents a prototype design of an ultra-miniature, wireless, battery-less, and implantable temperature-sensor, with applications to thermal medicine such as cryosurgery, hyperthermia, and thermal ablation. The design aims at a sensory device smaller than 1.5 mm in diameter and 3 mm in length, to enable minimally invasive deployment through a hypodermic needle. While the new device may be used for local temperature monitoring, simultaneous data collection from an array of such sensors can be used to reconstruct the 3D temperature field in the treated area, offering a unique capability in thermal medicine. The new sensory device consists of three major subsystems: a temperature-sensing core, a wireless data-communication unit, and a wireless power reception and management unit. Power is delivered wirelessly to the implant from an external source using an inductive link. To meet size requirements while enhancing reliability and minimizing cost, the implant is fully integrated in a regular foundry CMOS technology (0.15 ?m in the current study), including the implant-side inductor of the power link. A temperature-sensing core that consists of a proportional-to-absolute-temperature (PTAT) circuit has been designed and characterized. It employs a microwatt chopper stabilized op-amp and dynamic element-matched current sources to achieve high absolute accuracy. A second order sigma-delta (?-?) analog-to-digital converter (ADC) is designed to convert the temperature reading to a digital code, which is transmitted by backscatter through the same antenna used for receiving power. A high-efficiency multi-stage differential CMOS rectifier has been designed to provide a DC supply to the sensing and communication subsystems. This paper focuses on the development of the all-CMOS temperature sensing core circuitry part of the device, and briefly reviews the wireless power delivery and communication subsystems.

Khairi, Ahmad; Hung, Shih-Chang; Paramesh, Jeyanandh; Fedder, Gary; Rabin, Yoed

2011-03-01

114

Millimeter-wave silicon-based ultra-wideband automotive radar transceivers  

NASA Astrophysics Data System (ADS)

Since the invention of the integrated circuit, the semiconductor industry has revolutionized the world in ways no one had ever anticipated. With the advent of silicon technologies, consumer electronics became light-weight and affordable and paved the way for an Information-Communication-Entertainment age. While silicon almost completely replaced compound semiconductors from these markets, it has been unable to compete in areas with more stringent requirements due to technology limitations. One of these areas is automotive radar sensors, which will enable next-generation collision-warning systems in automobiles. A low-cost implementation is absolutely essential for widespread use of these systems, which leads us to the subject of this dissertation---silicon-based solutions for automotive radars. This dissertation presents architectures and design techniques for mm-wave automotive radar transceivers. Several fully-integrated transceivers and receivers operating at 22-29 GHz and 77-81 GHz are demonstrated in both CMOS and SiGe BiCMOS technologies. Excellent performance is achieved indicating the suitability of silicon technologies for automotive radar sensors. The first CMOS 22-29-GHz pulse-radar receiver front-end for ultra-wideband radars is presented. The chip includes a low noise amplifier, I/Q mixers, quadrature voltage-controlled oscillators, pulse formers and variable-gain amplifiers. Fabricated in 0.18-mum CMOS, the receiver achieves a conversion gain of 35-38.1 dB and a noise figure of 5.5-7.4 dB. Integration of multi-mode multi-band transceivers on a single chip will enable next-generation low-cost automotive radar sensors. Two highly-integrated silicon ICs are designed in a 0.18-mum BiCMOS technology. These designs are also the first reported demonstrations of mm-wave circuits with high-speed digital circuits on the same chip. The first mm-wave dual-band frequency synthesizer and transceiver, operating in the 24-GHz and 77-GHz bands, are demonstrated. All circuits except the oscillators are shared between the two bands. A multi-functional injection-locked circuit is used after the oscillators to reconfigure the division ratio inside the phase-locked loop. The synthesizer is suitable for integration in automotive radar transceivers and heterodyne receivers for 94-GHz imaging applications. The transceiver chip includes a dual-band low noise amplifier, a shared downconversion chain, dual-band pulse formers, power amplifiers, a dual-band frequency synthesizer and a high-speed programmable baseband pulse generator. Radar functionality is demonstrated using loopback measurements.

Jain, Vipul

115

ULTRA WIDEBAND INTERFERENCE EFFECTS ON AN AMATEUR RADIO RECEIVER R. D. Wilson, R. D. Weaver, M.-H. Chung and R. A. Scholtz  

E-print Network

, which also provided samples of their standard re- ceiver test procedures. Sophisticated radio amateursULTRA WIDEBAND INTERFERENCE EFFECTS ON AN AMATEUR RADIO RECEIVER R. D. Wilson, R. D. Weaver, M. Testing was performed at the University of Southern California (USC), using the experi- mental UWB

Southern California, University of

116

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems  

Microsoft Academic Search

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement

Morey

1998-01-01

117

Accuracy of Free Space Path Loss and Matched Filter Gain Approximated by Using Passband Rectangular Pulse for Ultra Wideband Radio Systems  

Microsoft Academic Search

This paper analyzes the accuracy of free space path loss and matched filter gain approximated by using a passband rectangular pulse for ultra wideband (UWB) radio systems. The example causal signal, a modulated Gaussian pulse with the same center frequency and frequency bandwidth of the passband rectangular pulse, is used to consider the accuracy. The path loss and matched filter

Pichaya Supanakoon; Suchada Tanchotikul; Prakit Tangtisanon; Sathaporn Promwong; Jun-ichi Takada

2004-01-01

118

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC  

E-print Network

(D.(D. GoeckelGoeckel, D., D. PozarPozar, D., D. SchaubertSchaubert)) #12;Short-Range Ultra: Break 10:45 AM: Antennas and Propagation Panel: Dan Schaubert, David Pozar, Won Namgoong, Bob Scholtz Pozar, Won Namgoong, Bob Scholtz, Anatoliy Boryssenko 12:00 PM: Lunch Break #12;Short-Range Ultra

Southern California, University of

119

An all-digital transmitter for pulsed ultra-wideband communication  

E-print Network

Applications like sensor networks, medical monitoring, and asset tracking have led to a demand for energy-efficient and low-cost wireless transceivers. These types of applications typically require low effective data rates, ...

Mercier, Patrick Philip

2008-01-01

120

A novel low-profile log-periodic ultra wideband feed for the dual-reflector antenna of US-SKA  

Microsoft Academic Search

We present a novel low-profile log-periodic ultra wideband (UWB) dipole antenna referred to as the Chalmers feed. The simulated results presented show that the antenna has low input reflection coefficient, low cross-polarization, constant beam width and constant phase center position over more than a decade bandwidth. The antenna can be enclosed in a volume of 0.5?L, · 0.5?L · 0.15?L

R. Olsson; P.-S. Kilda; S. Weinreb

2004-01-01

121

High level modeling of an ultra wide-band baseband transmitter in MATLAB  

Microsoft Academic Search

Wireless personal area network (WPAN) system with ranges of 4-10 m become popular in replacing wire system, technologies such as Bluetooth and ZigBee used for this purpose but due to its low data rate of 1 Mbps which is not enough for large file transfer and applications like video streaming there is a need of technology which address all these

Waqas Ali Khan; Talha Ali Khan; Muhammad Arif Ali; Shahid Abbas

2009-01-01

122

Through-the-Wall Localization of a Moving Target by Two Independent Ultra Wideband (UWB) Radar Systems  

PubMed Central

In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered. PMID:24021968

Kocur, Dušan; Švecová, Mária; Rov?áková, Jana

2013-01-01

123

Technical note: a novel approach to the detection of estrus in dairy cows using ultra-wideband technology.  

PubMed

Detection of estrus is a key determinant of profitability of dairy herds, but estrus is increasingly difficult to observe in the modern dairy cow with shorter duration and less-intense estrus. Concurrent with the unfavorable correlation between milk yield and fertility, estrus-detection rates have declined to less than 50%. We tested ultra-wideband (UWB) radio technology (Thales Research & Technology Ltd., Reading, UK) for proof of concept that estrus could be detected in dairy cows (two 1-wk-long trials; n=16 cows, 8 in each test). The 3-dimensional positions of 12 cows with synchronized estrous cycles and 4 pregnant control cows were monitored continuously using UWB mobile units operating within a network of 8 base units for a period of 7d. In the study, 10 cows exhibited estrus as confirmed by visual observation, activity monitoring, and milk progesterone concentrations. Automated software was developed for analysis of UWB data to detect cows in estrus and report the onset of estrus in real time. The UWB technology accurately detected 9 out of 10 cows in estrus. In addition, UWB technology accurately confirmed all 6 cows not in estrus. In conclusion, UWB technology can accurately detect estrus and hence we have demonstrated proof of concept for a novel technology that has significant potential to improve estrus-detection rates. PMID:23910546

Homer, E M; Gao, Y; Meng, X; Dodson, A; Webb, R; Garnsworthy, P C

2013-10-01

124

Induced Mitogenic Activity in AML-12 Mouse Hepatocytes Exposed to Low-dose Ultra-Wideband Electromagnetic Radiation  

PubMed Central

Ultra–wideband (UWB) technology has increased with the use of various civilian and military applications. In the present study, we hypothesized that low-dose UWB electromagnetic radiation (UWBR) could elicit a mitogenic effect in AML-12 mouse hepatocytes, in vitro. To test this hypothesis, we exposed AML-12 mouse hepatocytes, to UWBR in a specially constructed gigahertz transverse electromagnetic mode (GTEM) cell. Cells were exposed to UWBR for 2 h at a temperature of 23°C, a pulse width of 10 ns, a repetition rate of 1 kHz, and field strength of 5–20 kV/m. UWB pulses were triggered by an external pulse generator for UWBR exposure but were not triggered for the sham exposure. We performed an MTT Assay to assess cell viability for UWBR-treated and sham-exposed hepatocytes. Data from viability studies indicated a time-related increase in hepatocytes at time intervals from 8–24 h post exposure. UWBR exerted a statistically significant (p < 0.05) dose-dependent response in cell viability in both serum-treated and serum free medium (SFM) -treated hepatocytes. Western blot analysis of hepatocyte lysates demonstrated that cyclin A protein was induced in hepatocytes, suggesting that increased MTT activity after UWBR exposure was due to cell proliferation. This study indicates that UWBR has a mitogenic effect on AML-12 mouse hepatocytes and implicates a possible role for UWBR in hepatocarcinoma. PMID:16705798

Dorsey, W. C.; Ford, B. D.; Roane, L.; Haynie, D. T.; Tchounwou, P. B.

2005-01-01

125

Tremor Acquisition System Based on UWB Wireless Sensor Network  

Microsoft Academic Search

This work suggests to quantify and analyze tremorusing an Ultra Wide-Band (UWB) Wireless Sensor Network(WSN). WSN based on UWB technology provides a new technology for non contact tremor assessment with extremely low radiation and penetration through walls. Tremor is the target symptom in the treatment of many neurological disorders such as Parkinson's disease (PD), midbrain tremor, essential tremor (ET) and

Gaddi Blumrosen; Moshe Uziel; Boris Rubinsky; Dana Porrat

2010-01-01

126

A novel impulse radio network for tactical military wireless communications  

Microsoft Academic Search

Two of the major concerns in tactical military wireless communication networks are covertness and throughput. Impulse radio is an ultra-wideband code division multiple access (UWB-CDMA) technique being considered as the physical layer for future networks. Impulse radio exhibits low power spectral density and relatively high immunity to fading but suffers from relatively long acquisition times. In traditional packet radio networks

Santosh S. Kolenchery; J. K. Townsend; J. A. Freebersyser

1998-01-01

127

An Ultra-Low-Power Power Management IC for Wireless Sensor Nodes  

E-print Network

An Ultra-Low-Power Power Management IC for Wireless Sensor Nodes Michael D. Seeman, Seth R. Sanders. Scavenged- power sensor nodes are now a reality with modern proces- sor, sensor and radio technology [1]. The efficiency of the scavenger-battery-load power interface path, especially at low power, is critical

Sanders, Seth

128

An ultra-low power voltage regulator for wireless sensor nodes  

Microsoft Academic Search

This paper presents an ultra-low power voltage regulator used for low power wireless sensor nodes. As the input conditions for these types of regulators can be quite different in terms of voltage range and transient speed, the introduced architecture is designed to be almost insensitive to these variations. Even if the pass device is formed by an NMOS transistor, low-dropout

Stefan Gruber; Hannes Reinisch; Hartwig Unterassinger; Martin Wiessflecker; G. Hofer; W. Pribyl; G. Holweg

2010-01-01

129

An Ultra Low Cost Wireless Communications Laboratory for Education and Research  

ERIC Educational Resources Information Center

This paper presents an ultra-low-cost wireless communications laboratory that is based on a commercial off-the-shelf field programmable gate array (FPGA) development board that is both inexpensive and available worldwide. The total cost of the laboratory is under USD $200, but it includes complete transmission, channel emulation, reception…

Linn, Y.

2012-01-01

130

Short range, ultra-wideband radar with high resolution swept range gate  

DOEpatents

A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control.

McEwan, Thomas E. (Livermore, CA)

1998-05-26

131

A 0.25-?m CMOS Low-Power UpConversion Mixer for 3.1-5 GHz Ultra-Wideband Applications  

Microsoft Academic Search

This paper presents a low-power up-conversion mixer, designed in a standard 0.25-mum CMOS technology, for 3.1-5 GHz ultra-wideband applications. The circuit provides 3.8 dB of power gain and an output-referred 1-dB compression point of -14.7 dBm, while drawing only 1.3 mA from a 1.5-V supply voltage. The 3-dB frequency bandwidth is 1.9 GHz, from 3.1 GHz to 5 GHz, and

G. Sapone; G. Palmisano

2006-01-01

132

Development of the wireless ultra-miniaturized inertial measurement unit WB-4: preliminary performance evaluation.  

PubMed

This paper presents the preliminary performance evaluation of our new wireless ultra-miniaturized inertial measurement unit (IMU) WB-4 by compared with the Vicon motion capture system. The WB-4 IMU primarily contains a mother board for motion sensing, a Bluetooth module for wireless data transmission with PC, and a Li-Polymer battery for power supply. The mother board is provided with a microcontroller and 9-axis inertial sensors (miniaturized MEMS accelerometer, gyroscope and magnetometer) to measure orientation. A quaternion-based extended Kalman filter (EKF) integrated with an R-Adaptive algorithm for automatic estimation of the measurement covariance matrix is implemented for the sensor fusion to retrieve the attitude. The experimental results showed that the wireless ultra-miniaturized WB-4 IMU could provide high accuracy performance at the angles of roll and pitch. The yaw angle which has reasonable performance needs to be further evaluated. PMID:22255931

Lin, Zhuohua; Zecca, Massimiliano; Sessa, Salvatore; Bartolomeo, Luca; Ishii, Hiroyuki; Takanishi, Atsuo

2011-01-01

133

Ultra Low-Energy Transceivers for Wireless Sensor Networks  

Microsoft Academic Search

Summary form only given. An untapped opportunity in the realm of wireless data lies in low data-rate (<10 kbit\\/sec) low-cost wireless transceivers, assembled into distributed networks of sensor and actuator nodes. This enables applications such as smart buildings and highways, environment monitoring, user interfaces, entertainment, factory automation, and robotics. While the aggregate system processes large amounts of data, individual nodes

Jan Rabaey

2002-01-01

134

Impact Of Ultra Wideband (Uwb) Radio Range On Wireless Sensor Networks  

E-print Network

ability, and low transmission power [1]-[4]. To operate in the harsh radio environment of a factory, an I and devices. Typical narrowband radios may be forced to increase their radiated power to maintain network radios in a sensor network. However, the radiated power of I-UWB radios is severely limited

Ha, Dong S.

135

Ultra-High Speed Devices for Wireless Communication Terminals (Current Status and Prospects)  

NASA Astrophysics Data System (ADS)

The technical trend of compound and Si ultra-high speed devices for wireless communication terminals is described. The choice of compound or Si devices depends on the RF frequency range and the required RF handling power. For high frequency applications and for high RF power circuit block, the compound devices still be used and new devices such as InGaP HBT has been developed. If the frequency range is below 6GHz, and the output power is limited, Si devices are becoming common for the transceiver system IC. Based on the device trends, the technical requirements for the ultra-high-speed devices for present and next-generation wireless applications are described. Developments of compound HBT PA and SiGe-RFIC’s for 3G (W-CDMA) terminals are also described and the circuit techniques used in these RF devices are introduced.

Suematsu, Noriharu

136

Smart Power Unit with Ultra Low Power Radio Trigger Capabilities for Wireless Sensor Networks  

Microsoft Academic Search

This paper presents the design, implementation and characterization of an energy–efficient smart power unit for a wireless sensor network with a versatile nano-Watt wake up radio receiver. A novel Smart Power Unit has been developed featuring multi-source energy harvesting, multi-storage adaptive recharging, electrochemical fuel cell integration, radio wake-up capability and embedded intelligence. An ultra low power on board microcontroller performs

Michele Magno; Stevan Marinkovic; Davide Brunelli; Emanuel Popovici; Brendan O'Flynn; Luca Benini

2012-01-01

137

MAC Design for Supporting Ultra Low Duty Cycle in Wireless Sensor Networks1 *Wooguil PakO  

E-print Network

MAC Design for Supporting Ultra Low Duty Cycle in Wireless Sensor Networks1 *Wooguil PakO , *Hyuk. In general, sensor medium access control (MAC) protocols reduce duty cycle to achieve longer life time.1%). Our proposed U-MAC (Ultra low duty cycle MAC) protocol targets achieving low energy consumption under

Bahk, Saewoong

138

Hardware Aware Optimization of an Ultra Low Power UWB Communication System  

Microsoft Academic Search

A wireless body area network with an average throughput of 500 kbps based on ultra-wideband pulse position modulation is considered. For a long battery autonomy a hardware aware system optimization with respect to the specific applications at hand is essential. A key feature to achieve power savings is low duty cycle signaling, and its effectiveness when combined with burst-wise transmission

Florian Troesch; Christoph Steiner; Thomas Zasowski; Thomas Burger; Armin Wittneben

2007-01-01

139

Launch device using endlessly single-mode PCF for ultra-wideband WDM transmission in graded-index multi-mode fiber.  

PubMed

We demonstrated ultra-wideband wavelength division multiplexing (WDM) transmission from 850 to 1550 nm in graded-index multi-mode fiber (GI-MMF) using endlessly single-mode photonic crystal fiber (ESM-PCF) as a launch device. Effective single-mode guidance is obtained in multi-mode fiber at all wavelengths by splicing cm-order length ESM-PCF to the transmission fiber. We achieved 3 × 10 Gbit/s WDM transmission in a 1 km-long 50-?m-core GI-MMF. We also realized penalty free 10 Gbit/s data transmission at a wavelength of 850 nm by optimizing the PCF structure. This method has the potential to achieve greater total transmission capacity for MMF systems by the addition of more wavelength channels. PMID:23187257

Ma, Lin; Hanzawa, Nobutomo; Tsujikawa, Kyozo; Azuma, Yuji

2012-10-22

140

Photonic generation of millimeter-wave ultra-wideband signal using phase modulation to intensity modulation conversion and frequency up-conversion  

NASA Astrophysics Data System (ADS)

We propose and experimentally demonstrate the generation of a pair of polarity-reversed 24 GHz millimeter-wave (MMW) ultra-wideband (UWB) monocycles. The scheme is realized by using delay interferometer (DI) based phase modulation to intensity modulation (PM-IM) conversion and carrier suppression modulation (CSM) based frequency up-conversion. The phase modulation is realized by using either electro-optic phase modulator (EOPM) or cross phase modulation (XPM) in semiconductor optical amplifier (SOA), which is an all-optical approach to obtaining baseband UWB signals, respectively. After frequency up-converted by using CSM in a Mach-Zehnder modulator (MZM), a pair of polarity-reversed 24 GHz MMW-UWB signals complying with the Federal Communication Committee (FCC) requirements is generated. The bi-phase modulation (BPM) of 24 GHz MMW-UWB signals can also be realized by electrically switching the bias voltage of delay interferometer.

Yu, Yuan; Dong, Jianji; Li, Xiang; Zhang, Xinliang

2012-04-01

141

1-cc computer using UWB-IR for wireless sensor network  

Microsoft Academic Search

An ultra-small, high-data-rate, low-power 1-cc computer (OCCC) with an UWB-IR (ultra-wideband impulse-radio) transceiver was developed for a wireless sensor network. Thanks to bear-chip implementation and a flexible printed circuit board, the size of the computer is only 1 cm3. To achieve 10-Mbps data rate, a middle-class 32-bit microcontroller, which has both a bus interface and a USB 2.0 controller, was

Tatsuo Nakagawa; Masayuki Miyazaki; Goichi Ono; Ryosuke Fujiwara; Takayasu Norimatsu; Takahide Terada; Akira Maeki; Yuji Ogata; Shinsuke Kobayashi; Noboru Koshizuka; Ken Sakamura

2008-01-01

142

Real-time sub-carrier Adaptive Modulation and Coding in wideband Orthogonal Frequency Division Multiplexing wireless systems  

E-print Network

The increasing demand for high speed wireless connectivity at low cost proposes new challenges for communication systems designers to implement solutions that increase the data rate by utilizing the limited radio resources ...

Edalat, Farinaz, 1979-

2008-01-01

143

Design of nodes for embedded and ultra low-power wireless sensor networks  

NASA Astrophysics Data System (ADS)

Sensor network integrates sensor technology, MEMS (Micro-Electro-Mechanical system) technology, embedded computing, wireless communication technology and distributed information management technology. It is of great value to use it where human is quite difficult to reach. Power consumption and size are the most important consideration when nodes are designed for distributed WSN (wireless sensor networks). Consequently, it is of great importance to decrease the size of a node, reduce its power consumption and extend its life in network. WSN nodes have been designed using JN5121-Z01-M01 module produced by jennic company and IEEE 802.15.4/ZigBee technology. Its new features include support for CPU sleep modes and a long-term ultra low power sleep mode for the entire node. In low power configuration the node resembles existing small low power nodes. An embedded temperature sensor node has been developed to verify and explore our architecture. The experiment results indicate that the WSN has the characteristic of high reliability, good stability and ultra low power consumption.

Xu, Jun; You, Bo; Cui, Juan; Ma, Jing; Li, Xin

2008-10-01

144

Design and performance of an ultra-wideband stepped-frequency radar with precise frequency control for landmine and IED detection  

NASA Astrophysics Data System (ADS)

The Army Research Laboratory (ARL) has developed an impulse-based vehicle-mounted forward-looking ultra- wideband (UWB) radar for imaging buried landmines and improvised explosive devices (IEDs). However, there is no control of the radiated spectrum in this system. As part of ARL's Partnerships in Research Transition (PIRT) program, the above deficiency is addressed by the design of a Stepped-Frequency Radar (SFR) which allows for precise control over the radiated spectrum, while still maintaining an effective ultra-wide bandwidth. The SFR utilizes a frequency synthesizer which can be configured to excise prohibited and interfering frequency bands and also implement frequency-hopping capabilities. The SFR is designed to be a forward-looking ground- penetrating (FLGPR) Radar utilizing a uniform linear array of sixteen (16) Vivaldi notch receive antennas and two (2) Quad-ridge horn transmit antennas. While a preliminary SFR consisting of four (4) receive channels has been designed, this paper describes major improvements to the system, and an analysis of expected system performance. The 4-channel system will be used to validate the SFR design which will eventually be augmented in to the full 16-channel system. The SFR has an operating frequency band which ranges from 300 - 2000 MHz, and a minimum frequency step-size of 1 MHz. The radar system is capable of illuminating range swaths that have maximum extents of 30 to 150 meters (programmable). The transmitter has the ability to produce approximately -2 dBm/MHz average power over the entire operating frequency range. The SFR will be used to determine the practicality of detecting and classifying buried and concealed landmines and IEDs from safe stand-off distances.

Phelan, Brian R.; Sherbondy, Kelly D.; Ranney, Kenneth I.; Narayanan, Ram M.

2014-05-01

145

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems  

SciTech Connect

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

Morey, R M

1998-12-08

146

Design and development of ultra-wideband 3 dB hybrid coupler for Ion cyclotron resonance frequency heating in tokamak  

NASA Astrophysics Data System (ADS)

Design and development of a high power ultra-wideband, 3 dB tandem hybrid coupler is presented and its application in ICRF heating of the tokamak is discussed. In order to achieve the desired frequency band of 38-112 MHz and 200 kW power handling capability, the 3 dB hybrid coupler is developed using two 3-element 8.34 ± 0.2 dB coupled lines sections in tandem. In multi-element coupled lines, junctions are employed for the joining of coupled elements that produce the undesirable reactance called junction discontinuity effect. The effect becomes prominent in the high power multi-element coupled lines for high frequency (HF) and very high frequency(VHF) applications because of larger structural dimensions. Junction discontinuity effect significantly deteriorates coupling and output performance from the theoretical predictions. For the analysis of junction discontinuity effect and its compensation, a theoretical approach has been developed and generalized for n-element coupled lines section. The theory has been applied in the development of the 3 dB hybrid coupler. The fabricated hybrid coupler has been experimentally characterized using vector network analyzer and obtained results are found in good agreement with developed theory.

Yadav, Rana Pratap; Kumar, Sunil; Kulkarni, S. V.

2014-04-01

147

Ultra-broadband indoor optical wireless communication system with multimode fiber.  

PubMed

In this paper we experimentally demonstrate an ultra-broadband indoor full-duplex WDM optical wireless communication system with multimode fiber. The multimode fiber is used because it is employed in most of the already installed in-building fiber distribution networks. Simultaneous error-free (BER<10(-9)) transmission of 4×12.5 Gbps downlink and 800 Mbps uplink has been successfully demonstrated. The experimental results show that, although the use of multimode fiber will induce ~2.4 cm reduction in the maximum error-free beam footprint in the downlink, the bit rate of the uplink can be much higher compared to the system with single-mode fiber. PMID:22555722

Wang, Ke; Nirmalathas, Ampalavanapillai; Lim, Christina; Skafidas, Efstratios

2012-05-01

148

Design and optimization of an ultra wideband and compact microwave antenna for radiometric monitoring of brain temperature.  

PubMed

We present the modeling efforts on antenna design and frequency selection to monitor brain temperature during prolonged surgery using noninvasive microwave radiometry. A tapered log-spiral antenna design is chosen for its wideband characteristics that allow higher power collection from deep brain. Parametric analysis with the software HFSS is used to optimize antenna performance for deep brain temperature sensing. Radiometric antenna efficiency (?) is evaluated in terms of the ratio of power collected from brain to total power received by the antenna. Anatomical information extracted from several adult computed tomography scans is used to establish design parameters for constructing an accurate layered 3-D tissue phantom. This head phantom includes separate brain and scalp regions, with tissue equivalent liquids circulating at independent temperatures on either side of an intact skull. The optimized frequency band is 1.1-1.6 GHz producing an average antenna efficiency of 50.3% from a two turn log-spiral antenna. The entire sensor package is contained in a lightweight and low-profile 2.8 cm diameter by 1.5 cm high assembly that can be held in place over the skin with an electromagnetic interference shielding adhesive patch. The calculated radiometric equivalent brain temperature tracks within 0.4 °C of the measured brain phantom temperature when the brain phantom is lowered 10 °C and then returned to the original temperature (37 °C) over a 4.6-h experiment. The numerical and experimental results demonstrate that the optimized 2.5-cm log-spiral antenna is well suited for the noninvasive radiometric sensing of deep brain temperature. PMID:24759979

Rodrigues, Dario B; Maccarini, Paolo F; Salahi, Sara; Oliveira, Tiago R; Pereira, Pedro J S; Limao-Vieira, Paulo; Snow, Brent W; Reudink, Doug; Stauffer, Paul R

2014-07-01

149

Ultra-low power wireless sensing for long-term structural health monitoring  

NASA Astrophysics Data System (ADS)

Researchers have made significant progress in recent years towards realizing long-term structural health monitoring (SHM) utilizing wireless smart sensor networks (WSSNs). These efforts have focused on improving the performance and robustness of such networks to achieve high quality data acquisition and in-network processing. One of the primary challenges still facing the use of smart sensors for long-term monitoring deployments is their limited power resources. Periodically accessing the sensor nodes to change batteries is not feasible or economical in many deployment cases. While energy harvesting techniques show promise for prolonging unattended network life, low-power design and operation are still critically important. This research presents a new, fully integrated ultra-low power wireless smart sensor node and a flexible base station, both designed for long-term SHM applications. The power consumption of the sensor nodes and base station has been minimized through careful hardware selection and the implementation of power-aware network software, without sacrificing flexibility and functionality.

Bilbao, Argenis; Hoover, Davis; Rice, Jennifer; Chapman, Jamie

2011-04-01

150

Tunable ultra-wideband terahertz filter based on three-dimensional arrays of H-shaped plasmonic crystals  

NASA Astrophysics Data System (ADS)

A face-to-face system of double-layer three-dimensional arrays of H-shaped plasmonic crystals is proposed, and its transmission and filtering properties are investigated in the terahertz regime. Simulation results show that our design has excellent filtering properties. It has an ultra-wide bandgap and passband with steep band-edges, and the transmittance of the passband and the forbidden band are very close to 1 and 0, respectively. As the distance between the two face-to-face plates increases, the resonance frequency exhibits a gradual blueshift from 0.88 THz to 1.30 THz. Therefore, we can dynamically control the bandwidths of bandgap and passband by adding a piezoelectric ceramic plate between the two crystal plates. Furthermore, the dispersion relations of modes and electric field distributions are presented to analyze the generation mechanisms of bandgaps and to explain the location of bandgaps and the frequency shift phenomenon. Due to the fact that our design can provide many resonant modes, the bandwidth of the bandgaps can be greatly broadened. This paper can serve as a valuable reference for the design of terahertz functional devices and three-dimensional terahertz metamaterials.

Yuan, Cai; Xu, Shi-Lin; Yao, Jian-Quan; Zhao, Xiao-Lei; Cao, Xiao-Long; Wu, Liang

2014-01-01

151

Development of ultra-high sensitivity wide-band gap UV-EUV detectors at NASA Goddard Space Flight Center  

NASA Astrophysics Data System (ADS)

Rapid progress in the AlGaN (Eg=3.4-6.2eV), 4H-SiC (Eg=3.2eV) and ZnMgO (Eg=2.8-7.9eV) material systems over the last five years has led to the demonstration of a number of opto-electronic devices. These wide energy band gap devices offer several key advantages for space applications, over conventional Si (Eg=1.1eV) based devices, such as visible-blind detection, high thermal stability, better radiation hardness, high breakdown electric field, high chemical inertness and greater mechanical strength. Furthermore, the shorter cut-off wavelength of these material systems eliminates the need for bulky and expensive optical filtering components mitigating risk and allowing for simpler optical design of instrumentation. In this paper, we report on the development at NASA/Goddard of ultra-sensitive, high quantum efficiency AlGaN and 4H-SiC Schottky barrier UV-EUV photodiodes, 4H-SiC UV single photon avalanche diodes, large format 256x256 AlGaN UV p-i-n photodiode arrays and recent progress in elemental substitution for p-type and enhanced n-type doping of ZnO.

Aslam, S.; Yan, F.; Pugel, D. E.; Franz, D.; Miko, L.; Herrero, F.; Matsumara, M.; Babu, S.; Stahle, C. M.

2005-08-01

152

A Comparative Study of Wireless Protocols: Bluetooth, UWB, ZigBee, and Wi-Fi  

Microsoft Academic Search

Bluetooth (over IEEE 802.15.1), ultra-wideband (UWB, over IEEE 802.15.3), ZigBee (over IEEE 802.15.4), and Wi-Fi (over IEEE 802.11) are four protocol standards for short- range wireless communications with low power consumption. From an application point of view, bluetooth is intended for a cordless mouse, keyboard, and hands-free headset, UWB is oriented to high-bandwidth multimedia links, ZigBee is designed for reliable

Jin-Shyan Lee; Yu-Wei Su; Chung-Chou Shen

2007-01-01

153

Low cost and precise localization in a remote-powered wireless sensor and identification system  

Microsoft Academic Search

A low cost and precise localization system based on a remote-powered UWB-RFID tag is presented for wireless identification, sensing, positioning and tracking. Our contribution is to utilize the Impulse Radio Ultra wideband (IR-UWB) communication in a RFID system. Such as conventional RFIDs, a tag captures energy from the received RF signal transmitted by a reader which also carries data and

Majid Baghaei-Nejad; Li-Rong Zheng

2011-01-01

154

On the Evaluation of Channel Capacity of UWB Indoor Wireless Systems  

Microsoft Academic Search

This paper discusses the channel capacity of multiantenna ultra-wideband (UWB) indoor wireless systems. It is shown first that for both single-input single-output (SISO) and multiple-input multiple-output (MIMO) cases, when the transmit SNR is lower than some value, say -20 dB, using optimal power spectrum allocation (OPSA) at the transmitter side can increase the reliable transmission rate considerably compared to the

Feng Zheng; Thomas Kaiser

2008-01-01

155

An Efficient Supply Modulator for Linear Wideband RF Power Amplifiers  

E-print Network

of a class A Power amplifier in wideband wireless standards like WiMax is improved by dynamically controlling the bias current and supply voltage of the PA. An efficient supply modulator based on a switching regulator architecture is proposed...

Turkson, Richard

2011-10-21

156

SWIFT: A Narrowband-Friendly Cognitive Wideband Network  

E-print Network

Wideband technologies in the unlicensed spectrum can satisfy the ever-increasing demands for wireless bandwidth created by emerging rich media applications. The key challenge for such systems, however, is to allow narrowband ...

Sodini, Charles

2008-08-17

157

Ultra-wideband electronics, design methods, algorithms, and systems for dielectric spectroscopy of isolated B16 tumor cells in liquid medium  

NASA Astrophysics Data System (ADS)

Quantifying and characterizing isolated tumor cells (ITCs) is of interest in surgical pathology and cytology for its potential to provide data for cancer staging, classification, and treatment. Although the independent prognostic significance of circulating ITCs has not been proven, their presence is gaining clinical relevance as an indicator. However, researchers have not established an optimal method for detecting ITCs. Consequently, this Ph.D. dissertation is concerned with the development and evaluation of dielectric spectroscopy as a low-cost method for cell characterization and quantification. In support of this goal, ultra-wideband (UWB), microwave pulse generator circuits, coaxial transmission line fixtures, permittivity extraction algorithms, and dielectric spectroscopy measurement systems were developed for evaluating the capacity to quantify B16-F10 tumor cells in suspension. First, this research addressed challenges in developing tunable UWB circuits for pulse generation. In time-domain dielectric spectroscopy, a tunable UWB pulse generator facilitates exploration of microscopic dielectric mechanisms, which contribute to dispersion characteristics. Conventional approaches to tunable pulse generator design have resulted in complex circuit topologies and unsymmetrical waveform morphologies. In this research, a new design approach for low-complexity, tunable, sub-nanosecond and UWB pulse generator was developed. This approach was applied to the development of a novel generator that produces symmetrical waveforms (patent pending 60/597,746). Next, this research addressed problems with transmission-reflection (T/R) measurement of cell suspensions. In T/R measurement, coaxial transmission line fixtures have historically required an elaborate sample holder for containing liquids, resulting in high cost and complexity. Furthermore, the algorithms used to extract T/R dielectric properties have suffered from myriad problems including local minima and halfwavelength resonance. In this dissertation, a simple coaxial transmission line fixture for holding liquids by dispensing with the air-core assumption inherent in previous designs was developed (patent pending 60/916,042). In addition, a genetic algorithm was applied towards extracting dielectric properties from measurement data to circumvent problems of local minima and half wavelength resonance. Finally, in this research the capacity for using dielectric properties to quantify isolated B16-F10 tumor cells in McCoy's liquid medium was investigated. In so doing, the utility of the Maxwell-Wagner mixture formula for cell quantification was demonstrated by measuring distinct dielectric properties for differing volumes of cell suspensions using frequency- and time-domain dielectric spectroscopy.

Maxwell, Erick N.

158

SECURE WIRELESS COMMUNICATIONS: SECRET KEYS THROUGH MULTIPATH Akbar Sayeed  

E-print Network

, quan- tization, wideband transceivers, energy minimization 1. INTRODUCTION Secure wirelessSECURE WIRELESS COMMUNICATIONS: SECRET KEYS THROUGH MULTIPATH Akbar Sayeed and Adrian Perrig University of Wisconsin-Madison Carnegie Mellon University ABSTRACT Secure wireless communications

Sayeed, Akbar M.

159

Picoradics for wireless sensor networks: the next challenge in ultra-low-power design  

Microsoft Academic Search

Summary form only given. An untapped opportunity in the realm of wireless data lies in low data-rate (<10 kb\\/s) low-cost wireless transceivers, assembled into distributed networks of sensor and actuator nodes. This enables applications such as smart buildings and highways, environment monitoring, user interfaces, entertainment, factory automation, and robotics While the aggregate system processes large amounts of data, individual nodes

Jan M. Rabaey; Josie Ammer; Tufan Karalar; Suetfei Li; Brian Otis; Mike Sheets; Tim Tuan

2002-01-01

160

Design of indoor communication infrastructure for ultra-high capacity next generation wireless services  

E-print Network

, such as in wireless systems, Maxwell’s equations provide extremely accurate descriptions of propagation of electromagnetic radiation as waves. In the simplest possible case when radiation is transferred from a single transmitting antenna to a single receiving antenna... [12]. 3 1.1.2 Principles of wireless The most accurate model for predicting the behaviour of electromagnetic phenomena is that of quantum electrodynamics. However, for behaviour over macroscopic distances using large number of photons...

Gordon, George S. D.

2013-11-12

161

VIZOR: Virtually zero margin adaptive RF for ultra low power wireless communication  

Microsoft Academic Search

Modern wireless transceiver systems are often overdesigned to meet the requirements of low bit error rate values at high data rates under worst-case channel operating conditions (interference, noise, multi-path effects). This results in circuits being designed with ldquosufficientrdquo margins leading to lower efficiency and high power consumption. In this paper, we develop an adaptive power management strategy for RF systems

Rajarajan Senguttuvan; Shreyas Sen; Abhijit Chatterjee

2007-01-01

162

Design considerations on ultra-low-power wireless transmitters for wearable medical devices  

Microsoft Academic Search

A wireless transmitter for wearable bio-sensing applications must fulfill very specialized requirements. It has been estimated that for truly wearable systems it must operate with an average power consumption of less than 140 ?W. The alternatives, pitfalls, and realistic performance of robust, low power signal transmission will be addressed.

Danilo Manstretta

2010-01-01

163

An ultra low power ADC for wireless micro-sensor applications  

E-print Network

Autonomous micro-sensor nodes rely on low-power circuits to enable energy harvesting as a means of sustaining long-term, maintenance free operation. This work pursues the design of an ultra low-power analog-to-digital ...

Verma, Naveen

2005-01-01

164

Ultra-low power Wi-Fi tag for wireless sensing  

Microsoft Academic Search

G2 microsystems of Campbell, California, USA, released in 2007 the first ever ultra-low power Wi-Fi System on a Chip (SoC) named G2C501. This SoC includes a 32-bit CPU, crypto accelerator, real-time clock and a versatile sensor interface that can serve as a standalone host subsystem. The G2C501 goes beyond todaypsilas basic radio frequency identification (RFID) technology to offer intelligent tracking

Silviu Folea; Marius Ghercioiu

2008-01-01

165

Wireless wire-the 60 GHz ultra-low power radio system  

Microsoft Academic Search

This article presents basic issues regarding design and development of a 60 GHz ultra-low power radio system for ambient intelligence (AmI) applications. It demonstrates the validity of choosing the 60 GHz frequency band to design low power radios by a mathematical model, and proposes an overview of a cross-layer optimization flow to minimize power dissipation. Moreover, a completed RF front-end

Xia Li; Peter Baltus; Dusan Milosevic; Wei Deng; Paul van Zeijl; Neil Bird; Arthur van Roermund

2009-01-01

166

Wireless connections within spacecrafts to replace wired interface buses  

NASA Astrophysics Data System (ADS)

This paper describes measurement and characterization of radio propagation and transmission - particularly of ultra wideband (UWB) signals - within spacecrafts with a view to partly replacing on-board data buses with wireless connections. Adaption of wireless technologies within spacecraft could contribute to reduction of cable weight and resulting launching costs, and more reliable connections at rotary, moving, and sliding joints. This paper presents measurements and characteristics of radio propagation and transmission and addresses the effects of apertures perforated on the outer surface of satellites on the UWB propagation and transmission for low- and high-band UWB within a shield box. Channel responses, spatial distributions of UWB and narrowband propagation gains, delay spreads, and throughputs were derived from measurements. On the effects of apertures, the larger total area of apertures resulted in lower UWB propagation gains, shorter delay spreads, and (slightly) higher link throughput. The propagation study was followed up with experimental evaluation of UWB link throughput within a simulated spacecraft. Commercially off-the-shelf UWB devices were used in the experiments of ultra wideband technology to facilitate a high data rate (e.g. maximum of 400 Mb/s per node attained with SpaceWire, equaling the standards of a wired onboard data bus) and to reduce the fading margin.

Hamada, S.; Tomiki, A.; Toda, T.; Kobayashi, T.

167

A Wavelet Approach to Wideband Spectrum Sensing for Cognitive Radios  

Microsoft Academic Search

In cognitive radio networks, the first cognitive task preceding any form of dynamic spectrum management is the sensing and identification of spectrum holes in wireless environments. This paper develops a wavelet approach to efficient spectrum sensing of wideband channels. The signal spectrum over a wide frequency band is decomposed into elementary building blocks of subbands that are well characterized by

Zhi Tian; Georgios B. Giannakis

2006-01-01

168

Wideband RF-MEMS shunt switches with high reliability for microwave and millimeter wave applications  

Microsoft Academic Search

An ultra wideband RF-MEMS shunt switch with a PZT\\/HfO2 stacked insulator has been developed for microwave and millimeter wave applications. The both of the conjunctive dielectric constant, 80, of PZT(r=800)\\/HfO2(r=20) stack layer and a match circuit contribute to high isolation of -30 dB at ultra wideband from 1 GHz to 50 GHz frequencies. The increase of the trap density in

K. Onodera; Yi Zhang; R. Maeda

2005-01-01

169

A low complexity wireless microbial fuel cell monitor using piezoresistive sensors and impulse-radio ultra-wide-band  

NASA Astrophysics Data System (ADS)

Microbial Fuel Cells (MFCs) are energy sources which generate electrical charge thanks to bacteria metabolism. Although functionally similar to chemical fuel cells (both including reactants and two electrodes, and anode and cathode), they have substantial advantages, e.g. 1) operation at ambient temperature and pressure; 2) use of neutral electrolytes and avoidance of expensive catalysts (e.g. platinum); 3) operation using organic wastes. An MFC can be effectively used in environments where ubiquitous networking requires the wireless monitoring of energy sources. We then report on a simple monitoring system for MFC comprising an ultra-low-power Impulse-Radio Ultra-Wide-Band Transmitter (TX) operating in the low 0-960MHz band and a nanostructured piezoresistive pressure sensor connected to a discrete component digital read-out circuit. The sensor comprises an insulating matrix of polydimethylsiloxane and nanostructured multi-branched copper microparticles as conductive filler. Applied mechanical stress induces a sample deformation that modulates the mean distance between particles, i.e. the current flow. The read-out circuit encodes pressure as a pulse rate variation, with an absolute sensitivity to the generated MFC voltage. Pulses with variable repetition frequency can encode battery health: the pressure sensor can be directly connected to the cells membrane to read excessive pressure. A prototype system comprises two MFCs connected in series to power both the UWB transmitter which consumes 40?W and the read-out circuit. The two MFC generate an open circuit voltage of 1.0+/-0.1V. Each MFC prototype has a total volume of 0.34L and is formed by two circular Poly(methyl methacrylate) (PMMA) chambers (anode and cathode) separated by a cation exchange membrane. The paper reports on the prototype and measurements towards a final solution which embeds all functionalities within a MFC cell. Our solution is conceived to provide energy sources integrating energy management and health monitoring capabilities to sensor nodes which are not connected to the energy grid.

Crepaldi, M.; Chiolerio, A.; Tommasi, T.; Hidalgo, D.; Canavese, G.; Stassi, S.; Demarchi, D.; Pirri, F. C.

2013-05-01

170

Wideband active antenna cancellation  

E-print Network

There exists a simultaneous transmit and receive antenna system where the transmitted signal is creating wideband interference of the receiver. To resolve this interference problem, the isolation between the transmit antenna ...

Adaniya, Hana L

2008-01-01

171

ULTRA WIDEBAND FRACTAL MICROSTRIP ANTENNA DESIGN  

Microsoft Academic Search

Abstract—Newfractal geometry for microstrip antennas is presented in this paper. This fractal structure is implemented on hexagonal and,several iteration is applied on initial shape.,This antenna has lowprofile, lightw eight and is easy to be fabricated and has successfully demonstrated multiband and broadband characteristics. The simulated results showthat proposed antenna has very good performance in impedance bandwidth and radiation pattern.

Abolfazl Azari; Javad Rowhani

2008-01-01

172

Thin Wideband Radar Absorbers  

Microsoft Academic Search

A procedure for the optimal design of thin wideband radar absorbers is presented. The resulting absorbers are implemented by printing a frequency selective surface on a lossy perforated substrate. A binary hill climbing optimization scheme with random restart is used to find optimal solutions. The method of moments in conjunction with the transmission line method is used to calculate the

Arya Fallahi; Alireza Yahaghi; Hans-Rudolf Benedickter; Habibollah Abiri; Mahmoud Shahabadi; Christian Hafner

2010-01-01

173

Schedule-based sequential localization in asynchronous wireless networks  

NASA Astrophysics Data System (ADS)

In this paper, we consider the schedule-based network localization concept, which does not require synchronization among nodes and does not involve communication overhead. The concept makes use of a common transmission sequence, which enables each node to perform self-localization and to localize the entire network, based on noisy propagation-time measurements. We formulate the schedule-based localization problem as an estimation problem in a Bayesian framework. This provides robustness with respect to uncertainty in such system parameters as anchor locations and timing devices. Moreover, we derive a sequential approximate maximum a posteriori (AMAP) estimator. The estimator is fully decentralized and copes with varying noise levels. By studying the fundamental constraints given by the considered measurement model, we provide a system design methodology which enables a scalable solution. Finally, we evaluate the performance of the proposed AMAP estimator by numerical simulations emulating an impulse-radio ultra-wideband (IR-UWB) wireless network.

Zachariah, Dave; Angelis, Alessio De; Dwivedi, Satyam; Händel, Peter

2014-12-01

174

Tunable filters using wideband elastic resonators.  

PubMed

Currently, an ultra-wideband resonator is greatly needed to realize a tunable filter with a wide tunable range, because mobile phones with multiple bands and cognitive radio systems require such tunable filters to simplify their circuits. Although tunable filters have been studied using SAW resonators, their tunable range was insufficient for the filters even when wideband SAW resonators with a bandwidth of 17% were used. Therefore, the fabrication of wider-bandwidth resonators has been attempted with the goal of realizing tunable filters with wide tunable ranges. In this study, an SH0- mode plate wave resonator in a 27.5°YX-LiNbO3 plate with an ultra-wide bandwidth of 29.1%, a high impedance ratio of 98 dB, and a high Q (Q(r) = 700 and Q(a) = 720) was realized. Two types of tunable filters were constructed using such SH0-mode resonators and capacitors. As a result, tunable ranges (bands) of 13% to 19% were obtained. The possibility of applying the SH0-mode resonator in the high-frequency gigahertz range is discussed. PMID:24081261

Kadota, Michio; Ogami, Takashi; Kimura, Tetsuya; Daimon, Katsuya

2013-10-01

175

Centralized route recovery based on multi-hop wakeup time estimation for wireless sensor networks with ultra low duty cycles  

E-print Network

Centralized route recovery based on multi-hop wakeup time estimation for wireless sensor networks packet flooding for route recovery and solves the high energy consumption problem caused by each node is the sum of the wakeup period and the sleep period. However, for existing routing protocols, it is very

Bahk, Saewoong

176

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care  

NASA Astrophysics Data System (ADS)

Continuous monitoring of internal physiological parameters is essential for critical care patients, but currently can only be practically achieved via tethered solutions. Here we report a wireless, real-time pressure monitoring system with passive, flexible, millimetre-scale sensors, scaled down to unprecedented dimensions of 1 × 1 × 0.1 cubic millimeters. This level of dimensional scaling is enabled by novel sensor design and detection schemes, which overcome the operating frequency limits of traditional strategies and exhibit insensitivity to lossy tissue environments. We demonstrate the use of this system to capture human pulse waveforms wirelessly in real time as well as to monitor in vivo intracranial pressure continuously in proof-of-concept mice studies using sensors down to 2.5 × 2.5 × 0.1 cubic millimeters. We further introduce printable wireless sensor arrays and show their use in real-time spatial pressure mapping. Looking forward, this technology has broader applications in continuous wireless monitoring of multiple physiological parameters for biomedical research and patient care.

Chen, Lisa Y.; Tee, Benjamin C.-K.; Chortos, Alex L.; Schwartz, Gregor; Tse, Victor; J. Lipomi, Darren; Wong, H.-S. Philip; McConnell, Michael V.; Bao, Zhenan

2014-10-01

177

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care.  

PubMed

Continuous monitoring of internal physiological parameters is essential for critical care patients, but currently can only be practically achieved via tethered solutions. Here we report a wireless, real-time pressure monitoring system with passive, flexible, millimetre-scale sensors, scaled down to unprecedented dimensions of 1 × 1 × 0.1 cubic millimeters. This level of dimensional scaling is enabled by novel sensor design and detection schemes, which overcome the operating frequency limits of traditional strategies and exhibit insensitivity to lossy tissue environments. We demonstrate the use of this system to capture human pulse waveforms wirelessly in real time as well as to monitor in vivo intracranial pressure continuously in proof-of-concept mice studies using sensors down to 2.5 × 2.5 × 0.1 cubic millimeters. We further introduce printable wireless sensor arrays and show their use in real-time spatial pressure mapping. Looking forward, this technology has broader applications in continuous wireless monitoring of multiple physiological parameters for biomedical research and patient care. PMID:25284074

Chen, Lisa Y; Tee, Benjamin C-K; Chortos, Alex L; Schwartz, Gregor; Tse, Victor; Lipomi, Darren J; Wong, H-S Philip; McConnell, Michael V; Bao, Zhenan

2014-01-01

178

EcoCast: Interactive, object-oriented macroprogramming for networks of ultra-compact wireless sensor nodes  

Microsoft Academic Search

EcoCast is an execution framework for macroprogramming of wireless sensor networks. Users access sensor nodes as dynamic objects in Python by invoking methods on them without being concerned with network protocols, and type marshalling and demarshalling ensure proper data access. EcoCast extends Python’s functional programming primitives map(), reduce(), and filter() to macroprogramming with several synchrony semantics and job-control options. EcoCast

Yi-Hsuan Tu; Yen-Chiu Li; Ting-Chou Chien; Pai H. Chou

2011-01-01

179

Wideband Fractal Vertical Patch Antenna  

Microsoft Academic Search

A wideband vertical patch antenna (VPA) is depicted, which is devised from fractal antenna technology. By using a dual-Koch loop structure, a wideband VPA with 42% bandwidth and 8 dBi gain at the center frequency is designed and tested. Symmetrical broadside patterns are obtained at the passband.

T. P. Wong; Carmen K. L. Lau; Kwai-Man Luk; Kai-Fong Lee

2007-01-01

180

Reconfigurable wideband to narrowband antenna using tunable EBG structure  

NASA Astrophysics Data System (ADS)

In this paper, frequency reconfigurable electromagnetic band gap (EBG) structure that integrates with a wideband antenna is proposed. The EBG structure consists of a circular patch shorted to the ground plane and a secondary circular patch connected to the circular patch. Switches are positioned between the via and the ground plane and by controlling the state of the switch, the band-stop operation of the EBG can be activated or deactivated. In order to control the single and dual band-stop operation, another switch is place between the circular patch and the secondary circular patch. The EBG structure is then placed underneath the feed line of a wideband antenna. The antenna is capable of reconfiguring to three different frequency bands. The proposed antenna has the potential to provide useful features for the wireless communication applications.

Majid, H. A.; Rahim, M. K. A.; Hamid, M. R.; Ayop, O.

2014-08-01

181

AWACS: ATM Wireless Access System - potential candidate for European HIPERLINK standard  

Microsoft Academic Search

Wireless ATM is receiving a significant attention as a solution for wireless access. The integration of wireless access and ATM is an essential requirement for the future of telecommunications so that emerging wideband services which embody multimedia applications can be made transparently available to mobile terminals. There are many ongoing activities within the European ACTS program (Advanced Communications Technologies and

C. Evci; A. De Hoz; R. Rheinschmitt; M. Araki; Mark A. Beach; Andrew R. Nix; P. Hafezi; Y. Sun; Sergio Barberis; E. Gaiani; B. Melis; G. Romano; Valerio Palestini; M. Tolonen; H. Hakalahti

1999-01-01

182

Wideband optical storage  

NASA Technical Reports Server (NTRS)

This paper has five purposes. First, to focus upon the key relationships that bound the technology choices for large, archival, digital storage devices; second, to identify the motivations for selecting the optical technology for a petabit-exabit level storage system (10 to the 15th to 10 to the 18th bits); third, to present a generic example and a specific implementation of a terabit-level optical storage device; fourth, to characterize the global design space constraints that will allow one to build a technology-limited optical store; and fifth, to sketch the outline of the BYTERON concept, a wideband 10 to the 16th to 10 to the 17th bit optical store concept and contrast its performance to that of an optical store that is in operation today

Heard, H. G.

1979-01-01

183

Ultra-short pulse generator  

SciTech Connect

An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shockwave diode, which increases and sharpens the pulse even more.

McEwan, Thomas E. (Livermore, CA)

1993-01-01

184

Ultra-short pulse generator  

DOEpatents

An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shock wave diode, which increases and sharpens the pulse even more. 5 figures.

McEwan, T.E.

1993-12-28

185

Wideband waveguide polarizer development for SETI  

NASA Technical Reports Server (NTRS)

A wideband polarizer for the Deep Space Network (DSN) 34 meter beam waveguide antenna is needed for the Search for Extraterrestrial Intelligence (SETI) project. The results of a computer analysis of a wideband polarizer are presented.

Lee, P.; Stanton, P.

1991-01-01

186

Wideband transhorizon channel characterization  

NASA Astrophysics Data System (ADS)

The paper describes a 31.25 MHz bandwidth wideband channel sounder used to characterize a transhorizon path over the English Channel (La Manche) at 11.64 GHz. The measurements were done continuously for a period of 8 months (June 5, 1996, to January 5, 1997), capturing 515 Mb of data each day. A nonlinear regression technique, singular value decomposition prony (SVD-P), was used to estimate the channel impulse response from the measured transfer function. The received signal levels obtained together with their dynamic signatures were used to categorize the mechanisms into three broad groups: ducting, strong enhancements, and troposcatter. The statistical analysis carried out gave strong correlation between signal levels, delay spread, coherence bandwidth, and Doppler spread. The results also help to highlight the limitation of traditional channel characterization parameters such as delay spread. The investigation has also revealed the potential and propagation conditions of an over the sea transhorizon path as a high-data-rate communication channel. The research has qualified and quantified the interference potential in spectrum reuse and the frequency decorrelation probabilities to combat it.

Ndzi, David; Austin, John; Vilar, Enric

2001-09-01

187

A Wideband Spiral Antenna for Ingestible Capsule Endoscope Systems: Experimental Results in a Human Phantom and a Pig  

Microsoft Academic Search

This paper presents the design of a wideband spiral antenna for ingestible capsule endoscope systems and a compari- son between the experimental results in a human phantom and a pig under general anesthesia. As wireless capsule endoscope sys- tems transmit real-time internal biological image data at a high resolution to external receivers and because they operate in the human body,

Sang Heun Lee; Jaebok Lee; Young Joong Yoon; Changyul Cheon; Kihyun Kim; Sangwook Nam

2011-01-01

188

Communication for wideband fading channels : on theory and practice  

E-print Network

This dissertation investigates some information theoretic aspects of communication over wideband fading channels and their applicability to design of signaling schemes approaching the wideband capacity limit. This work ...

Luo, Cheng, Ph. D. Massachusetts Institute of Technology

2006-01-01

189

Study of a wideband probe  

NASA Technical Reports Server (NTRS)

The design of an experiment to measure communication characteristics of wideband satellite-to-ground links is reported. Of special concern are the effects of rainstorms and atmospheric turbulence on path attenuation and phase fluctuation. Multi-tone and pulse probing are considered. A multi-tone technique which is a modification of ATS-5 and ATS-F hardware is recommended. Data extraction and data processing techniques and key hardware requirements for the experiment are reviewed.

Alexander, P., Jr.; Salwen, H.

1972-01-01

190

Super wideband fractal antenna design  

Microsoft Academic Search

Fractals have very unique properties, therefore in recent years, antenna designers use fractal geometry in multi-band and broad-band antennas designing. In this paper, I have achieved to a 40 GHz super wideband antenna with applying a fractal geometry to a wire square loop antenna and choosing appropriate size and location for feeding. Modelling and simulation is performed via SuperNEC electromagnetic

Abolfazl Azari

2009-01-01

191

MISO CDMA transmission with simplified receiver for wireless communication handsets  

Microsoft Academic Search

The next-generation wireless personal and mobile communication systems are expected to accommodate not only high-quality voice services, but also a broad range of other multirate services. Of the various multiaccess techniques, wide-band code-division multiple access (CDMA) has been regarded as an important part of the third-generation wireless communication systems because of its high frequency utilization efficiency and suitability for handling

Ruly Lai-U Choi; Khaled Ben Letaief; Ross D. Murch

2001-01-01

192

Wireless network system based multi-non-invasive sensors for smart home  

NASA Astrophysics Data System (ADS)

There are several techniques that have been implemented for smart homes usage; however, most of these techniques are limited to a few sensors. Many of these methods neither meet the needs of the user nor are cost-effective. This thesis discusses the design, development, and implementation of a wireless network system, based on multi-non-invasive sensors for smart home environments. This system has the potential to be used as a means to accurately, and remotely, determine the activities of daily living by continuously monitoring relatively simple parameters that measure the interaction between users and their surrounding environment. We designed and developed a prototype system to meet the specific needs of the elderly population. Unlike audio-video based health monitoring systems (which have associated problems such as the encroachment of privacy), the developed system's distinct features ensure privacy and are almost invisible to the occupants, thus increasing the acceptance levels of this system in household environments. The developed system not only achieved high levels of accuracy, but it is also portable, easy to use, cost-effective, and requires low data rates and less power compared to other wireless devices such as Wi-Fi, Bluetooth, wireless USB, Ultra wideband (UWB), or Infrared (IR) wireless. Field testing of the prototype system was conducted at different locations inside and outside of the Minto Building (Centre for Advanced Studies in Engineering at Carleton University) as well as other locations, such as the washroom, kitchen, and living room of a prototype apartment. The main goal of the testing was to determine the range of the prototype system and the functionality of each sensor in different environments. After it was verified that the system operated well in all of the tested environments, data were then collected at the different locations for analysis and interpretation in order to identify the activities of daily living of an occupant.

Issa Ahmed, Rudhwan

193

Constrained state estimation for individual localization in wireless body sensor networks.  

PubMed

Wireless body sensor networks based on ultra-wideband radio have recently received much research attention due to its wide applications in health-care, security, sports and entertainment. Accurate localization is a fundamental problem to realize the development of effective location-aware applications above. In this paper the problem of constrained state estimation for individual localization in wireless body sensor networks is addressed. Priori knowledge about geometry among the on-body nodes as additional constraint is incorporated into the traditional filtering system. The analytical expression of state estimation with linear constraint to exploit the additional information is derived. Furthermore, for nonlinear constraint, first-order and second-order linearizations via Taylor series expansion are proposed to transform the nonlinear constraint to the linear case. Examples between the first-order and second-order nonlinear constrained filters based on interacting multiple model extended kalman filter (IMM-EKF) show that the second-order solution for higher order nonlinearity as present in this paper outperforms the first-order solution, and constrained IMM-EKF obtains superior estimation than IMM-EKF without constraint. Another brownian motion individual localization example also illustrates the effectiveness of constrained nonlinear iterative least square (NILS), which gets better filtering performance than NILS without constraint. PMID:25390408

Feng, Xiaoxue; Snoussi, Hichem; Liang, Yan; Jiao, Lianmeng

2014-01-01

194

Fundamental limits of wideband localization  

E-print Network

Location-awareness is essential for many wireless network applications. However, determining nodes' positions precisely is a challenging task, especially in harsh multipath propagation environments. To address this problem, ...

Shen, Yuan, Ph. D. Massachusetts Institute of Technology

2008-01-01

195

A wideband EMP test system  

NASA Astrophysics Data System (ADS)

A wideband EMP tester consisting of a high voltage modulator, transmission line, high voltage peaking switch, and a TEM test cell has been developed that delivers repetitive high frequency EMP pulses to an RF-sealed double-test volume of about 1 cu ft. The pulse shape is rectangular, has a duration of 4 ns and a risetime of 120 ps. The system can be operated at pulse repetition rates up to 1500 Hz and electric field levels up to 125 kV/m. Both voltage and pulse rate are continuously adjustable over these ranges may be operated in any combination.

Rohwein, G. J.; Aurand, J. F.; Frost, C. A.; Roose, L. D.; Babcock, S. R.

1994-08-01

196

Analysis and design of a wideband dual-polarized antenna based on the principle of Huygens' source  

NASA Astrophysics Data System (ADS)

Analysis and designs of wideband dual-polarized antennas for mobile wireless communication systems are presented. The concept for Huygens' sources, which are combinations of electric and magnetic dipoles, is used. As a result a wideband unidirectional antenna, which consists of a planar dipole and a slot, is selected for the antenna element. This study aims at designing a dually polarized antenna with wideband performance. The first part of the study discusses the performance of the linearly polarized antenna element at 2.5 GHz. Several design parameters associated with the antenna element are addressed. To improve the performance and increase the bandwidth, a twin-fed hook-shaped probe feeding technique is applied. Prototype antennas are fabricated and tested, and good agreement between the simulated and measured results is obtained. The second part of this study is extended to design the wideband dual-polarized patch antenna. Problems associated with the practical implementation of the dual-polarized antenna in printed form are discussed. The wideband performance of the present antenna is examined by shielding the dielectric substrate from the radiating region. The proposed antenna is fabricated and tested. In addition, a metallic side wall is adopted for suppressing the back radiation. The study for designing a possible candidate for a novel dual-polarized antenna by embedding an electromagnetic bandgap (EBG) structure is investigated. Analysis for unit-cells of mushroom-like and wideband uniplanar EBG structures is performed, and simple monopoles are used for exciting the EBG embedded antenna. The presented antennas find many possible applications in many recent wireless communication systems like 3G, 3GPP Long Term Evolution (LTE), 4G, Wi-MAX, and Wi-Bro.

Seo, Hyukjun

197

Wireless sensor networks and environmental monitoring applications  

E-print Network

Radio: 4kbps, 180m Sensors: Light and accelerometer Energy: Solar powered Golem and deputy dust 16mm3-aided medicine Data processing in wireless sensor networks Facilities: Cluster of 16 computers 30 ultra low power wireless sensors Lego robotics lab (10 Mindstorms kits) More to come... (mobile robot, Mindstorms NXT kits

Le Borgne, Yann-Aël

198

Indoor channel characterisation measurements with directional antennas for future high frequency ATM wireless access systems  

Microsoft Academic Search

This paper presents a selection of wideband channel sounding measurements performed as part of the ACTS AWACS (ATM Wireless Access Communications System) project. The results were obtained for two different indoor operating environments (mainly in line-of-sight conditions) at a carrier frequency of 19.37 GHz. The paper discusses the configuration of the wideband channel sounder and its connection to the prototype

Y. Sun; P. Hafezi; A. Nix; M. Beach

1997-01-01

199

Ultra-wideband WDM transmission using cascaded chirped fiber gratings  

Microsoft Academic Search

We demonstrate 32 channel WDM transmission at a per-channel rate of 10 Gb\\/s over 375 km (five amplified fiber spans) of conventional fiber. Chirped-fiber-grating modules provide dispersion compensation over an 18-nm bandwidth, and a swept-frequency measurement confirms continuous good performance across the entire band

L. D. Garrett; A. H. Gnauck; R. W. Tkach; B. Agogliati; L. Arcangeli; D. Scarano; V. Gusmeroli; C. Tosetti; G. Di Maio; F. Forghieri

1999-01-01

200

MURI Research Review Short-Range Ultra-Wideband Systems  

E-print Network

University of Massachusetts: Dave Pozar, Dan Schaubert, Dennis Goeckel Wednesday, August 20, 2003 Old Town Simulation of UWB Antennas and Circuits -- Schaubert UWB Link Budgets -- Pozar Antennas for UWB -- Pozar Optimal Waveform Studies -- Pozar UWB Synthesizer Project -- Scholtz/Namgoong/Pozar 12:00 PM: Lunch 1

Southern California, University of

201

Ultra wideband antenna array processing under spatial aliasing  

E-print Network

in Vm;l, which is centered at ! = ?2!l. Hence, Um;l(!), the spectrum of the flltered signal vm;l(t), would be: Um;l(!) = Hm;l(! +!l)Sl(!)e?j(!+!l)?m +Emf(! +!l) ; (2.12) in which Emf(!+!l) is the noise component after passing through the demodulator.... Under a quite general scenario, (to be discussed in the sequel), we can approximate (2.12) by the following equation: Um;l(!) ? Hm(!l)Sl(!)e?j!l?m +Emf(! +!l) ; (2.13) which assumes the time domain equivalent expression: um(t) = H(!l)sl(t)e?j!l?m +emf...

Shapoury, Alireza

2009-05-15

202

Signal Generation for FMCW Ultra-Wideband Radar  

E-print Network

One of the greatest concerns facing the planet earth today is global warming. Globally the temperatures have risen and this has caused rise in sea level. Since a large percentage of the population lives near the coast sea ...

Patel, Aqsa Ejaz

2009-01-01

203

75 FR 62476 - Ultra-Wideband Transmission Systems  

Federal Register 2010, 2011, 2012, 2013

...potential for interference to C-band fixed satellite and cellular operations. Background 2. On February 14, 2002, the Commission...Commission stated that these results are consistent with the theory, as expressed by NTIA, that RMS measured emission...

2010-10-12

204

Reconnaissance with ultra wideband UHF synthetic aperture radar  

Microsoft Academic Search

The author addresses the problem of detecting and identifying stationary and moving targets with foliage penetrating UHF synthetic aperture radar (SAR). The role of a target's coherent SAR signature, which varies with the radar's frequency and aspect angle, in forming the Fourier space of the SAR signal is analyzed. The resultant relationship is the basis of an algorithm which, after

MEHRDAD SOUMEKH

1995-01-01

205

Performance of Ultra-Wideband Correlator Receiver Using Gaussian Monocycles  

E-print Network

to be the most competitive techniques for indoor WLAN or WPAN communications [1] [2]. TH-UWB can be regarded the signal's low duty cycle and PPM-TH modulation method, and is exhibited by the autocorrelation function codes, but not the shaping pulse, that determines the performance. Due to their effective simultaneous

Abhayapala, Thushara D.

206

Simulation Study of Ultra-Wideband Communication System Tefera Tibebe  

E-print Network

in frequency and thus their immunity to multipath effects have attracted growing interest as a viable candidate for short range high speed indoor radio communication services. In section 2, the technology basics of UWB, Gaussian mono-pulse & poly-cycle, their properties in the Time & Frequency domains UWB signals are produced

Haddadi, Hamed

207

A novel wideband gyrotron travelling wave amplifier  

E-print Network

We present the design and the experimental results of a novel wideband quasioptical Gyrotron Traveling Wave Tube (gyro-TWT) amplifier and the first Vacuum Electron Device (VED) with a Photonic Band Gap (PBG) structure. The ...

Sirigiri, Jagadishwar R. (Jagadishwar Rao), 1973-

2003-01-01

208

Wideband integrated voice/data technology  

NASA Astrophysics Data System (ADS)

This report describes work performed on the Wideband Integrated Voice/Data Technology Program sponsored by the Information Processing Techniques Office of the Defense Advanced Research Projects Agency during the period 1 April through 30 September 1984.

Weinstein, C. J.

1984-09-01

209

Wideband integrated voice/data technology  

NASA Astrophysics Data System (ADS)

This report describes work performed on the Wideband Integrated Voice/Data Technology Program sponsored by the Information Processing Techniques Office of the Defense Advanced Research Projects Agency during the period 1 October 1983 through 31 March 1984.

Weinstein, C. J.

1984-03-01

210

A wideband software reconfigurable modem  

NASA Astrophysics Data System (ADS)

A wideband modem is described which provides signal processing capability for four Lx-band signals employing QPSK, MSK and PPM waveforms and employs a software reconfigurable architecture for maximum system flexibility and graceful degradation. The current processor uses a 2901 and two 8086 microprocessors per channel and performs acquisition, tracking, and data demodulation for JITDS, GPS, IFF and TACAN systems. The next generation processor will be implemented using a VHSIC chip set employing a programmable complex array vector processor module, a GP computer module, customized gate array modules, and a digital array correlator. This integrated processor has application to a wide number of diverse system waveforms, and will bring the benefits of VHSIC technology insertion into avionic antijam communications systems.

Turner, J. H., Jr.; Vickers, H.

211

Low Power Filtering Techniques for Wideband and Wireless Applications  

E-print Network

architecture. The prototype fabricated in standard 0.35um CMOS process shows -41dB of IM3 for 250mV peak to peak swing with 8.6mW/pole of power dissipation. Also, an LC prototype implemented using similar architecture is discussed in brief. It is shown that...

Gambhir, Manisha

2010-10-12

212

A wideband all-optical WDM network  

Microsoft Academic Search

We describe some of the results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks in developing architectures, technology components, and applications for the realization of scaleable, wideband, and transparent optical wavelength-division multiplexing (WDM) networks. Our architecture addresses all-optical transport over the wide, metropolitan, and local areas. It utilizes wavelength partitioning, routing, and active multiwavelength cross-connect

I. P. Kaminow; C. R. Doerr; C. Dragone; T. Koch; U. Koren; A. A. M. Saleh; A. J. Kirby; C. M. Ozveren; B. Schofield; R. E. Thomas; R. A. Barry; D. M. Castagnozzi; V. W. S. Chan; D. Marquis; S. A. Parikh; M. L. Stevens; E. A. Swanson; S. G. Finn; R. G. Gallager

1996-01-01

213

Antennas and propagation for body centric wireless communications  

Microsoft Academic Search

In this paper, on-body propagation modelling has been investigated applying various numerical computational techniques. Propagation measurements with body-worn antennas have been carried out at 2.4 GHz inside and outside an anechoic chamber respectively for narrowband communication channel characterisation. Both simulation and measurement results have been also obtained at the UWB (ultra wide-band) band.

Yang Hao; A. Alomainy; P. S. Hall; Y. I. Nechayev; C. G. Parini; C. C. Constantinou

2005-01-01

214

A 128-channel 6 mW wireless neural recording IC with spike feature extraction and UWB transmitter.  

PubMed

This paper reports a 128-channel neural recording integrated circuit (IC) with on-the-fly spike feature extraction and wireless telemetry. The chip consists of eight 16-channel front-end recording blocks, spike detection and feature extraction digital signal processor (DSP), ultra wideband (UWB) transmitter, and on-chip bias generators. Each recording channel has amplifiers with programmable gain and bandwidth to accommodate different types of biological signals. An analog-to-digital converter (ADC) shared by 16 amplifiers through time-multiplexing results in a balanced trade-off between the power consumption and chip area. A nonlinear energy operator (NEO) based spike detector is implemented for identifying spikes, which are further processed by a digital frequency-shaping filter. The computationally efficient spike detection and feature extraction algorithms attribute to an auspicious DSP implementation on-chip. UWB telemetry is designed to wirelessly transfer raw data from 128 recording channels at a data rate of 90 Mbit/s. The chip is realized in 0.35 mum complementary metal-oxide-semiconductor (CMOS) process with an area of 8.8 x 7.2 mm(2) and consumes 6 mW by employing a sequential turn-on architecture that selectively powers off idle analog circuit blocks. The chip has been tested for electrical specifications and verified in an ex vivo biological environment. PMID:19435684

Chae, Moo Sung; Yang, Zhi; Yuce, Mehmet R; Hoang, Linh; Liu, Wentai

2009-08-01

215

Wideband Love wave filters operating in GHz range on Cu-grating\\/rotated-YX-LiNbO3-substrate structure  

Microsoft Academic Search

The paper discusses the application of Love mode propagating on Cu-grating\\/rotated YX-LiNbO3-substrate structure to the development of ultra-wideband and low-loss RF SAW filters. Theoretical analysis suggests that high performance resonators with very small capacitance ratio may be realised using Cu gratings of the thickness of several percent of wavelength. It was also suggested that, in particular, on a 15°YX-LiNbO3-substrate structure,

Ken-ya Hashimoto; Hiroki Asano; Kenji Matsuda; Naofumi Yokoyama; Tatsuya Omori; Masatsune Yamaguchi

2004-01-01

216

Wideband Agile Digital Microwave Radiometer  

NASA Technical Reports Server (NTRS)

The objectives of this work were to take the initial steps needed to develop a field programmable gate array (FPGA)- based wideband digital radiometer backend (>500 MHz bandwidth) that will enable passive microwave observations with minimal performance degradation in a radiofrequency-interference (RFI)-rich environment. As manmade RF emissions increase over time and fill more of the microwave spectrum, microwave radiometer science applications will be increasingly impacted in a negative way, and the current generation of spaceborne microwave radiometers that use broadband analog back ends will become severely compromised or unusable over an increasing fraction of time on orbit. There is a need to develop a digital radiometer back end that, for each observation period, uses digital signal processing (DSP) algorithms to identify the maximum amount of RFI-free spectrum across the radiometer band to preserve bandwidth to minimize radiometer noise (which is inversely related to the bandwidth). Ultimately, the objective is to incorporate all processing necessary in the back end to take contaminated input spectra and produce a single output value free of manmade signals to minimize data rates for spaceborne radiometer missions. But, to meet these objectives, several intermediate processing algorithms had to be developed, and their performance characterized relative to typical brightness temperature accuracy re quirements for current and future microwave radiometer missions, including those for measuring salinity, soil moisture, and snow pack.

Gaier, Todd C.; Brown, Shannon T.; Ruf, Christopher; Gross, Steven

2012-01-01

217

Design of a miniature wideband radar experimental system  

Microsoft Academic Search

Wideband radars have been found more important both in civil and military applications. Micromation is one key technology for radars mounted at missiles, unmanned aerial vehicles (UAV), satellites, etc. The scheme of a miniature wideband radar experimental system is introduced in this paper, while the design and implementation of a wideband signal generator is analyzed in detail. The radar is

Zhang Xiao-wei; Li Ming; Zuo Lei

2011-01-01

218

Wireless Networks manuscript No. (will be inserted by the editor)  

E-print Network

- lenge. Wireless electromagnetic communication, by means of graphene-based nano-antennas, has been proposed to address this issue [7,18,34]. These tech- niques are expected to produce ultra-high freq

Politècnica de Catalunya, Universitat

219

Provision of IR-UWB wireless and baseband wired services over a WDM-PON.  

PubMed

A simple scheme to simultaneously generate an on-off keying or bi-phase modulation (BPM) impulse radio ultra wideband (IR-UWB) signal and a baseband wired signal in the optical domain using a dual-drive modulator is proposed and demonstrated. Although the two signals have spectral overlap in the optical spectrum, they are located at different frequency bands when converted to electrical signals at a photodetector (PD), which can be well separated by an electrical filter. An experiment is carried out. Eye diagrams, electrical spectra and BER measurements show that the co-channel interference between the UWB and the wired signals is small for a single-channel 36-km fiber link to provide 1.25-Gb/s UWB wireless and 1.25-Gb/s baseband wired services. The inter-channel interference is also small and negligible when the link is operated together with two other 1.25 Gb/s baseband wired links, which demonstrates that a conventional WDM-PON can be upgraded to provide additional UWB services without affecting the existing services by modifying the modulators in the center office and inserting UWB antennas in the optical network units. PMID:22274021

Pan, Shilong; Yao, Jianping

2011-12-12

220

Optical wideband high-voltage measurement system  

Microsoft Academic Search

A wideband fiber-optic system for the measurement of ac high voltages is presented. The system is based on a capacitively coupled Pockels cell which works as a passive voltage sensor. The lower frequency limit is a few Hz and the upper is 150–230 MHz depending on the application. Other system characteristics are excellent electrical noise suppression, large voltage range, high

H. M. Hertz; P. Thomsen

1987-01-01

221

Wide-band characterization of current probes  

Microsoft Academic Search

The use of current probes for the injection of wide-band disturbance in electromagnetic compatibility applications requires their accurate characterization up to few gigahertz. While the representation of the current probe with a simple transformer is acceptable at low frequencies, the spectral content of fast signals requires models which are accurate even at gigahertz frequencies. This can be accomplished directly by

Graziano Cerri; Roberto De Leo; Valter Mariani Primiani; Stefano Pennesi; Paola Russo

2003-01-01

222

Wideband Planar Log-Periodic Antenna  

Microsoft Academic Search

A compact planar wideband microstrip antenna is introduced. The antenna is a log-periodic antenna with 7 dipole elements. The antenna is designed to function in the frequency range of 500 to 700 MHz. It has a dimension of 268 mm by 145 mm by 3 mm. The matching is better than -10 dB in the working bandwidth. The proposed antenna

M. M. Tajdini; M. Shahabadi

2007-01-01

223

A novel wideband 140 GHz gyrotron amplifier  

E-print Network

The theory, design and experimental results of a wideband 140 GHz, 1 kW pulsed gyro-traveling wave amplifier are presented. The gyro- TWA operates in the HE(0,6) mode of a novel cylindrical confocal waveguide using a ...

Joye, Colin D., 1980-

2008-01-01

224

Technology advances in wideband packet switching  

Microsoft Academic Search

The authors examine some recent technology advances in the evolution of wideband packet technology (WPT). These advances include contention resolution in WPT switch fabrics, GaAs implementation of WPT switch fabric, and packet processing in trunk interfaces. It is concluded that WPT architectures are ideally suited for aggressive incorporation in advanced VLSI technology particularly for the implementation of the core of

A. K. Vaidya; M. A. Pashan

1988-01-01

225

Wideband Circularly Polarized Vertical Patch Antenna  

Microsoft Academic Search

A compact circularly polarized (CP) vertical patch antenna is presented that employs a microstrip to slot-line transition for a wideband operation. The antenna is composed of two vertical patches, which are shaped as helix to obtain a broadband CP performance. The loop structure and the vertical overlap configuration lead to significant size reduction as much as 48% when compared to

Ze-Hai Wu; Edward Kai-Ning Yung

2008-01-01

226

Wideband thin resistive metamaterial radar absorbing screen  

Microsoft Academic Search

It has been demonstrated that two layer metamaterial Hilbert curve array constructed from low conductivity material can act as a thin wideband radar absorbing screen. The advantage of using Hilbert curve over traditional circuit analogue radar absorbing screen is the smaller unit cell size, resulting in reduced coupling to higher order Floquent modes and reduced diffraction effects, which in turn

A. Noor; Zhirun Hu; H. H. Ouslimani; A. Priou

2009-01-01

227

Design of a wideband radar absorbing structure  

Microsoft Academic Search

In this paper, a thin planar electromagnetic absorber consisting of two lossy Frequency Selective Surface (FSS) layers is introduced. The layers are separated by foam material and they are backed by the ground plane. Square rings and crossed dipoles are used in the design of these lossy layers. A wideband absorption characteristic is achieved for zero degrees of incidence angle

Egemen Yildirim; Ozlem Aydin Civi

2011-01-01

228

Wideband Spectrum Sensing in Cognitive Radio Networks  

Microsoft Academic Search

Spectrum sensing is an essential enabling function- ality for cognitive radio networks to detect spectrum holes and opportunistically use the under-utilized frequency bands without causing harmful interference to legacy networks. This paper introduces a novel wideband spectrum sensing technique, called multiband joint detection, which jointly detects the signal energy levels over multiple frequency bands rather than consider one band at

Zhi Quan; Shuguang Cui; Ali H. Sayed; H. Vincent Poor

2008-01-01

229

Wireless field bus communication with software defined IR-UWB in a manufacturing environment  

Microsoft Academic Search

This paper elaborates a concept for a wireless field bus communication with software defined ultra wide band with impulse radio modulation (IR-UWB) in manufacturing environments. A wireless field bus offers an important improvement to the smart factory due to increasing requirements for connectivity, adaptability and flexibility. Former analysis showed the benefit of using UWB technology for the wireless field bus

T. Alpert; F. Lang; M. Gro?zing; M. Berroth

2010-01-01

230

An Accelerator-Based Wireless Sensor Network Processor in 130nm CMOS  

E-print Network

An Accelerator-Based Wireless Sensor Network Processor in 130nm CMOS Mark Hempstead ARM Ltd-1-60558-626-7/09/10 ...$10.00. Keywords Wireless Sensor Networks, Ultra-Low Power, Accelerator-based 1. INTRODUCTION Networks of wireless sensor networks (WSNs) have uti- lized nodes based on off-the-shelf general purpose

Hempstead, Mark

231

Wideband aperture array using RF channelizers and massively parallel digital 2D IIR filterbank  

NASA Astrophysics Data System (ADS)

Wideband receive-mode beamforming applications in wireless location, electronically-scanned antennas for radar, RF sensing, microwave imaging and wireless communications require digital aperture arrays that offer a relatively constant far-field beam over several octaves of bandwidth. Several beamforming schemes including the well-known true time-delay and the phased array beamformers have been realized using either finite impulse response (FIR) or fast Fourier transform (FFT) digital filter-sum based techniques. These beamforming algorithms offer the desired selectivity at the cost of a high computational complexity and frequency-dependant far-field array patterns. A novel approach to receiver beamforming is the use of massively parallel 2-D infinite impulse response (IIR) fan filterbanks for the synthesis of relatively frequency independent RF beams at an order of magnitude lower multiplier complexity compared to FFT or FIR filter based conventional algorithms. The 2-D IIR filterbanks demand fast digital processing that can support several octaves of RF bandwidth, fast analog-to-digital converters (ADCs) for RF-to-bits type direct conversion of wideband antenna element signals. Fast digital implementation platforms that can realize high-precision recursive filter structures necessary for real-time beamforming, at RF radio bandwidths, are also desired. We propose a novel technique that combines a passive RF channelizer, multichannel ADC technology, and single-phase massively parallel 2-D IIR digital fan filterbanks, realized at low complexity using FPGA and/or ASIC technology. There exists native support for a larger bandwidth than the maximum clock frequency of the digital implementation technology. We also strive to achieve More-than-Moore throughput by processing a wideband RF signal having content with N-fold (B = N Fclk/2) bandwidth compared to the maximum clock frequency Fclk Hz of the digital VLSI platform under consideration. Such increase in bandwidth is achieved without use of polyphase signal processing or time-interleaved ADC methods. That is, all digital processors operate at the same Fclk clock frequency without phasing, while wideband operation is achieved by sub-sampling of narrower sub-bands at the the RF channelizer outputs.

Sengupta, Arindam; Madanayake, Arjuna; Gómez-García, Roberto; Engeberg, Erik D.

2014-05-01

232

Electromagnetic Field Measurement in Presence of Radiofrequency Wideband Digital Signals  

Microsoft Academic Search

This paper describes an experimental research carried out to evaluate the efficiency of traditional exposure assessment procedures when applied to the measurement of radiofrequency electromagnetic field radiated by digital wideband signal transmitters (802.11x, 802.16x, DVB-x). For this purpose, it was analysed both the performance of wideband measuring procedures based on the use of wideband field probes and the behaviour of

Daniele Trinchero; Benedetta Fiorelli; Riccardo Stefanelli; Laura Anglesio; Alberto Benedetto; Stefano Trinchero; Giovanni d'Amore; Michele Borsero; Giuseppe Vizio

233

Towards a Smart Wireless Integrated Module (SWIM) on Flexible Organic Substrates Using Inkjet Printing Technology for Wireless Sensor Networks  

E-print Network

quantities of sensor nodes [1][2]. These challenges emphasize the need for low-cost and eco-friendly solutions to realize ultra-low cost and eco-friendly sensor networks [3]. This paper presents the first IEEE in the large scale manufacturing of ultra-low-cost eco-friendly "green" wireless sensor networks. INTRODUCTION

Tentzeris, Manos

234

UWB wireless interconnect scheme for communicating devices within small conducting enclosure  

Microsoft Academic Search

This paper presents a novel concept which proposes the use of an ultra-wide bandwidth (UWB) ultra small scale wireless interconnect scheme for use within a electrically small enclosure. Such ultra small environments (size ? 10 wavelengths) are topologically much more complex, being more cluttered, than typical indoor environments (size ? 10 wavelengths). The concept is presented using an aluminium tower

Javier Gelabert; David Edwards; Christopher J. Stevens

2011-01-01

235

Wireless Technician  

ERIC Educational Resources Information Center

One of the hottest areas in technology is invisible. Wireless communications allow people to transmit voice messages, data, and other signals through the air without physically connecting senders to receivers with cables or wires. And the technology is spreading at lightning speed. Cellular phones, personal digital assistants, and wireless

Tech Directions, 2011

2011-01-01

236

Wideband Circularly-Polarized Patch Antenna  

Microsoft Academic Search

A novel wideband circularly-polarized patch antenna is presented. First, a new broadband 90deg hybrid feed network is proposed to have a bandwidth of 75% for the 10-dB return loss, good two output ports amplitude balance and a consistent 90deg (plusmn3deg) phase difference between two output ports. Then, a circular patch antenna fed by four sequential-rotation proximity-coupled L-probes orientated to have

Lei Bian; Yong-Xin Guo; L. C. Ong; Xiang-Quan Shi

2006-01-01

237

Fast wideband search for spurious responses  

NASA Astrophysics Data System (ADS)

A technique for quickly searching frequencies in a signal path to find and measure low-level spurs is described. It couples a wideband tuned receiver with a tuned digital, parallel filter bank analyzer to greatly reduce spur testing times. The receiver is step-tuned across the region of frequencies to be searched, and at each step the filter bank is step-tuned across the IF output. An example system is described, and search time and sensitivity are discussed.

Cassidy, Kevin; Snell, Jay

1992-02-01

238

Wideband quasi-log-periodic microstrip antenna  

Microsoft Academic Search

The paper describes a new design method for a wideband array of log-periodically sealed microstrip resonator antennas. The radiating elements are series-fed by a simple coplanar microstrip network. This network consists of an open-circuited feed line with a branch line connected to each radiating element. Both a network and a radiating model for the complete structure are explained. These models

H. Pues; J. Bogaers; R. Pieck; A. van de Capelle

1981-01-01

239

Wideband channel model for aeronautical telemetry  

Microsoft Academic Search

A multipath channel model for wideband aeronautical telemetry links is presented. Channel sounding data were collected at Edwards AFB, CA, at both L-band and lower S-band. Frequency domain analysis techniques were used to evaluate candidate channel models. The channel model is composed of three propagation paths: a line-of-sight direct path and two specular reflections. The first specular reflection is characterized

MICHAEL RICE; A. Davis; CHRISTIAN BETTWEISER

2004-01-01

240

AMiBA WIDEBAND ANALOG CORRELATOR  

SciTech Connect

A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband intermediate frequency distribution, back-end signal processing, and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.

Li, Chao-Te; Kubo, Derek Y.; Lin, Kai-Yang; Chen, Ming-Tang; Ho, P. T. P.; Chen, Chung-Cheng; Han, Chih-Chiang; Oshiro, Peter; Martin-Cocher, Pierre; Chang, Chia-Hao; Chang, Shu-Hao; Altamirano, Pablo; Jiang, Homin [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Wilson, Warwick [Australia Telescope National Facility, Epping, NSW 1710 (Australia); Chiueh, Tzi-Dar; Lien, Chun-Hsien; Wang, Huei; Wei, Ray-Ming; Yang, Chia-Hsiang [National Taiwan University, Taipei 106, Taiwan (China); Peterson, Jeffrey B., E-mail: ctli@asiaa.sinica.edu.t [Carnegie-Mellon University, Pittsburgh, PA 15213 (United States)

2010-06-10

241

WiMedia Ultra-Wide Band Transmission in Radio over Fiber using Multimode Fiber  

Microsoft Academic Search

WiMedia compliant Ultra-Wideband signals are transmitted in a low cost Radio over Fiber system over extended distances to 900 m. Measured packet error rate shows the merit of UWB transmission and extension in the ROF medium. Significant range extension has been demonstrated using ROF.

Ming-Li Yee; Yong-Xin Guo; Viet Hung Pham; Ling Chuen Ong

2007-01-01

242

Wireless Technology  

NSDL National Science Digital Library

Wireless is just another name for radio. And of course, wireless is certainly not new. It was discovered in the late 1800s and quickly developed in the early 1900s by Marconi and others. Radio has many uses which include radio broadcasting (AM, FM, digital and satellite), 2-way radio (public service, aircraft, marine, etc.), personal and hobby (CB, FRS, ham radio, RC, etc.), and telemetry. Cell phones are two way radios as are wireless local area networks. TV, radar, satellites, and navigation systems like GPS are radio. Today radio is mostly taken for granted. However over the past decades, radio has changed our lives. The developments with the greatest impact are cell phones, wireless local area networks (WLANs) for computers, and short range radios for a variety of applications. These applications are today referred to as wireless. This module introduces you to basic radio concepts.

2011-01-03

243

456 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 7, 2008 A Printed Log-Periodic Koch-Dipole Array (LPKDA)  

E-print Network

]­[5] are introduced as the basic structural elements of a wideband log-periodic Koch-dipole array (LPKDA.1109/LAWP.2008.2001765 TABLE I SINGLE ELEMENT MINIATURIZATION (EUCLIDEAN VERSUS KOCH) need to be based456 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 7, 2008 A Printed Log-Periodic Koch

Tentzeris, Manos

244

Design of wideband circularly polarized aperture-coupled microstrip antennas  

Microsoft Academic Search

Two variations of a novel feeding technique for a wideband circularly polarized aperture-coupled microstrip antenna are described. Prototype designs for wideband linearly polarized elements are first presented, and then used for circularly polarized designs. Techniques used for design of the feed network are detailed, for both series feed and parallel feed versions. Experimental results are shown for each antenna, and

Stephen D. Targonski; David M. Pozar

1993-01-01

245

Simulated Wideband Oxygen Sensor Using the Arduino Board.  

E-print Network

Simulated Wideband Oxygen Sensor Using the Arduino Board. Dr. Pushkin EE290 Timothy Pratt 28 � April - 09 #12;Simulated Wideband Oxygen Sensor A typical narrow band oxygen sensor is only good short range. And that depends of temperature of the exhaust gas even with a heated oxygen sensor

Kachroo, Pushkin

246

BANDPASS / WIDEBAND ADC ARCHITECTURE USING PARALLEL DELTA SIGMA MODULATORS  

E-print Network

wideband signals. It is based on the use of parallel analog delta sigma modulators, where each modulatorBANDPASS / WIDEBAND ADC ARCHITECTURE USING PARALLEL DELTA SIGMA MODULATORS Ali Beydoun and Philippe must be handled such as: enlarging the frequency bandwidth of the analog to digital converter

Boyer, Edmond

247

Wideband Waveform Optimization with Energy Detector Receiver in Cognitive Radio  

E-print Network

Wideband Waveform Optimization with Energy Detector Receiver in Cognitive Radio Zhen Hu Department investigates the transmitted waveform optimization issues for wideband cognitive radio with energy detector receiver. The motivation is to provide a cheap cognitive radio network with simple and cheap cognitive

Qiu, Robert Caiming

248

Compact wideband antenna above a wideband non-uniform artificial magnetic conductor  

NASA Astrophysics Data System (ADS)

A compact wideband antenna place above a non-uniform artificial magnetic conductor (AMC) is presented. The antenna is composed of a wideband coplanar waveguide fed antenna, with wideband harmonic suppression characteristic using non-uniform defected ground structure. Besides, a non-uniform wideband AMC is designed. The AMC unit cell is composed of a square patch into which a four arms spiral shape is etched. It exhibits a wider ±90° bandwidth than the spiral unit cell and a smaller size than the square patch unit cell. The antenna is placed above the proposed AMC structure formed by 6 × 5 unit cells. The overall dimensions of the complete structure are 0.7 × 0.6 ? {0/2}, where ? 0 is the free-space wavelength at the lowest frequency. It offers a low-profile configuration with a total thickness of ? 0/14.3, and it is matched between 2.5 and 5.4 GHz (73.5 %). Furthermore, it has a stable main lobe radiation pattern in the E- and H-planes within the operating frequency band. Moreover, compared with the antenna without AMC, the broadside realized gain is significantly increased. A prototype has been realized, and there is a good agreement between simulated and measured results. Furthermore, the proposed structure presents a size reduction of about 34 %, and better radiation characteristics in comparison with the conventional square AMC.

Damaj, Lana; Lepage, Anne-Claire; Begaud, Xavier

2014-08-01

249

RF Design of a Wideband CMOS Integrated Receiver for Phased Array Applications  

NASA Astrophysics Data System (ADS)

New silicon CMOS processes developed primarily for the burgeoning wireless networking market offer significant promise as a vehicle for the implementation of highly integrated receivers, especially at the lower end of the frequency range proposed for the Square Kilometre Array (SKA). An RF-CMOS ‘Receiver-on-a-Chip’ is being developed as part of an Australia Telescope program looking at technologies associated with the SKA. The receiver covers the frequency range 500 1700 MHz, with instantaneous IF bandwidth of 500 MHz and, on simulation, yields an input noise temperature of < 50 K at mid-band. The receiver will contain all active circuitry (LNA, bandpass filter, quadrature mixer, anti-aliasing filter, digitiser and serialiser) on one 0.18 ?m RF-CMOS integrated circuit. This paper outlines receiver front-end development work undertaken to date, including design and simulation of an LNA using noise cancelling techniques to achieve a wideband input-power-match with little noise penalty.

Jackson, Suzy A.

2004-06-01

250

Wireless Communication  

NSDL National Science Digital Library

This quicktime animation examines the basics in wireless communication. Wireless communication has become pervasive in everyday life, providing convenience, piece of mind as well as emergency preparedness for its users through instant accessibility. The cell phone antenna is the link to the outside world. Designed to transmit as well as receive the RF signals, it efficiently couples the electromagnetic waves to the transmitter and receiver.

Van Zeghbroeck, Bart J.

2012-08-08

251

Space-Time Bayesian Compressed Spectrum Sensing for Wideband Cognitive Radio Networks  

Microsoft Academic Search

Wideband spectrum sensing in cognitive radio networks remains an open challenge due to wideband spectrum acquisition implementation. Compressed spectrum sensing provides a powerful approach to acquire wideband signals. We purpose a probabilistic Space-time Bayesian Compressed Spectrum Sensing (ST-BCSS) to combat the noise in wideband compressed spectrum sensing. We present an informative hierarchical prior probabilistic model to recover the compressed spectrum

Zhenghao Zhang; Husheng Li; Depeng Yang; Changxing Pei

2010-01-01

252

Wideband versatile radio-frequency spectrum analyzer.  

PubMed

Operation of a wideband, versatile optical spectrum analyzer for radio-frequency (RF) signals is demonstrated. The device is based on spectral hole burning (SHB). The demonstration features 2.3-GHz instantaneous bandwidth, 500-kHz resolution, and a 32-dB dynamic range. A true RF signal, transferred to the optical carrier with the help of a Mach-Zehnder modulator, is analyzed with optical carrier suppression and zooming capabilities. This is to the authors' knowledge the largest instantaneous bandwidth ever demonstrated for a SHB-based processor in rare-earth-doped crystals. PMID:12659254

Lavielle, V; Lorgeré, I; Le Gouët, J L; Tonda, S; Dolfi, D

2003-03-15

253

Wideband heterodyne receiver for laser communication system  

NASA Technical Reports Server (NTRS)

A heterodyne receiver for laser communication is described which includes a front end having a cooled photomixer contained in a hermetically sealed spaced quality housing designed for wide bandwidth transmission. The photomixer is coupled through a wideband preamplifier to the receiver back end which includes a frequency tracking network and demodulating equipment. The receiver is capable of tracking a Doppler frequency shift of 750 MHz, positive or negative, and has an instantaneous intermediate frequency information bandwidth of 400 MHz. The receiver system is also capable of operating over a wide temperature range and is designed to be suitable for use in outer space communication.

Flattau, T.; Lange, R. A.; Mellars, B.; Peyton, J.; Wolczok, J. M. (inventors)

1977-01-01

254

Miniature biotelemeter gives multichannel wideband biomedical data  

NASA Technical Reports Server (NTRS)

A miniature biotelemeter was developed for sensing and transmitting multiple channels of biomedical data over a radio link. The design of this miniature, 10-channel, wideband (5 kHz/channel), pulse amplitude modulation/ frequency modulation biotelemeter takes advantage of modern device technology (e.g., integrated circuit operational amplifiers, complementary symmetry/metal oxide semiconductor logic, and solid state switches) and hybrid packaging techniques. The telemeter is being used to monitor 10 channels of neuron firings from specific regions of the brain in rats implanted with chronic electrodes. Design, fabrication, and testing of an engineering model biotelemeter are described.

Carraway, J. B.

1972-01-01

255

Real-time wideband holographic surveillance system  

DOEpatents

A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.

Sheen, David M. (1917 Hood, Richland, WA 99352); Collins, H. Dale (1751 Duluth, Richland, WA 99352); Hall, Thomas E. (8301 W. Entiat Pl., Kennewick, WA 99336); McMakin, Douglas L. (2173 Shasta Ave., Richland, WA 99352); Gribble, R. Parks (1215 Cottonwood Dr., Richland, WA 99352); Severtsen, Ronald H. (1803 Birch Ave., Richland, WA 99352); Prince, James M. (3029 W. 2nd Ave., Apt. F95, Kennewick, WA 99336); Reid, Larry D. (Rt. 1, Box 1291B, Benton City, WA 99320)

1996-01-01

256

Wireless Communications  

NSDL National Science Digital Library

Wireless communications is an industry that is growing at an incredible rate. Cellular phones are the most obvious example of this trend; it is hard to go anywhere without seeing someone using one. Rapidly advancing technologies and lower prices are making this all possible. At the current pace, there seems to be no limit to what is possible in the wireless industry.To learn about the events that led up to present day wireless communications, this site offers a very informative history of telecommunications (1) that goes all the way back to the time of carrier pigeons. A good introduction to wireless networking can be found in this mini-tutorial (2). The best parts of this tutorial are the discussions of many recent wireless developments and technologies. There are a few interactive games and activities that are supposed to be instructive and entertaining, but some of them can be annoying. For the more technically savvy user, the third site (3) starts by describing many of the principles that drive current wireless systems. The second part examines the technologies that will be used in future generations of services. To build on this material, the third generation mobile communications systems (3G) is the central topic at 3G Newsroom (4), providing breaking news about the development of 3G technology. Additionally, the site has an excellent introduction to 3G, including its applications and specifications. One of the advancements that is paving the way toward 3G is Bluetooth, which is explained in great detail here (5). This technology is capable of very high data transfer rates, but there are some limitations, which are all discussed in the articles on the site. Although Bluetooth is raising plenty of interest, this recent news story (6) is creating more than its share of debate. It outlines a very controversial move by the FCC to allow the use of ultrawideband technology in commercial wireless applications. The author explains in simple terms why there are so many concerns about something that could revolutionize wireless systems. The evolution of the global system for mobile communications (GSM) is traced at GSM World (7). Here users can learn about the roots of the wireless industry as well as what is in store for the future. A special section addresses health concerns associated with mobile phone use. Radio was one of the earliest form of wireless communication, and the Invention of Radio (8) documents the people and events that made it what it is today. The stories of such famous scientists and inventors as Marconi, DeForest, and Armstrong are told in brief accounts, and there is even a link to the well known War of the Worlds radio broadcast.

Leske, Cavin.

2002-01-01

257

A 255 MHz Programmable Gain Amplifier and Low-Pass Filter for Ultra Low Power Impulse-Radio UWB Receivers  

Microsoft Academic Search

A 90 nm-CMOS power-optimized analog baseband chain for ultra-low-power impulse-radio ultra-wideband (IR-UWB) receivers is presented. The proposed device merges the functions of a programmable gain amplifier (PGA) and a low-pass filter (LPF). It consists of the cascade of three biquadratic cells made up by opamps in a series-shunt configuration, which features high input impedance, low load effects in the cascade

Stefano D'Amico; Marco De Blasi; Marcello De Matteis; Andrea Baschirotto

2012-01-01

258

Highly Stable Wideband Microwave Extraction by Synchronizing Widely Tunable Optoelectronic Oscillator with Optical Frequency Comb  

NASA Astrophysics Data System (ADS)

Optical frequency combs (OFCs), based on mode-locked lasers (MLLs), have attracted considerable attention in many fields over recent years. Among the applications of OFCs, one of the most challenging works is the extraction of a highly stable microwave with low phase noise. Many synchronisation schemes have been exploited to synchronise an electronic oscillator with the pulse train from a MLL, helping to extract an ultra-stable microwave. Here, we demonstrate novel wideband microwave extraction from a stable OFC by synchronising a single widely tunable optoelectronic oscillator (OEO) with an OFC at different harmonic frequencies, using an optical phase detection technique. The tunable range of the proposed microwave extraction extends from 2 GHz to 4 GHz, and in a long-term synchronisation experiment over 12 hours, the proposed synchronisation scheme provided a rms timing drift of 18 fs and frequency instabilities at 1.2 × 10-15/1 s and 2.2 × 10-18/10000 s.

Hou, D.; Xie, X. P.; Zhang, Y. L.; Wu, J. T.; Chen, Z. Y.; Zhao, J. Y.

2013-12-01

259

A smart wireless integrated module (SWIM) on organic substrates using inkjet printing technology.  

E-print Network

??This thesis investigates inkjet printing of fully-integrated modules fabricated on organic substrates as a system-level solution for ultra-low-cost and eco-friendly mass production of wireless sensor… (more)

Palacios, Sebastian R.

2014-01-01

260

Wireless Communications  

NASA Technical Reports Server (NTRS)

A technology utilization project led to the commercial adaptation of a Space Shuttle Orbiter wireless infrared voice communications system. The technology was adapted to a LAN system by Wilton Industries, one of the participants. Because the system is cable-free, installation charges are saved, and it can be used where cable is impractical. Resultant products include the IRplex 6000. Transceivers can be located anywhere and can include mobile receivers. The system provides wireless LAN coverage up to 44,000 square feet. applications include stock exchange communications, trade shows, emergency communications, etc.

1991-01-01

261

Energy Savings by Wideband Temperature Control in Telephone Offices  

E-print Network

-effective measure for reducing such energy use has been Wideband Temperature Control which provides no heating, cooling or fan operation between 65 F and 80 F, except for special equipment or ventilation requirements. Building energy load and use programs...

Lingousky, J. E.; McKay, J. R.

1983-01-01

262

Wafer Probe Station, Low Noise Amplifiers, and Wideband Feed Developments  

E-print Network

-ridge flared horn wideband feeds #12;Wafer Fabrication of LNA's and Other Radiometer Components 20-Sep-2011. · Station can handle a 100mm diameter wafer with several thousand MMIC's · Motor-driven precision wafer

Weinreb, Sander

263

Wireless Tots  

ERIC Educational Resources Information Center

The first wireless technology program for preschoolers was implemented in January at the Primrose School at Bentwater in Atlanta, Georgia, a new corporate school operated by Primrose School Franchising Co. The new school serves as a testing and training facility for groundbreaking educational approaches, including emerging innovations in…

Scott, Lee-Allison

2003-01-01

264

Wireless endoscopy  

Microsoft Academic Search

Background: Miniaturization of electronic components may allow the construction of new types of endoscopes that no longer require external wires, cables, or optical fibers. Our aim was to assess the feasibility of wireless endoscopy and to construct experimental prototypes using miniature charge-coupled device cameras, light sources, microwave transmitters, and batteries. Methods: Feasibility, dimensions of miniature components, and power requirements were

Feng Gong; Paul Swain; Timothy Mills

2000-01-01

265

Elementary Wideband Timing of Radio Pulsars  

NASA Astrophysics Data System (ADS)

We present an algorithm for the simultaneous measurement of a pulse time-of-arrival (TOA) and dispersion measure (DM) from folded wideband pulsar data. We extend the prescription from Taylor's 1992 work to accommodate a general two-dimensional template "portrait," the alignment of which can be used to measure a pulse phase and DM. We show that there is a dedispersion reference frequency that removes the covariance between these two quantities and note that the recovered pulse profile scaling amplitudes can provide useful information. We experiment with pulse modeling by using a Gaussian-component scheme that allows for independent component evolution with frequency, a "fiducial component," and the inclusion of scattering. We showcase the algorithm using our publicly available code on three years of wideband data from the bright millisecond pulsar J1824-2452A (M28A) from the Green Bank Telescope, and a suite of Monte Carlo analyses validates the algorithm. By using a simple model portrait of M28A, we obtain DM trends comparable to those measured by more standard methods, with improved TOA and DM precisions by factors of a few. Measurements from our algorithm will yield precisions at least as good as those from traditional techniques, but is prone to fewer systematic effects and is without ad hoc parameters. A broad application of this new method for dispersion measure tracking with modern large-bandwidth observing systems should improve the timing residuals for pulsar timing array experiments, such as the North American Nanohertz Observatory for Gravitational Waves.

Pennucci, Timothy T.; Demorest, Paul B.; Ransom, Scott M.

2014-08-01

266

Wideband, planar, log-periodic balun  

Microsoft Academic Search

This paper presents the design and performance characteristics of a new planar balun structure. The design is based on the log-periodic antenna theory. The design guidelines, as well as simulated and measured results are presented. It is shown that the new balun has greater than one octave bandwidth. The log-periodic balun will find applications in wireless communication circuits such as

Mahmoud Basraoui; S. N. Prasad

1998-01-01

267

Collaborative wideband sensing for cognitive radios  

Microsoft Academic Search

Cognitive radio (CR) has recently emerged as a promising technology to revolutionize spectrum utilization in wireless communications. In a CR network, secondary users continuously sense the spectral environment and adapt transmission parameters to opportunistically use the available spectrum. A fundamental problem for CRs is spectrum sensing; secondary users need to reliably detect weak primary signals of possibly different types over

Zhi Quan; Shuguang Cui; H. Poor; Ali H. Sayed

2008-01-01

268

Using Hierarchical Data Mining to Characterize Performance of Wireless System Configurations  

Microsoft Academic Search

This paper presents a statistical framework for assessing wireless systems performance using hierarchical data mining techniques. We consider WCDMA (wideband code division multiple access) systems with two-branch STTD (space time transmit diversity) and 1\\/2 rate convolutional coding (forward error correction codes). Monte Carlo simulation estimates the bit error probability (BEP) of the system across a wide range of signal-to-noise ratios

Alex Verstak; Naren Ramakrishnan; Kyung Kyoon Bae; William H. Tranter; Layne T. Watson; Jian He; Clifford A. Shaffer; Theodore S. Rappaport

2002-01-01

269

Low-power radio frequency circuit architectures for portable wireless communications  

Microsoft Academic Search

Ultra-low-power implementations of radio-frequency integrated circuits are benefiting from rapid improvements in integrated circuit technology, circuit architecture techniques and wireless system innovations. Some of the key technological developments driving this field are discussed, in addition to new approaches for the realization of next generation wireless circuits and systems that dissipate very little dc power

Lawrence E. Larson

1998-01-01

270

Digital Wireless Communication  

E-print Network

Digital Wireless Communication: Physical Layer Exploitation Wireless Networking and Communications Signals and Systems Digital Signal Processing Analog Communication Digital Communication Intro to Wireless;Why at the Graduate Level? It involves many different areas of expertise Digital communication

Heath Jr., - Robert W.

271

Wireless services business plan  

E-print Network

The primary goals of this thesis were to analyze the market for wireless applications/services and create a business plan for a viable wireless application. There has been tremendous hype relating to wireless data services ...

Koh, Bong (Bong Dug)

2005-01-01

272

Performance evaluation of an ultra-low power receiver for body area networks (BAN)  

Microsoft Academic Search

The main bottleneck to achieve energy autonomy in body area networks (BAN) is the design of an ultra low power yet reliable wireless system. In this paper, we first demonstrate the feasibility of an ultra low power receiver by presenting our implemented receiver chip that could operate on a total power of 479.5 uW, which is more than one order

Li Huang; Pieter Harpe; Cui Zhou; Simonetta Rampu; Maja Vidojkovic; Guido Dolmans; Harmke de Groot; Koji Imamura

2010-01-01

273

Wideband phased array antennas and compact, harmonic-suppressed microstrip filters  

E-print Network

wideband phased array antennas, one produces linear polarization and one produces circular polarization. The main difference between these two phased array antennas is the antenna array. For the linearly polarized array, a wideband microstrip line...

Tu, Wen-Hua

2009-05-15

274

Wireless Sensing and Control  

Microsoft Academic Search

Wireless technologies can play a significant role in the monitoring and control of civil structures. Structural sensing and control technologies can benefit in terms of installation cost and time from wireless communication and embedded computing. This paper discusses the development of a low-cost wireless sensing system judiciously designed for civil structures. By incorporating an actuation signal generation interface, the wireless

Yang Wang; Kenneth J. Loh; Jerome P. Lynch; Kincho H. Law

275

Transform-based wideband array processing  

NASA Astrophysics Data System (ADS)

This contract has funded two projects in full and one project in part. The two fully funded projects focus on the application of random coefficient models to wideband high-resolution direction finding and transient signal detection and estimation. The partially funded project involves the analysis of nonlinear, possibly chaotic, dynamical systems. It has been shown that the random coefficient model is much better suited to modeling sensor array data than the autoregressive model is. Application of the wavelet transform to the detection of transient signals with an array of sensors is being examined. This approach has led to a directional multirate filter bank structure that decomposes the incoming signal into decaying exponentials. System identification algorithms that depend on gradient descent methods have been found to degrade significantly if the time-series or, equivalently, the system that produced the time-series is chaotic. A careful analysis of these degradations has led to algorithms which are much less sensitive to the potentially chaotic nature of these nonlinear systems.

Williams, Douglas B.; Madan, Rabinder N.

1992-01-01

276

A Resistive Wideband Space Beam Splitter  

E-print Network

We present the design, construction and measurements of the electromagnetic performance of a wideband space beam splitter. The beam splitter is designed to power divide the incident radiation into reflected and transmitted components for interferometer measurement of spectral features in the mean cosmic radio background. Analysis of a 2-element interferometer configuration with a vertical beam splitter between a pair of antennas leads to the requirement that the beam splitter be a resistive sheet with sheet resistance {\\eta}o /2, where {\\eta}o is the impedance of free space. The transmission and reflection properties of such a sheet is computed for normal and oblique incidences and for orthogonal polarizations of the incident electric field. We have constructed such an electromagnetic beam splitter as a square soldered grid of resistors of value 180 Ohms (approximately {\\eta}o /2) and a grid size of 0.1 m, and present measurements of the reflection and transmission coefficients over a wide frequency range bet...

Mahesh, Nivedita; Shankar, N Udaya; Raghunathan, Agaram

2014-01-01

277

An earth-isolated optically coupled wideband high voltage probe powered by ambient light  

E-print Network

An earth-isolated optically coupled wideband high voltage probe powered by ambient light Xiang Zhai) An earth-isolated optically coupled wideband high voltage probe powered by ambient light Xiang Zhaia online 9 October 2012) An earth-isolated optically-coupled wideband high voltage probe has been developed

Bellan, Paul M.

278

Wide band cryogenic ultra-high vacuum microwave absorber  

DOEpatents

An absorber wave guide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the wave guide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the wave guide.

Campisi, Isidoro E. (Newport News, VA)

1992-01-01

279

The effects of antenna directivity on path loss and multipath propagation in UWB indoor wireless channels  

Microsoft Academic Search

The effects of antenna directivity on path loss and multipath propagation in the ultra-wideband (UWB) indoor channel are analyzed for different transmitter\\/receiver (Tx\\/Rx) antenna combinations in the 2 GHz to 6 GHz frequency band. A statistical model of the path loss in the channel is presented, where the parameters in the model (i.e., path loss exponent and shadow fading statistics)

Jason A. Dabin; Nan Ni; Alexander M. Haimovich; Edip Niver; Haim Grebel

2003-01-01

280

An inductorless CMOS programmable-gain amplifier with a > 3 GHz bandwidth for 60 GHz wireless transceivers  

NASA Astrophysics Data System (ADS)

An inductorless wideband programmable-gain amplifier (PGA) for 60 GHz wireless transceivers is presented. To attain wideband characteristics, a modified Cherry—Hooper amplifier with a negative capacitive neutralization technique is employed as the gain cell while a novel circuit technique for gain adjustment is adopted; this technique can be universally applicable in wideband PGA design and greatly simplifying the design of wideband PGA. By cascading two gain cells and an output buffer stage, the PGA achieves the highest gain of 30 dB with the bandwidth much wider than 3 GHz. The PGA has been integrated into one whole 60 GHz wireless transceiver and implemented in the TSMC 65 nm CMOS process. The measurements on the receiver front-end show that the receiver front-end achieves an 18 dB variable gain range with a > 3 GHz bandwidth, which proves the proposed PGA achieves an 18 dB variable gain range with a bandwidth much wider than 3 GHz. The PGA consumes 10.7 mW of power from a 1.2-V supply voltage with a core area of only 0.025 mm2.

Wei, Zhu; Baoyong, Chi; Lixue, Kuang; Wen, Jia; Zhihua, Wang

2014-10-01

281

Ultra-broadband terahertz metamaterial absorber  

NASA Astrophysics Data System (ADS)

We demonstrated an ultra-broadband, polarization-insensitive, and wide-angle metamaterial absorber for terahertz (THz) frequencies using arrays of truncated pyramid unit structure made of metal-dielectric multilayer composite. In our design, each sub-layer behaving as an effective waveguide is gradually modified in their lateral width to realize a wideband response by effectively stitching together the resonance bands of different waveguide modes. Experimentally, our five layer sample with a total thickness 21 ?m is capable of producing a large absorptivity above 80% from 0.7 to 2.3 THz up to the maximum measurement angle 40°. The full absorption width at half maximum of our device is around 127%, greater than those previously reported for THz frequencies. Our absorber design has high practical feasibility and can be easily integrated with the semiconductor technology to make high efficient THz-oriented devices.

Zhu, Jianfei; Ma, Zhaofeng; Sun, Wujiong; Ding, Fei; He, Qiong; Zhou, Lei; Ma, Yungui

2014-07-01

282

Compressed Wideband Spectrum Sensing Based on Discrete Cosine Transform  

PubMed Central

Discrete cosine transform (DCT) is a special type of transform which is widely used for compression of speech and image. However, its use for spectrum sensing has not yet received widespread attention. This paper aims to alleviate the sampling requirements of wideband spectrum sensing by utilizing the compressive sampling (CS) principle and exploiting the unique sparsity structure in the DCT domain. Compared with discrete Fourier transform (DFT), wideband communication signal has much sparser representation and easier implementation in DCT domain. Simulation result shows that the proposed DCT-CSS scheme outperforms the conventional DFT-CSS scheme in terms of MSE of reconstruction signal, detection probability, and computational complexity. PMID:24526894

Wang, Yulin; Zhang, Gengxin

2014-01-01

283

Narrowband and wideband characterisation of satellite mobile/PCN channel  

NASA Technical Reports Server (NTRS)

This paper presents models characterizing satellite mobile channel. Statistical narrowband models based on the CSER high elevation angle channel measurement campaign are reported. Such models are understood to be useful for communication system simulations. It has been shown from the modelling results that for the mobile satellite links at high elevation angles line-of-sight (LOS) signal is available most of the time, even under the heavy shadowing conditions. Wideband measurement campaign which CSER is about to undertake, and subsequently the modelling approach to be adopted is also discussed. It is noted that a wideband channel model is expected to provide a useful tool in investigating CDMA applications.

Butt, G.; Parks, M. A. N.; Evans, B. G.

1995-01-01

284

An accelerator-based wireless sensor network processor in 130nm CMOS Mark Hempstead, Gu-Yeon Wei, David Brooks  

E-print Network

An accelerator-based wireless sensor network processor in 130nm CMOS Mark Hempstead, Gu-Yeon Wei that characterize wireless sensor network workloads. The system employs application specific hardware accelerators processor, heterogeneous hardware accelerators, and application-controlled VDD gating. Networks of ultra

Hempstead, Mark

285

Digitally-Assisted Mixed-Signal Wideband Compressive Sensing  

E-print Network

FOM beats the FOM of the high speed state-of-the-art Nyquist ADCs by 2-3 times. The proposed mixed-signal compressive sensing system can be applied in various fields. In particular, its applications for wideband spectrum sensing for cognitive radios...

Yu, Zhuizhuan

2012-07-16

286

Prospector: Multiscale Energy Measurement of Networked Embedded Systems with Wideband  

E-print Network

-sipping sleep states. Thus the power supply signals have wideband spec- tra. In addition, due to noise, uniform power, and tethered systems are now expected to use minimum energy in numerous sleep and active states calibration, maintenance and recovery involve significant cost, perhaps the largest component of life

287

Wide-band array signal processing via spectral smoothing  

NASA Technical Reports Server (NTRS)

A novel algorithm for the estimation of direction-of-arrivals (DOA) of multiple wide-band sources via spectral smoothing is presented. The proposed algorithm does not require an initial DOA estimate or a specific signal model. The advantages of replacing the MUSIC search with an ESPRIT search are discussed.

Xu, Guanghan; Kailath, Thomas

1989-01-01

288

Wide-band negative permeability of nonlinear metamaterials  

E-print Network

Wide-band negative permeability of nonlinear metamaterials Mikhail Lapine1 , Ilya Shadrivov2 & Yuri frequency range where metamaterial possesses negative effective permeability. This can be achieved by employing a nonlinear response of metamaterials. We demonstrate that, with an appropriate design

289

Band-partitioned sidelobe canceller for a wideband radar  

Microsoft Academic Search

A generic electronic counter-counter measure (ECCM) system consisting of band-partitioned (BP) sidelobe canceller (SLC) is investigated for wideband radar. This paper describes trade-off studies performed on the BP digital SLC and identifies techniques and parameters that are capable of providing improved cancellation performance.

Feng-ling C. Lin; Karl Gerlach; Michael L. Picciolo

2003-01-01

290

A wideband C-shaped vertical patch antenna  

Microsoft Academic Search

A wideband vertical patch antenna (VPA) is depicted, which is devised from a single circular vertical patch. Without increasing the projection area, a C-shaped proximity-coupled fed VPA with 40% bandwidth and over 6 dBi gain across entire frequency band is designed and tested. Stable and broadside patterns are maintained across the matching band.

Ka-lam Lau; Kwai-man Luk; Kai-fong Lee

2006-01-01

291

Wideband radio propagation modeling for indoor geolocation applications  

Microsoft Academic Search

A framework for statistical modeling of the wideband characteristics of the frequency-selective fading multipath indoor radio channel for geolocation applications is presented. Multipath characteristics of the channel are divided into three classes according to availability and the strength of the direct line of sight (DLOS) path with respect to the other paths. Statistics of the error in estimating the time

Kaveh Pahlavan; Prashant Krishnamurthy; A. Beneat

1998-01-01

292

A note on the wide-band Gaussian broadcast channel  

NASA Astrophysics Data System (ADS)

The observations of Posner (1983) that on a wideband Gaussian broadcast channel ordinary time-shared coding performs almost as well as broadcast coding are investigated. A quantitative version of Posner's results is derived. A numerical example comparing the performance of broadcast coding and time-shared coding for a Gaussian broadcast channel model is presented.

McEliece, Robert J.; Swanson, Laif

1987-04-01

293

Archiving of Wideband Plasma Wave Data  

NASA Technical Reports Server (NTRS)

Beginning with the third year of funding, we began a more ambitious archiving production effort, minimizing work on new software and concentrating on building representative archives of the missions mentioned above, recognizing that only a small percentage of the data from any one mission can be archived with reasonable effort. We concentrated on data from Dynamics Explorer and ISEE 1, archiving orbits or significant fractions of orbits which attempt to capture the essence of the mission and provide data which will hopefully be sufficient for ongoing and new research as well as to provide a reference to upcoming and current ISTP missions which will not fly in the same regions of space as the older missions and which will not have continuous wideband data. We archived approximately 181 Gigabytes of data, accounting for some 1582 hours of data. Included in these data are all of the AMPTE chemical releases, all of the Spacelab 2/PDP data obtained during the free-flight portion of its mission, as well as significant portions of the S3, DE-1, Imp-6, Hawkeye, Injun 5, and ISEE 1 and 2 data sets. Table 1 summarizes these data. All of the data archived are summarized in gif-formatted images of frequency-time spectrograms which are directly accessible via the internet. Each of the gif files are identified by year, day, and time as described in the Web page. This provides a user with a specific date/time in mind a way of determining very quickly if there is data for the interval in question and, by clicking on the file name, browsing the data. Alternately, a user can browse the data for interesting features and events simply by viewing each of the gif files. When a user finds data of interest, he/she can notify us by email of the time period involved. Based on the user's needs, we can provide data on a convenient medium or by ftp, or we can mount the appropriate data and provide access to our analysis tools via the network. We can even produce products such as plots or spectrograms in hardcopy form based on the specific request of the user.

Kurth, William S.

1997-01-01

294

Origin of wide-band IP type II bursts  

NASA Astrophysics Data System (ADS)

Context. Different types of interplanetary (IP) type II bursts have been observed, where the more usual ones show narrow-band and patchy emissions, sometimes with harmonics, and which at intervals may disappear completely from the dynamic spectrum. The more unusual bursts are wide-band and diffuse, show no patches or breaks or harmonic emission, and often have long durations. Type II bursts are thought to be plasma emission, caused by propagating shock waves, but a synchrotron-emitting source has also been proposed as the origin for the wide-band type IIs. Aims: Our aim is to find out where the wide-band IP type II bursts originate and what is their connection to particle acceleration. Methods: We analyzed in detail 25 solar events that produced well-separated, wide-band IP type II bursts in 2001-2011. Their associations to flares, coronal mass ejections (CMEs), and solar energetic particle events (SEPs) were investigated. Results: Of the 25 bursts, 18 were estimated to have heights corresponding to the CME leading fronts, suggesting that they were created by bow shocks ahead of the CMEs. However, seven events were found in which the burst heights were significantly lower and which showed a different type of height-time evolution. Almost all the analyzed wide-band type II bursts were associated with very high-speed CMEs, originating from different parts of the solar hemisphere. In terms of SEP associations, many of the SEP events were weak, had poor connectivity due to the eastern limb source location, or were masked by previous events. Some of the events had precursors in specific energy ranges. These properties and conditions affected the intensity-time profiles and made the injection-time-based associations with the type II bursts difficult to interpret. In several cases where the SEP injection times could be determined, the radio dynamic spectra showed other features (in addition to the wide-band type II bursts) that could be signatures of shock fronts. Conclusions: We conclude that in most cases (in 18 out of 25 events) the wide-band IP type II bursts can be plasma emission, formed at or just above the CME leading edge. The results for the remaining seven events might suggest the possibility of a synchrotron source. These events, however, occurred during periods of high solar activity, and coronal conditions affecting the results of the burst height calculations cannot be ruled out. The observed wide and diffuse emission bands may also indicate specific CME leading edge structures and special shock conditions. Figures 2-26 and Table 4 are available in electronic form at http://www.aanda.org

Pohjolainen, S.; Allawi, H.; Valtonen, E.

2013-10-01

295

A power and data link for a wireless-implanted neural recording system.  

PubMed

A wireless cortical neural recording system with a miniature-implanted package is needed in a variety of neuroscience and biomedical applications. Toward that end, we have developed a transcutaneous two-way communication and power system for wireless neural recording. Wireless powering and forward data transmission (into the body) at 1.25 Mbps is achieved using a frequency-shift keying modulated class E converter. The reverse telemetry (out of the body) carrier frequency is generated using an integer-N phase-locked loop, providing the necessary wideband data link to support simultaneous reverse telemetry from multiple implanted devices on separate channels. Each channel is designed to support reverse telemetry with a data rate in excess of 3 Mbps, which is sufficient for our goal of streaming 16 channels of raw neural data. We plan to incorporate this implantable power and telemetry system in a 1-cm diameter single-site cortical neural recording implant. PMID:22922687

Rush, Alexander D; Troyk, Philip R

2012-11-01

296

Distributed MAC protocol for networks with multipacket reception capability and spatially distributed nodes  

E-print Network

The physical layer of future wireless networks will be based on novel radio technologies such as Ultra-Wideband (UWB) and Multiple-Input Multiple-Output (MIMO). One of the important capabilities of such technologies is the ...

Celik, Guner Dincer

2007-01-01

297

Frequency-aware rate adaptation and MAC protocol  

E-print Network

There has been burgeoning interest in wireless technologies that can use wider frequency spectrum. Technology advances, such as 802.11n and ultra-wideband (UWB), are pushing toward wider frequency bands. The analog-to-digital ...

Rahul, Hariharan Shankar

298

Ubiquitous Wireless Interworking (UWIN)  

E-print Network

generation wireless infrastructure? Must lower costs for service providers throughout the life-cycle (install of star- cell? #12;Research Questions cont. Opportunity to "think outside of the box" with wireless the service provider verified, tested, and uploaded? #12;Star Cell Increase cell size via wireless extensions

Gruner, Daniel S.

299

Wireless sensor prototype platform  

Microsoft Academic Search

This paper presents the design and performance measurements of a wireless sensor prototype platform (UbiSensor). UbiSensor combines techniques used in wireless microsensors and radio frequency identification (RFID) resulting a wireless sensor having sensing, data processing, network protocol execution, and energy scavenging capabilities. The platform design is driven by energy consumption minimization of given tasks. A commercially available microcontroller, low power

Mikko Kohvakka; Marko Hannikainen; T. D. Hamalainen

2003-01-01

300

Wireless Sensor Networks  

Microsoft Academic Search

The confluence of inexpensive wireless communication, computation, and sensing has created a new generation of smart devices. Using tens to thousands of these devices in self-organizing networks has created a new technology referred to as wireless sensor networks. This article gives an overview of the wireless sensor networks.

John A. Stankovic

2008-01-01

301

Short-Range Ultra-Wideband Systems UMass Antenna Lab USC UltRa Lab UC Berkeley BWRC  

E-print Network

directions that may be interesting UWB Antenna Theory and Design David Pozar Electrical and Computer. Pozar, "Closed-form approximations for link loss in an UWB radio system using small antennas", IEEE waveforms implemented by using 4-bit quantization result in reasonably good link performance. D. M. Pozar

Southern California, University of

302

Cryogenic wide-band ultra-low-noise IF amplifiers operating at ultra-low DC power  

Microsoft Academic Search

This paper describes cryogenic broad-band amplifiers with very low power consumption and very low noise for the 4-8-GHz frequency range. At room temperature, the two-stage InP-based amplifier has a gain of 27 dB and a noise temperature of 31 K with a power consumption of 14.4 mW per stage, including bias circuitry. When cooled to 15 K, an input noise

Niklas Wadefalk; Anders Mellberg; I. Angelov; M. E. Barsky; S. Bui; E. Choumas; R. W. Grundbacher; E. L. Kollberg; R. Lai; N. Rorsman; P. Starski; J. Stenarson; D. C. Streit; H. Zirath

2003-01-01

303

Highly Stable Wideband Microwave Extraction by Synchronizing Widely Tunable Optoelectronic Oscillator with Optical Frequency Comb  

PubMed Central

Optical frequency combs (OFCs), based on mode-locked lasers (MLLs), have attracted considerable attention in many fields over recent years. Among the applications of OFCs, one of the most challenging works is the extraction of a highly stable microwave with low phase noise. Many synchronisation schemes have been exploited to synchronise an electronic oscillator with the pulse train from a MLL, helping to extract an ultra-stable microwave. Here, we demonstrate novel wideband microwave extraction from a stable OFC by synchronising a single widely tunable optoelectronic oscillator (OEO) with an OFC at different harmonic frequencies, using an optical phase detection technique. The tunable range of the proposed microwave extraction extends from 2?GHz to 4?GHz, and in a long-term synchronisation experiment over 12 hours, the proposed synchronisation scheme provided a rms timing drift of 18?fs and frequency instabilities at 1.2 × 10?15/1?s and 2.2 × 10?18/10000 s. PMID:24336459

Hou, D.; Xie, X. P.; Zhang, Y. L.; Wu, J. T.; Chen, Z. Y.; Zhao, J. Y.

2013-01-01

304

Fiber laser sensors: enabling the next generation of miniaturized, wideband marine sensors  

NASA Astrophysics Data System (ADS)

Fiber laser strain sensors achieve fundamentally limited strain resolution, resulting in their ability to resolve axial fiber displacements at the sub-femtometer level. This ultra-high resolution enables the development of miniaturized sensors capable of achieving the performance necessary for high resolution marine sensing. The reduction in size also facilitates an increased operating bandwidth for broadband acoustic transducers. The last decade has seen considerable development of this technology, moving it from a laboratory curiosity to deployable demonstrations. Significant advances have been made in understanding the fundamental properties of erbium fiber laser strain sensors as well as laser multiplexing, signal demodulation and sensor design. This talk will describe the basic properties of fiber laser strain sensors and show how the technical challenges involved in developing deployable, multiplexed arrays of miniature transducers have been overcome. In particular the development of miniature wideband hydrophones, low power DC magnetometers with sub-nT resolution and miniature acoustic vector sensors will be described. Finally, a view towards potential future applications of this technology will be given.

Cranch, G. A.; Miller, G. A.; Kirkendall, C. K.

2011-06-01

305

Wireless Grid: Enabling Ubiquitous Sensor Networks with Wireless Energy Supply  

Microsoft Academic Search

Sensor node life-time limitation in wireless sensor networks has long become an issue, preventing it to become a reliable ubiquitous network. In this paper, a new concept called wireless grid, which includes a fusion of wireless sensor network and wireless power transmission is introduced. By doing this, battery life-time problem can be avoided, hence, providing high network reliability. Wireless power

Ragil Putro Wicaksono; Gia Khanh Tran; Kei Sakaguchi; Kiyomichi Araki

2011-01-01

306

Wireless structural monitoring for homeland security applications  

NASA Astrophysics Data System (ADS)

This paper addresses the development of a robust, low-cost, low power, and high performance autonomous wireless monitoring system for civil assets such as large facilities, new construction, bridges, dams, commercial buildings, etc. The role of the system is to identify the onset, development, location and severity of structural vulnerability and damage. The proposed system represents an enabling infrastructure for addressing structural vulnerabilities specifically associated with homeland security. The system concept is based on dense networks of "intelligent" wireless sensing units. The fundamental properties of a wireless sensing unit include: (a) interfaces to multiple sensors for measuring structural and environmental data (such as acceleration, displacements, pressure, strain, material degradation, temperature, gas agents, biological agents, humidity, corrosion, etc.); (b) processing of sensor data with embedded algorithms for assessing damage and environmental conditions; (c) peer-to-peer wireless communications for information exchange among units(thus enabling joint "intelligent" processing coordination) and storage of data and processed information in servers for information fusion; (d) ultra low power operation; (e) cost-effectiveness and compact size through the use of low-cost small-size off-the-shelf components. An integral component of the overall system concept is a decision support environment for interpretation and dissemination of information to various decision makers.

Kiremidjian, Garo K.; Kiremidjian, Anne S.; Lynch, Jerome P.

2004-07-01

307

Wideband enhancement of television images for people with visual impairments  

NASA Astrophysics Data System (ADS)

Wideband enhancement was implemented by detecting visually relevant edge and bar features in an image to produce a bipolar contour map. The addition of these contours to the original image resulted in increased local contrast of these features and an increase in the spatial bandwidth of the image. Testing with static television images revealed that visually impaired patients (n=35) could distinguish the enhanced images and preferred them over the original images (and degraded images). Most patients preferred a moderate level of wideband enhancement, since they preferred natural-looking images and rejected visible artifacts of the enhancement. Comparison of the enhanced images with the originals revealed that the improvement in the perceived image quality was significant for only 22% of the patients. Possible reasons for the limited increase in perceived image quality are discussed, and improvements are suggested.

Peli, Eli; Kim, Jeonghoon; Yitzhaky, Yitzhak; Goldstein, Robert B.; Woods, Russell L.

2004-06-01

308

An Ultra Low Power Medium Access Control Protocol with the Divided Preamble Sampling  

Microsoft Academic Search

This paper proposes DPS-MAC (Divided Preamble Sampling-MAC), a carrier sense Medium Access Control (MAC) protocol with ultra\\u000a low power operations for wireless sensor networks. Due to battery-operated computing and sensing devices in wireless sensor\\u000a networks, the development of MAC protocols that efficiently reduce power consumption is an important issue. DPS-MAC is a novel\\u000a energy efficient protocol based on sampling preamble

Sangsoon Lim; Youngmin Ji; Jaejoon Cho; An Sunshin

2006-01-01

309

An analog approach to interference suppression in ultra-wideband receivers  

E-print Network

for OTAs in the bandpass filter. The loca- tion of the devices are labeled. . . . . . . . . . . . . . . . . . . . . . 66 50 Building block layout for OTAs in the bandpass filter. The orien- tation of the OTAs and CMFB circuitry are labeled... for OTAs in the bandpass filter. The loca- tion of the devices are labeled. . . . . . . . . . . . . . . . . . . . . . 66 50 Building block layout for OTAs in the bandpass filter. The orien- tation of the OTAs and CMFB circuitry are labeled...

Fischer, Timothy W.

2007-09-17

310

Energy-efficient analog-to-digital conversion for ultra-wideband radio  

E-print Network

In energy constrained signal processing and communication systems, a focus on the analog or digital circuits in isolation cannot achieve the minimum power consumption. Furthermore, in advanced technologies with significant ...

Ginsburg, Brian P. (Brian Paul), 1980-

2007-01-01

311

Investigation of ultra wideband multi-channel dichroic beamsplitters from 0.3 to 52 microns  

NASA Technical Reports Server (NTRS)

The development of a set of multi-channel dichroics which includes a 6 channel dichroic operating over the wavelength region from 0.3 to 52 microns is described. In order to achieve the optimum performance, the optical constraints of PbTe, Ge, and CdTe coatings in the strongly absorptive region have been determined by use of a new iterative method using normal incidence reflectance measurement of the multilayer together with initial values of energy gap and infinite refractive index for the semiconductor model. The design and manufacture of the dichroics is discussed and the final results are presented.

Zhang, K. Q.; Hunneman, R.; Seeley, J. S.; Hawkins, G. J.

1990-01-01

312

Ultra-wideband microwave photonic phase shifter with configurable amplitude response.  

PubMed

We introduce a new principle that enables separate control of the amplitude and phase of an optical carrier, simply by controlling the power of two stimulated Brillouin scattering (SBS) pumps. This technique is used to implement a microwave photonic phase shifter with record performance, which solves the bandwidth limitation of previous gain-transparent SBS-based phase shifters, while achieving unprecedented minimum power fluctuations, as a function of phase shift. We demonstrate 360° continuously tunable phase shift, with less than 0.25 dB output power fluctuations, over a frequency band from 1.5 to 31 GHz, limited only by the measurement equipment. PMID:25361102

Pagani, M; Marpaung, D; Eggleton, B J

2014-10-15

313

Power-efficient ultra wideband LNAs for the world's largest radio telescope  

NASA Astrophysics Data System (ADS)

This paper reports two Low Noise Amplifiers (LNA) for Aperture Array system of the international Square Kilometre Array (SKA) project. LNA design for SKA is a step change in traditional LNA design approach for radio astronomy applications as the defining aspects of performance are low noise along with low power consumption and adequate gain. The LNAs are designed, fabricated and characterised for frequency range of 20 -1000 MHz. One LNA has single ended input to single ended output configuration (LNA1) while the other LNA has balanced input to single ended output (LNA2). The S-parameter, noise figure (NF) and large signal response of the LNAs are measured at room temperature. Both LNAs show flat gain of higher than 30 dB over specified frequency range. Average NF values of LNA1 and LNA2 are 0.55 dB and 0.75 dB respectively. Mixed mode S-parameter response based on theoretical analysis of differential configuration is presented. The LNAs have exceptionally low power consumption of less than 25 mW; 20 times lower than the other reported LNAs available for the SKA and also covering complete frequency band with less than 1 dB NF. Therefore implication of these LNAs is a significant step forward as the projected number of LNAs required for the lower frequency band of SKA Aperture Array system is 5,600,000 (Dewdney et al., Proc. IEEE 97(8), 1482-1496, 2009; Faulkner et al. 2010).

Panahi, M.; Bhaumik, S.; George, D.

2014-10-01

314

Group delay in THz spectroscopy with ultra-wideband log-spiral antennae  

E-print Network

We report on the group delay observed in continuous-wave terahertz spectroscopy based on photomixing with phase-sensitive homodyne detection. We discuss the different contributions of the experimental setup to the phase difference \\Delta\\phi(\

Langenbach, M; Mayorga, I Cámara; Deninger, A; Thirunavukkuarasu, K; Hemberger, J; Grüninger, M

2014-01-01

315

Energy efficient ultra-wideband radio transceiver architectures and receiver circuits  

E-print Network

Energy efficient short-range radios have become an active research area with proliferation of portable electronics. A critical specification for radio efficiency is energy/bit. The FCC has allocated the 3.1-10.6 GHz band ...

Lee, Fred S. (Fred Shung-Neng), 1979-

2007-01-01

316

The National Geoelectromagnetic Facility - an open access resource for ultra wideband electromagnetic geophysics (Invited)  

NASA Astrophysics Data System (ADS)

At present, the US academic community has access to two national electromagnetic (EM) instrument pools that support long-period magnetotelluric (MT) equipment suitable for crust-mantle scale studies. The requirements of near surface geophysics, hydrology, glaciology, as well as the full range of crust and mantle investigations require development of new capabilities in data acquisition with broader frequency bandwidth than these existing units, increased instrument numbers, and concomitant developments in 3D/4D data interpretation. NSF Major Research Instrumentation support has been obtained to meet these requirements by developing an initial set of next-generation instruments as a National Geoelectromagnetic Facility (NGF), available to all PIs on a cost recovery basis, and operated by Oregon State University (OSU). In contrast to existing instruments with data acquisition systems specialized to operate within specific frequency bands and for specific electromagnetic methods, the NGF model "Zen/5" instruments being co-developed by OSU and Zonge Research and Engineering Organization are based on modular receivers with a flexible number of digital and analog input channels, designed to acquire EM data at dc, and from frequencies ranging from micro-Hz to MHz. These systems can be deployed in a compact, low power configuration for extended deployments (e.g. for crust-mantle scale experiments), or in a high frequency sampling mode for near surface work. The NGF is also acquiring controlled source EM transmitters, so that investigators may carry out magnetotelluric, audio-MT, radiofrequency-MT, as well as time-domain/transient EM and DC resistivity studies. The instruments are designed to simultaneously accommodate multiple electric field dipole sensors, magnetic fluxgates and induction coil sensors. Sample rates as high as 2.5 MHz with resolution between 24 and 32 bits, depending on sample rate, are specified to allow for high fidelity recording of waveforms. The NGF is accepting instrument use requests from investigators planning electromagnetic surveys via webform submission on its web site ngf.coas.oregonstate.edu. The site is also a port of entry to request access to the 46 long period magnetotelluric instruments also operated by OSU as national instrument pools. Cyberinfrastructure support is available to investigators, including field computers, EM data processing software, and access to a hybrid CPU-GPU parallel computing environment, currently configured with dual Intel Westmere hexacore CPUs and 960 NVidia Tesla and 1792 Nvidia Fermi GPU cores. The capabilities of the Zen/5 receivers will be presented, with examples of data acquired from a recent shallow water marine controlled source experiment conducted in coastal Oregon as part of an effort to locate a buried submarine pipeline, using a 1.1 KW 256 Hz signal source imposed on the pipeline from shore. A Zen/5 prototype instrument, modified for marine use through support by the Oregon Wave Energy Trust, demonstrated the marine capabilities of the NGF instrument design.

Schultz, A.; Urquhart, S.; Slater, M.

2010-12-01

317

An Ultra-Wideband Cross-Correlation Radiometer for Mesoscopic Experiments  

Microsoft Academic Search

We have designed, built and tested a cross-correlation radiometer for detecting statistical order in the quantum fluctuations of mesoscopic experiments at sub-Kelvin temperatures. Our system utilizes a fully analog front-end--operating over the X- and Ku-bands (8 to 18 GHz)--for computing the cross-correlation function. Digital signal processing techniques are used to provide robustness against instrumentation drifts and offsets. The economized version

Ryan Toonen; Cyrus Haselby; Hua Qin; Mark Eriksson; Robert Blick

2007-01-01

318

An N-Bit Digitally Variable Ultra Wideband Pulse Generator for GPR and UWB Applications  

E-print Network

has found military applications such as ground penetrating radar (GPR), wall penetrating radar, secure. Particularly, in UWB ground penetrating radar, a digitally tunable pulse generator allows the pulse width on the resolution of the radar. If the impulse radio is used as GPR to provide high penetration depth, higher pulse

Yanikoglu, Berrin

319

Ultra-Wideband, Low-Power, Inductorless, 3.1–4.8 GHz, CMOS VCO  

Microsoft Academic Search

A low-power, inductorless, UWB CMOS voltage controlled oscillator is designed in 0.18 ?m CMOS technology targeting to a UWBFM\\u000a transmitter application. The VCO is a Double-Cross-Coupled Multivibrator and generates output frequencies ranging from 1.55 GHz\\u000a to 2.4 GHz. A low-power frequency doubler based on a Gilbert cell, which operates in weak inversion, doubles the VCO tuning\\u000a range from 3.1 GHz to 4.8 GHz. The proportionality between

Athanasios Tsitouras; Fotis Plessas

2011-01-01

320

Ultra-Wideband UHF Microstrip Array for GeoSAR Application  

NASA Technical Reports Server (NTRS)

GeoSAR is a program sponsored by DARPA (Defense Advanced Research Projects Agency) and NASA (National Aeronautics and Space Administration) to develop an airborne, radar- based, commercial terrain mapping system for identification of geologic, seismic, and environmental information, it has two (dual-band at X and UHF) state-of-the-art interferometric synthetic aperture radar (SAR) ground mapping systems. The UHF interferometric system is utilized to penetrate the vegetation canopy and obtain true ground surface height information, while the Xband system will provide capability of mapping the top foliage surface. This paper presents the UHF antenna system where the required center frequency is 350 MHz with a 160 MHz of bandwidth (46% from 270 MHz to 430 MHz). The antenna is required to have dual-linear polarization with a peak gain of 10 dB at the center frequency and a minimum gain of 8 dB toward two ends of the frequency band. One of the most challenging tasks, in addition to achieving the 46% bandwidth, is to develop an antenna with small enough size to fit in the wing-tip pod of a Gulfstream II aircraft.

Thomas, Robert F.; Huang, John

1998-01-01

321

The Irregular-Shaped Fractal Antennas for Ultra Wideband Radio Systems  

Microsoft Academic Search

This paper proposes a novel design of a multiband fractal antenna of irregular shape using two-dimensional fractal clusters. The algorithm of generating fully reproducible fractal clusters is developed. The multiband behavior of the fractal-cluster based antennas is studied by means of numerical analysis. In comparison to regular-shaped fractal antennas more frequency bands and better matching are achieved. The spatial-frequency antenna

S. V. Krupenin; V. V. Kolesov; A. A. Potapov; N. G. Petrova

2006-01-01

322

CMOS Integrated Circuit Design for Ultra-Wideband Transmitters and Receivers  

E-print Network

makes the CMOS circuit capable of handling signal at multi-giga herz. However, some design challenges still remain to be solved. Unlike regular narrow band signal, the UWB signal is discrete pulse instead of continuous wave (CW), which results...

Xu, Rui

2010-10-12

323

Wideband Circularly Polarized Patch Antenna Using Broadband Baluns  

Microsoft Academic Search

A novel 90deg broadband balun comprising a broadband 90deg Schiffman phase shifter is introduced as a means of enhancing the wideband circular polarization performance of dual-fed type microstrip antennas. The proposed 90deg broadband balun delivers good impedance matching, balanced power splitting and consistent 90deg (plusmn5deg) phase shifting, across a wide bandwidth (~57.5%). A circular patch antenna utilizing the proposed 90deg

Yong-Xin Guo; Kah-Wee Khoo; Ling Chuen Ong

2008-01-01

324

A new wide-band 180° planar phase shifter network  

Microsoft Academic Search

A new wide-band 180° micro-strip phase shifter network on TP-2 is presented in this paper. The network is composed of coupled lines and double 45° open and short stubs, which are shunted at the edge points of the main line respectively. To demonstrate the design methodology, a new structure 180° phase shifter network, operated at 3.5~5.5GHz, were designed and fabricated

Xu-min Yu; Juan Wang; Xiaohong Tang

2009-01-01

325

Tentative chip decision-feedback equalizer for multicode wideband CDMA  

Microsoft Academic Search

We investigate a chip-level minimum mean-square-error (MMSE) decision-feedback equalizer (DFE) for the downlink receiver of multicode wideband code-division multiple-access systems over frequency-selective channels. First, the MMSE per symbol achievable by an optimal DFE is derived, assuming that all interchip interference (ICI) of the desired user can be eliminated. The MMSE of DFE is always less than or at most equal

J. Yang; Y. Li

2005-01-01

326

Low-Voltage Analog Circuits Based on Wideband Capacitive Coupling  

Microsoft Academic Search

A technique for wideband low-voltage analog circuit operation based on capacitive signal coupling is discussed. Circuits based on this technique do not show the GB degradation of other low-voltage approaches based on floating-gate transistors. The technique is validated with simulations of a new CMOS mixer and experimental results of a test chip in a 0.5 µm CMOS technology.

Jaime Ramírez-Angulo; Carlos Urquidi; Ramon G. Carvajal; Antonio Torralba; Antonio J. Lopez-Martin

2003-01-01

327

An overview of CDMA evolution toward wideband CDMA  

Microsoft Academic Search

Third-generation mobile radio networks, often dubbed as 3G, have been under intense research and discussion recently and will emerge around the year 2000. In the International Telecommunications Union (ITU), third generation networks are called International Mobile Telecommunications-2000 (IMT-2000), and in Europe, Universal Mobile Telecommunications System (UMTS). IMT-2000 will provide a multitude of services, especially multimedia and high-bit-rate packet data. Wideband

Ramjee Prasad; Tero Ojanpera

1998-01-01

328

Green HgCl-laser with wideband optical pumping  

NASA Astrophysics Data System (ADS)

A photodissociation laser using the B-X electron transition in mercury chloride (wavelengths, 558 and 559 nm) is reported. The laser employs wideband optical pumping of HgCl2 vapors by a thermal plasma emission. The laser pulse energy reaches 2.1 J with a duration of 7.6 microsec; the efficiency of the laser with respect to the stored energy is 0.1 percent.

Bazhulin, S. P.; Basov, N. G.; Bugrimov, S. N.; Zuyev, V. S.; Kamrukov, A. S.; Kashnikov, G. N.; Kozlov, N. P.; Ovchinnikov, P. A.; Opekan, A. G.; Orlov, V. K.

1987-04-01

329

A green mercury chloride laser with wideband optical pumping  

NASA Astrophysics Data System (ADS)

A photodissociation laser using the B-X electron transition in mercury chloride (wavelengths, 558 and 559 nm) is reported. The laser employs wideband optical pumping of HgCl2 vapors by a thermal plasma emission. The laser pulse energy reaches 2.1 J with a duration of 7.6 microsec; the efficiency of the laser with respect to the stored energy is 0.1 percent.

Bazhulin, S. P.; Basov, N. G.; Bugrimov, S. N.; Zuev, V. S.; Kamrukov, A. S.

1986-06-01

330

Optimizing Linear Dispersion Codes for Wideband MIMO Systems  

Microsoft Academic Search

We consider the problem of designing space-time- frequency linear dispersion (LD) codes in wideband multiple- input multiple-output (MIMO) antenna systems employing orthogonal-frequency-division-multiplexing (OFDM). Three design methods are presented and discussed, which involve: (1) minimizing the average block error rate, (2) maximizing the ergodic mutual information, and (3) a two-step procedure considering the optimization of the mutual information as well as

Luca Venturino; Narayan Prasad; Xiaodong Wang; Mohammad Madihian

2007-01-01

331

MMSE diversity combining for wide-band digital cellular radio  

Microsoft Academic Search

A study of minimum mean-square error (MMSE) diversity combining for wide-band digital cellular radio, designed to combat intersymbol interference (ISI) caused by frequency selective fading is outlined. The systems analyzed use binary phase-shift keying (BPSK), quarternary phase-shift keying (QPSK) or 16-level quadrature amplitude modulation (16-QAM) with cosine rolloff spectral shaping, and space diversity with selection, maximal ratio or MMSE combining.

Martin V. Clark; Larry J. Greenstein; William K. Kennedy; Mansoor Shafi

1992-01-01

332

An accelerator-based wireless sensor network processor in 130nm CMOS  

Microsoft Academic Search

Networks of ultra-low-power nodes capable of sensing, computa- tion, and wireless communication have applications in medicine, science, industrial automation, and security. Over the past few years, deployments of wireless sensor networks (WSNs) have uti- lizednodesbasedonoff-the-shelfgeneralpurposemicrocontrollers. Reducing power consumption requires the development of System- on-chip (SoC) implementations that must provide both energy effi- ciency and adequate performance to meet the demands

Mark Hempstead; Gu-yeon Wei; David Brooks

2009-01-01

333

Novel paper-based inkjet-printed antennas and wireless sensor modules  

Microsoft Academic Search

In this paper, inkjet-printed flexible antennas fabricated on paper substrates are introduced as a system-level solution for ultra-low-cost mass production of UHF radio frequency identification (RFID) tags and wireless sensor nodes (WSN) in an approach that could be easily extended to other microwave and wireless applications. The presented material is a review of our grouppsilas major reported milestones in this

M. M. Tentzeris

2008-01-01

334

Wideband Phased Array & Rectenna Design and Modeling for Wireless Power Transmission  

E-print Network

-patch, broadband, dual-polarized, aperture-fed antenna is tested, and some adjustments are made to improve performance. The design goal is to obtain a 3 GHz bandwidth centered at 10 GHz for each polarization. Once the single-element design is finalized.... An aperture-coupled, high-gain, single-patch rectenna is also designed and measured. This rectenna is modeled using the presented method, and the simulation shows good agreement with the measured results. This further validates the proposed modeling...

Hansen, Jonathan Noel

2012-02-14

335

A Wideband Body-Enabled Millimeter-Wave Transceiver for Wireless Network-an-Chip  

E-print Network

-enabled circuit design techniques were implemented: Forward body-bias was used in the low-noise amplifier (LNA that the receiver has a double-sideband noise figure of less than 6 dB, and a peak gain of 20.5 dB, while exchange between distant cores entails high latency and power consumption. Different revolutionary

Pande, Partha Pratim

336

Wideband LTE Power Amplifier with Integrated Novel Analog Pre-Distorter Linearizer for Mobile Wireless Communications  

PubMed Central

For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA’s power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics. PMID:25033049

Uthirajoo, Eswaran; Ramiah, Harikrishnan; Kanesan, Jeevan; Reza, Ahmed Wasif

2014-01-01

337

Wideband Aural Acoustic Absorbance Predicts Conductive Hearing Loss in Children  

PubMed Central

Objective This study tested the hypothesis that wideband aural absorbance predicts conductive hearing loss (CHL) in children medically classified as having otitis media with effusion. Design Absorbance was measured in the ear canal over frequencies from 0.25 to 8 kHz at ambient pressure or as a swept tympanogram. CHL was defined using criterion air-bone gaps of 20, 25 and 30 dB at octaves from 0.25 to 4 kHz. A likelihood-ratio predictor of CHL was constructed across frequency for ambient absorbance and across frequency and pressure for absorbance tympanometry. Performance was evaluated at individual frequencies and for any frequency at which a CHL was present. Study Sample Absorbance and conventional 226-Hz tympanograms were measured in children of age 3 to 8 years with CHL and with normal hearing. Results Absorbance was smaller at frequencies above 0.7 kHz in the CHL group than the control group. Based on the area under the receiver operating characteristic curve, wideband absorbance in ambient and tympanometric tests were significantly better predictors of CHL than tympanometric width, the best 226-Hz predictor. Accuracies of ambient and tympanometric wideband absorbance did not differ. Conclusions Absorbance accurately predicted CHL in children and was more accurate than conventional 226-Hz tympanometry. PMID:23072655

Keefe, Douglas H.; Sanford, Chris A.; Ellison, John C.; Fitzpatrick, Denis F.; Gorga, Michael P.

2013-01-01

338

Design of a wideband excitation source for fast bioimpedance spectroscopy  

NASA Astrophysics Data System (ADS)

Multi-frequency-one-time (MFOT) measurement of bioimpedance spectroscopy (BIS) can greatly reduce measurement time and grasp the transient physiological status of a living body compared with the traditional one-frequency-one-time (OFOT) measurement technology, and a wideband excitation source mixed with multiple frequencies is a crucial part of MFOT measurement of BIS. This communication describes a design of a wideband excitation source. Firstly, a multi-frequency mixed (MFM) signal containing seven primary harmonics is synthesized based on Walsh functions, which is a periodical and rectangular signal and whose 68.9% of the energy is homogeneously distributed on its seven 2nth primary harmonics. Then the MFM signal is generated by a field programmable gate array (FPGA), and a unipolar-to-bipolar convertor (UBC) is designed to convert the unipolar signal into bipolar signal. Finally, the bipolar MFM signal is driven by a voltage-controlled current source (VCCS). A 2R-1C series model is adopted as the load of the VCCS, and the simulated voltage response on the load is obtained based on the theoretical analysis. Experiments show that the practical waveform on the load matches well with the theoretical analysis, which indicates that the VCCS has a good performance on the MFM signal. The design of the wideband excitation source establishes a good foundation for fast measurement of BIS.

Yang, Yuxiang; Kang, Minhang; Lu, Yong; Wang, Jian; Yue, Jing; Gao, Zonghai

2011-01-01

339

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra- lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2003-10-31

340

SiGe receiver front ends and flip-chip integrated wideband antennas for millimeter-wave passive imaging  

E-print Network

SiGe wideband 77-GHz and 94-GHz front end receivers with integrated antennas for passive imaging have been designed and characterized. These front end systems exhibit wideband performance with the highest gain and lowest ...

Powell, Johnna, 1980-

2009-01-01

341

47 CFR 90.1432 - Conditions for waiver to allow limited and temporary wideband operations in the 700 MHz public...  

Code of Federal Regulations, 2011 CFR

...operations in the 700 MHz public safety spectrum. 90.1432 Section 90.1432 ...operations in the 700 MHz public safety spectrum. (a) Wideband operations in the 700 MHz Public Safety spectrum. Wideband operations are...

2011-10-01

342

47 CFR 90.1432 - Conditions for waiver to allow limited and temporary wideband operations in the 700 MHz public...  

Code of Federal Regulations, 2010 CFR

...operations in the 700 MHz public safety spectrum. 90.1432 Section 90.1432 ...operations in the 700 MHz public safety spectrum. (a) Wideband operations in the 700 MHz Public Safety spectrum. Wideband operations are...

2010-10-01

343

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; summary of pertinent information from Russian ultra-lightweight cement literature review; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job.

Fred Sabins

2001-07-18

344

Wideband, high efficiency optical modulator requires less than 10 watts drive power  

NASA Technical Reports Server (NTRS)

Wideband optical modulation system operates with less than 10-watts drive power. It consists of an optical modulator and transistorized driver that combines small cross-section potassium dideuterium phosphate crystals with laser beam-condensing optics. Optical modulation systems may serve importantly in future space wideband communication systems.

Becknell, W. E.; Rattman, W. J.; Yap, B. K.

1967-01-01

345

Development of Tilted Toroidal Beam Wideband Transducer Using Quadrature Phase Shift Keying for Underwater Acoustic Communication  

Microsoft Academic Search

To achieve high-speed underwater acoustic communication, a wideband transducer suitable for use in the vicinity of the sea bottom was developed. With the wideband characteristic maintained, the beam can be formed by combining two free-flooded rings. The characteristic of the developed transducer was measured. An excellent characteristic was obtained within an angular range from the horizontal to 30° elevation. Also,

Hiroshi Ochi; Tetsuo Fukuchi

2007-01-01

346

Design of a Compact Wideband Log-Periodic-Dipole-Array Antenna Using WIPL-D Software  

E-print Network

Design of a Compact Wideband Log-Periodic-Dipole-Array Antenna Using WIPL-D Software Bassem H software WIPL-D is used to optimize the design of a compact wideband log periodic dipole array antenna are introduced. A 26% reduction in size is achieved for the same desired bandwidth and gain. Keywords: Log-Periodic

Elsherbeni, Atef Z.

347

Target Simulator to Calibrate Wideband Radar in Measuring the Internal Layers of the Greenland Ice Sheet  

Microsoft Academic Search

We developed a hardware target simulator for measuring the system response and testing of an airborne wideband radar that operates over the frequency range 600-900 MHz to map the near-surface internal layers in glacial ice. It uses optical and microwave delay lines for evaluating and optimizing the performance of the wideband radar in the continental United States without expensive field

B. Parthasarathy; T. Plummer; P. Kanagaratnam

2004-01-01

348

K-DELTA-1-SIGMA MODULATORS FOR WIDEBAND ANALOG-TO-DIGITAL Vishal Saxena  

E-print Network

K-DELTA-1-SIGMA MODULATORS FOR WIDEBAND ANALOG-TO-DIGITAL CONVERSION by Vishal Saxena Title: K-Delta-1-Sigma Modulators for Wideband Analog-to-Digital Conversion Date of Final Oral adviser Dr. Jake Baker for the opportunity to research on delta-sigma data con- verters

Baker, R. Jacob

349

Wideband two-dimensional and multiple beam phased arrays and microwave applications using piezoelectric transducers  

E-print Network

-cost and wideband antenna systems. The main areas of study are microwave devices controlled piezoelectric transducers (PETs) and wideband baluns and balanced microwave circuits using parallel-strip lines. Some focus has also been given to the design of Rotman lens...

Kim, Sang Gyu

2005-08-29

350

Absolute calibration of stellar observations in wide-band photometric systems by the striplamp energy standard  

Microsoft Academic Search

A method for obtaining the instrumental stellar magnitudes outside the Earth's atmosphere in wide-band photometric systems is described. This method is based on spectrophotometric energy distribution data in stellar spectra calibrated by the striplamp energy standard. Response curves and zero-points of wide-band magnitudes are also obtained by direct comparison with the striplamp energy standard.

V. V. Novikov

1989-01-01

351

Binaural detection with narrowband and wideband reproducible noise maskers: I. Results for human  

E-print Network

Binaural detection with narrowband and wideband reproducible noise maskers: I. Results for human October 2001 This study investigated binaural detection of tonal targets 500 Hz using sets of individual masker waveforms with two different bandwidths. Previous studies of binaural detection with wideband

Carney, Laurel H.

352

Binaural detection with narrowband and wideband reproducible noise maskers: II. Results for rabbit  

E-print Network

Binaural detection with narrowband and wideband reproducible noise maskers: II. Results for rabbit Binaural detection with narrowband and wideband noise maskers was examined by using a Pavlovian is inconsistent with models for binaural detection that depend only upon the narrow band of energy centered

Carney, Laurel H.

353

Effects of Consecutive Wideband Tympanometry Trials on Energy Absorbance Measures of the Middle Ear  

ERIC Educational Resources Information Center

Purpose: Wideband acoustic immittance (WAI) is a new technique for assessing middle ear transfer function. It includes energy absorbance (EA) measures and can be acquired with the ear canal pressure varied, known as "wideband tympanometry" (WBTymp). The authors of this study aimed to investigate effects of consecutive WBTymp testing on…

Burdiek, Laina M.; Sun, Xiao-Ming

2014-01-01

354

Power-Efficient Data Propagation Protocols for Wireless Sensor Networks  

Microsoft Academic Search

Wireless sensor networks are comprised of a vast number of ultra-small fully autonomous computing, communi- cation and sensing devices, with very restricted energy and computing capabilities, that co-operate to accomplish a large sensing task. Such networks can be very useful in practice i.e. in the local detection of remote crucial events and the propagation of data reporting their realization to

Azzedine Boukerche; Ioannis Chatzigiannakis; Sotiris E. Nikoletseas

2005-01-01

355

Low Power Shoe Integrated Intelligent Wireless Gait Measurement System  

NASA Astrophysics Data System (ADS)

Gait analysis measurement is a method to assess and identify gait events and the measurements of dynamic, motion and pressure parameters involving the lowest part of the body. This significant analysis is widely used in sports, rehabilitation as well as other health diagnostic towards improving the quality of life. This paper presents a new system empowered by Inertia Measurement Unit (IMU), ultrasonic sensors, piezoceramic sensors array, XBee wireless modules and Arduino processing unit. This research focuses on the design and development of a low power ultra-portable shoe integrated wireless intelligent gait measurement using MEMS and recent microelectronic devices for foot clearance, orientation, error correction, gait events and pressure measurement system. It is developed to be cheap, low power, wireless, real time and suitable for real life in-door and out-door environment.

Wahab, Y.; Mazalan, M.; Bakar, N. A.; Anuar, A. F.; Zainol, M. Z.; Hamzah, F.

2014-04-01

356

Debate: Wired versus Wireless.  

ERIC Educational Resources Information Center

Debates the issue of investing in wiring schools for desktop computer networks versus using laptops and wireless networks. Included are cost considerations and the value of technology for learning. Suggestions include using wireless networks for existing schools, hardwiring computers for new construction, and not using computers for elementary…

Meeks, Glenn; Nair, Prakash

2000-01-01

357

Securing wireless mesh networks  

Microsoft Academic Search

Using wireless mesh networks to offer Internet connectivity is becoming a popular choice for wireless Internet service providers as it allows fast, easy, and inexpensive network deployment. However, security in WMNs is still in its infancy as very little attention has been devoted thus far to this topic by the research community. In this article we describe the specifics of

Naouel Ben Salem; Jean-Pierre Hubaux

2006-01-01

358

Wireless Sensor Networks  

Microsoft Academic Search

Wireless sensor networks are gaining popularity and are star- ting to be used in actual projects and commercial scale. Wi- reless sensor networks face dierent challenges than regular distributed systems, which have to be reflected in system and middleware design. Dierent middleware approaches are presented, along with implementing systems. The versatility of wireless sensor networks is underlined with examples of

Florian Schaub

359

Feasibility of retroreflective transdermal optical wireless communication.  

PubMed

There is an increasing demand for transdermal high-data-rate communication for use with in-body devices, such as pacemakers, smart prostheses, neural signals processors at the brain interface, and cameras acting as artificial eyes as well as for collecting signals generated within the human body. Prominent requirements of these communication systems include (1) wireless modality, (2) noise immunity and (3) ultra-low-power consumption for the in-body device. Today, the common wireless methods for transdermal communication are based on communication at radio frequencies, electrical induction, or acoustic waves. In this paper, we will explore another alternative to these methods--optical wireless communication (OWC)--for which modulated light carries the information. The main advantages of OWC in transdermal communication, by comparison to the other methods, are the high data rates and immunity to external interference availed, which combine to make it a promising technology for next-generation systems. In this paper, we present a mathematical model and experimental results of measurements from direct link and retroreflection link configurations with Gallus gallus domesticus derma as the transdermal channel. The main conclusion from this work is that an OWC link is an attractive communication solution in medical applications. For a modulating retroreflective link to become a competitive solution in comparison with a direct link, low-energy-consumption modulating retroreflectors should be developed. PMID:22722303

Gil, Yotam; Rotter, Nadav; Arnon, Shlomi

2012-06-20

360

A wide-band 760-GHz planar integrated Schottky receiver  

NASA Technical Reports Server (NTRS)

A wideband planar integrated heterodyne receiver has been developed for use at submillimeter-wave to FIR frequencies. The receiver consists of a log-periodic antenna integrated with a planar 0.8-micron GaAs Schottky diode. The monolithic receiver is placed on a silicon lens and has a measured room temperature double side-band conversion loss and noise temperature of 14.9 +/- 1.0 dB and 8900 +/- 500 K, respectively, at 761 GHz. These results represent the best performance to date for room temperature integrated receivers at this frequency.

Gearhart, Steven S.; Hesler, Jeffrey; Bishop, William L.; Crowe, Thomas W.; Rebeiz, Gabriel M.

1993-01-01

361

Wide-band six-region phase mask coronagraph.  

PubMed

An achromatic six-region phase mask coronagraph, used for the detection of exoplanets, is proposed. The mask has six regions in angular direction and could work in wideband. Furthermore, a six-level phase mask, as an example of the six-region phase mask, is theoretically investigated. According to numerical simulations, this specific mask has a deep elimination of starlight, good performance of achromatism and small inner working angle. As a single phase mask, the ratio of the remaining starlight of the six-level phase mask to the total incident starlight is less than 0.001 when the wavelength is between 500 nm and 600 nm. PMID:24515197

Hou, Fanzhen; Cao, Qing; Zhu, Minning; Ma, Ourui

2014-01-27

362

Wideband mm-wave log-periodic antennas  

Microsoft Academic Search

Wideband mm-wave end-fire and planar log-periodic antennas compatible with a recently developed surface micromachined process known as PolyStratatrade are discussed in this paper. Two embodiments of each log-periodic type are developed. Specifically, an instantaneous 2-110 GHz and a dual-band 18-50 GHz and 75-110 GHz planar log-periodic antennas with integrated rectangular micro-coaxial feeds\\/impedance transformers and VSWR < 2.5:1 are designed. An

Joseph Mruk; Zhou Hongyu; Manseok Uhm; Yuya Saito; Dejan Filipovic

2009-01-01

363

Real-time wideband cylindrical holographic surveillance system  

DOEpatents

A wideband holographic cylindrical surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply Fast Fourier Transforms and obtain a three dimensional cylindrical image.

Sheen, David M. (Richland, WA); McMakin, Douglas L. (Richland, WA); Hall, Thomas E. (Kennewick, WA); Severtsen, Ronald H. (Richland, WA)

1999-01-01

364

Static pressure and temperature compensated wideband fiber laser hydrophone  

NASA Astrophysics Data System (ADS)

Sensitive optical hydrophone is a key component for the design of compact fully optical acoustic arrays and one major issue about this kind of sensors is their sensitivity to hydrostatic pressure and temperature. We present in this paper a compact hydrophone which is optimized for reduced temperature sensitivity and high static pressure capability. High acoustic sensitivity is obtained through wideband mechanical amplification design. Two mock-ups have been realized and the measurements show good agreements with finite-element model. We present acoustic measurements as well as measurements in environmental conditions (temperature and pressure) obtained with a low noise opto-electronic interrogation system.

Launay, F.-X.; Lardat, R.; Bouffaron, R.; Roux, G.; Doisy, M.; Bergogne, C.

2013-05-01

365

Using wireless technologies in healthcare  

Microsoft Academic Search

With an increasingly mobile society and the worldwide deployment of mobile and wireless networks, wireless infrastructure can support many current and emerging healthcare applications. However, before wireless infrastructure can be used in a wide scale, there are several challenges that must be overcome. These include how to best utilise the capabilities of diverse wireless technologies and how to effectively manage

Upkar Varshney

2006-01-01

366

Portable emergency telemedicine system over wireless broadband and 3G networks.  

PubMed

The telemedicine system aims at monitoring patients remotely without limit in time and space. However the existing telemedicine systems exchange medical information simply in a specified location. Due to increasing speed in processing data and expanding bandwidth of wireless networks, it is possible to perform telemedicine services on personal digital assistants (PDA). In this paper, a telemedicine system on PDA was developed using wideband mobile networks such as Wi-Fi, HSDPA, and WiBro for high speed bandwidths. This system enables to utilize and exchange variety and reliable patient information of video, biosignals, chatting messages, and triage data. By measuring bandwidths of individual data of the system over wireless networks, and evaluating the performance of this system using PDA, we demonstrated the feasibility of the designed portable emergency telemedicine system. PMID:19964507

Hong, SungHye; Kim, SangYong; Kim, JungChae; Lim, DongKyu; Jung, SeokMyung; Kim, DongKeun; Yoo, Sun K

2009-01-01

367

Multiport Sensor RFIDs for Wireless Passive Sensing of Objects—Basic Theory and Early Results  

Microsoft Academic Search

A new family of passive sensor radio-frequency identification devices is here proposed for applications in the context of wireless sensor networks. The new tags, working in the ultra-high frequency band, are able to detect the value or the change of some features of the tagged body without using any specific sensor. Such tags are provided with multiple chips embedded either

Gaetano Marrocco; Lorenzo Mattioni; Claudio Calabrese

2008-01-01

368

Implementation of Multi-hop Routing Protocols for the Dramatic Range Enhancement of Wireless Sensor Networks  

E-print Network

with power consumption, namely sensing, communication, and data processing [3]. Secondly, although smaller of the WSNs is the transmission media. The nodes comprising an "ad-hoc" wireless sensor network antenna efficiency and power consumption, to the Ultra High Frequency (UHF) range, with the ISM

Tentzeris, Manos

369

Digital Front End for Wide-Band VLBI Science Receiver  

NASA Technical Reports Server (NTRS)

An upgrade to the very-long-baseline-interferometry (VLBI) science receiver (VSR) a radio receiver used in NASA's Deep Space Network (DSN) is currently being implemented. The current VSR samples standard DSN intermediate- frequency (IF) signals at 256 MHz and after digital down-conversion records data from up to four 16-MHz baseband channels. Currently, IF signals are limited to the 265-to-375-MHz range, and recording rates are limited to less than 80 Mbps. The new digital front end, denoted the Wideband VSR, provides improvements to enable the receiver to process wider bandwidth signals and accommodate more data channels for recording. The Wideband VSR utilizes state-of-the-art commercial analog-to-digital converter and field-programmable gate array (FPGA) integrated circuits, and fiber-optic connections in a custom architecture. It accepts IF signals from 100 to 600 MHz, sampling the signal at 1.28 GHz. The sample data are sent to a digital processing module, using a fiber-optic link for isolation. The digital processing module includes boards designed around an Advanced Telecom Computing Architecture (ATCA) industry-standard backplane. Digital signal processing implemented in FPGAs down-convert the data signals in up to 16 baseband channels with programmable bandwidths from 1 kHz to 16 MHz. Baseband samples are transmitted to a computer via multiple Ethernet connections allowing recording to disk at rates of up to 1 Gbps.

Jongeling, Andre; Sigman, Elliott; Navarro, Robert; Goodhart, Charles; Rogstad, Steve; Chandra, Kumar; Finley, Sue; Trinh, Joseph; Soriano, Melissa; White, Les; Proctor, Robert; Rayhrer, Benno

2006-01-01

370

Wideband Fractal Antennas for Holographic Imaging and Rectenna Applications  

SciTech Connect

At Pacific Northwest National Laboratory, wideband antenna arrays have been successfully used to reconstruct three-dimensional images at microwave and millimeter-wave frequencies. Applications of this technology have included portal monitoring, through-wall imaging, and weapons detection. Fractal antennas have been shown to have wideband characteristics due to their self-similar nature (that is, their geometry is replicated at different scales). They further have advantages in providing good characteristics in a compact configuration. We discuss the application of fractal antennas for holographic imaging. Simulation results will be presented. Rectennas are a specific class of antennas in which a received signal drives a nonlinear junction and is retransmitted at either a harmonic frequency or a demodulated frequency. Applications include tagging and tracking objects with a uniquely-responding antenna. It is of interest to consider fractal rectenna because the self-similarity of fractal antennas tends to make them have similar resonance behavior at multiples of the primary resonance. Thus, fractal antennas can be suited for applications in which a signal is reradiated at a harmonic frequency. Simulations will be discussed with this application in mind.

Bunch, Kyle J.; McMakin, Douglas L.; Sheen, David M.

2008-04-18

371

Wireless nanosensor network system  

NASA Astrophysics Data System (ADS)

Many types of wireless modules are being developed to enhance wireless performance with low power consumption, compact size, high data rates, and wide range coverage. However trade-offs must be taken into consideration in order to satisfy all aspects of wireless performance. For example, in order to increase the data rate and wide range coverage, power consumption should be sacrificed. To overcome these drawbacks, the paper presents a wireless client module which offers low power consumption along with a wireless receiver module that has the strength to provide high data rates and wide range coverage. Adopting Zigbee protocol in the wireless client module, the power consumption performance is enhanced so that it plays a part of the mobile device. On the other hand, the wireless receiver module, as adopting Zigbee and Wi-Fi protocol, provides high data rate, wide range coverage, and easy connection to the existing Internet network so that it plays a part of the portable device. This module demonstrates monitoring of gait analysis. The results show that the sensing data being measured can be monitored in any remote place with access to the Internet network.

Oh, Sechang; Kwon, Hyukjun; Kegley, Lauren; Yoon, Hargsoon; Varadan, Vijay K.

2009-03-01

372

``Low Power Wireless Technologies: An Approach to Medical Applications''  

NASA Astrophysics Data System (ADS)

Wireless communication supposed a great both -quantitative and qualitative, jump in the management of the information, allowing the access and interchange of it without the need of a physical cable connection. The wireless transmission of voice and information has remained in constant evolution, arising new standards like BluetoothTM, WibreeTM or ZigbeeTM developed under the IEEE 802.15 norm. These newest wireless technologies are oriented to systems of communication of short-medium distance and optimized for a low cost and minor consume, becoming recognized as a flexible and reliable medium for data communications across a broad range of applications due to the potential that the wireless networks presents to operate in demanding environments providing clear advantages in cost, size, power, flexibility, and distributed intelligence. About the medical applications, the remote health or telecare (also called eHealth) is getting a bigger place into the manufacturers and medical companies, in order to incorporate products for assisted living and remote monitoring of health parameteres. At this point, the IEEE 1073, Personal Health Devices Working Group, stablish the framework for these kind of applications. Particularly, the 1073.3.X describes the physical and transport layers, where the new ultra low power short range wireless technologies can play a big role, providing solutions that allow the design of products which are particularly appropriate for monitor people’s health with interoperability requirements.

Bellido O., Francisco J.; González R., Miguel; Moreno M., Antonio; de La Cruz F, José Luis

373

Digital wireless control system  

NASA Astrophysics Data System (ADS)

The Digital Wireless Control System (DWCS) is designed to initiate high explosives safely while using a wireless remote control system. Numerous safety features have been designed into the fire control system to mitigate the hazards associated with remote initiation of high explosives. These safety features range from a telemetry (TM) fire control status system to mechanical timers and keyed power lockout switches. The environment, safety, and health (ES&H) Standard Operating Procedure (SOP) SP471970 is intended as a guide when working with the DWCS. This report describes the Digital Wireless Control System and outlines each component's theory of operation and its relationship to the system.

Smith, R.

1993-08-01

374

Network coded wireless architecture  

E-print Network

Wireless mesh networks promise cheap Internet access, easy deployment, and extended range. In their current form, however, these networks suffer from both limited throughput and low reliability; hence they cannot meet the ...

Katti, Sachin Rajsekhar

2008-01-01

375

Wideband monolithically integrated front-end subsystems and components  

NASA Astrophysics Data System (ADS)

This thesis presents the analysis, design, and measurements of passive, monolithically integrated, wideband recta-coax and printed circuit board front-end components. Monolithic fabrication of antennas, impedance transformers, filters, and transitions lowers manufacturing costs by reducing assembly time and enhances performance by removing connectors and cabling between the devices. Computational design, fabrication, and measurements are used to demonstrate the capabilities of these front-end assemblies. Two-arm wideband planar log-periodic antennas fed using a horizontal feed that allows for filters and impedance transformers to be readily fabricated within the radiating region of the antenna are demonstrated. At microwave frequencies, low-cost printed circuit board processes are typically used to produce planar devices. A 1.8 to 11 GHz two-arm planar log-periodic antenna is designed with a monolithically integrated impedance transformer. Band rejection methods based on modifying the antenna aperture, use of an integrated filter, and the application of both methods are investigated with realized gain suppressions of over 25 dB achieved. The ability of standard circuit board technology to fabricate millimeter-wave devices up to 110 GHz is severely limited. Thin dielectrics are required to prevent the excitation of higher order modes in the microstrip substrate. Fabricating the thin line widths required for the antenna aperture also becomes prohibitively challenging. Surface micro-machining typically used in the fabrication of MEMS devices is capable of producing the extremely small features that can be used to fabricate antennas extending through W-band. A directly RF fed 18 to 110 GHz planar log-periodic antenna is developed. The antenna is fabricated with an integrated impedance transformer and additional transitions for measurement characterization. Singly terminated low-loss wideband millimeter-wave filters operating over V- and W- band are developed. High quality performance of an 18 to 100 GHz front-end is realized by dividing the single instantaneous antenna into two apertures operating from 18 to 50 and 50 to 100 GHz. Each channel features an impedance transformer, low-pass (low-frequency) or band-pass (high-frequency) filter, and grounded CPW launch. This dual-aperture front-end demonstrates that micromachining technology is now capable of fabricating broadband millimeter-wave components with a high degree of integration.

Mruk, Joseph Rene

376

Wide-Band Microwave Receivers Using Photonic Processing  

NASA Technical Reports Server (NTRS)

In wide-band microwave receivers of a type now undergoing development, the incoming microwave signals are electronically preamplified, then frequency-up-converted to optical signals that are processed photonically before being detected. This approach differs from the traditional approach, in which incoming microwave signals are processed by purely electronic means. As used here, wide-band microwave receivers refers especially to receivers capable of reception at any frequency throughout the range from about 90 to about 300 GHz. The advantage expected to be gained by following the up-conversion-and-photonic-processing approach is the ability to overcome the limitations of currently available detectors and tunable local oscillators in the frequency range of interest. In a receiver following this approach (see figure), a preamplified incoming microwave signal is up-converted by the method described in the preceeding article. The frequency up-converter exploits the nonlinearity of the electromagnetic response of a whispering gallery mode (WGM) resonator made of LiNbO3. Up-conversion takes place by three-wave mixing in the resonator. The WGM resonator is designed and fabricated to function simultaneously as an electro-optical modulator and to exhibit resonance at the microwave and optical operating frequencies plus phase matching among the microwave and optical signals circulating in the resonator. The up-conversion is an efficient process, and the efficiency is enhanced by the combination of microwave and optical resonances. The up-converted signal is processed photonically by use of a tunable optical filter or local oscillator, and is then detected. Tunable optical filters can be made to be frequency agile and to exhibit high resonance quality factors (high Q values), thereby making it possible to utilize a variety of signal-processing modalities. Therefore, it is anticipated that when fully developed, receivers of this type will be compact and will be capable of both wide-band and narrowband signal processing. Thus, one compact receiver of this type would afford the functionality that, heretofore, could have been obtained only by use of multiple heterodyne microwave receivers.

Matsko, Andrey; Maleki, Lute; Itchenko, Vladimir; Yu, Nan; Strekalov, Dmitry; Savchenkov, Anatoliy

2008-01-01

377

Convergence of Expert Opinion via the Wideband Delphi Method: An Application in Cost Estimation Models  

E-print Network

This paper discusses the notion of collective intelligence through the application of the Wideband Delphi method as a way to obtain convergence among a group of experts. The specific application is the definition and ...

Valerdi, Ricardo

2011-06-20

378

Chromatism compensation in wide-band nulling interferometry for exoplanet detection  

E-print Network

Chromatism compensation in wide-band nulling interferometry for exoplanet detection Julien Spronck decade, much effort has been dedi- cated to the search for exoplanets. The first exoplanet was discovered

379

47 CFR 36.155 - Wideband and exchange trunk (C&WF)-Category 2-apportionment procedures.  

Code of Federal Regulations, 2012 CFR

...PROPERTY COSTS, REVENUES, EXPENSES, TAXES AND RESERVES FOR TELECOMMUNICATIONS COMPANIES 1 Telecommunications Property Cable and Wire Facilities § 36.155 Wideband and exchange trunk (C&WF)—Category 2—apportionment procedures....

2012-10-01

380

47 CFR 36.155 - Wideband and exchange trunk (C&WF)-Category 2-apportionment procedures.  

Code of Federal Regulations, 2010 CFR

...PROPERTY COSTS, REVENUES, EXPENSES, TAXES AND RESERVES FOR TELECOMMUNICATIONS COMPANIES 1 Telecommunications Property Cable and Wire Facilities § 36.155 Wideband and exchange trunk (C&WF)—Category 2—apportionment procedures....

2010-10-01

381

47 CFR 36.155 - Wideband and exchange trunk (C&WF)-Category 2-apportionment procedures.  

Code of Federal Regulations, 2013 CFR

...PROPERTY COSTS, REVENUES, EXPENSES, TAXES AND RESERVES FOR TELECOMMUNICATIONS COMPANIES 1 Telecommunications Property Cable and Wire Facilities § 36.155 Wideband and exchange trunk (C&WF)—Category 2—apportionment procedures....

2013-10-01

382

47 CFR 36.155 - Wideband and exchange trunk (C&WF)-Category 2-apportionment procedures.  

Code of Federal Regulations, 2011 CFR

...PROPERTY COSTS, REVENUES, EXPENSES, TAXES AND RESERVES FOR TELECOMMUNICATIONS COMPANIES 1 Telecommunications Property Cable and Wire Facilities § 36.155 Wideband and exchange trunk (C&WF)—Category 2—apportionment procedures....

2011-10-01

383

A GPU-Based Wide-Band Radio Spectrometer  

E-print Network

The Graphics Processing Unit (GPU) has become an integral part of astronomical instrumentation, enabling high-performance online data reduction and accelerated online signal processing. In this paper, we describe a wide-band reconfigurable spectrometer built using an off-the-shelf GPU card. This spectrometer, when configured as a polyphase filter bank (PFB), supports a dual-polarization bandwidth of up to 1.1 GHz (or a single-polarization bandwidth of up to 2.2 GHz) on the latest generation of GPUs. On the other hand, when configured as a direct FFT, the spectrometer supports a dual-polarization bandwidth of up to 1.4 GHz (or a single-polarization bandwidth of up to 2.8 GHz).

Chennamangalam, Jayanth; Jones, Glenn; Chen, Hong; Ford, John; Kepley, Amanda; Lorimer, D R; Nie, Jun; Prestage, Richard; Roshi, D Anish; Wagner, Mark; Werthimer, Dan

2014-01-01

384

Development of a wideband wattmeter as a laboratory instrument  

NASA Technical Reports Server (NTRS)

A portable, solid state, wideband wattmeter has been developed as a general purpose type of laboratory instrument. Its circuit and component investigations and evaluation data are presented. A prototype unit was used extensively, and served as the basis for a second instrument incorporating refined circuitry and improved packaging. The wattmeter provides true four quadrant operation which permits instantaneous indication of real power as an oscilloscope display. Major performance factors are: frequency bandwidth DC to 1 MHz plus or minus 1 db; current range 10 mA to 100 amperes peak; voltage range 1 volt to 1000 volts peak; accuracy plus or minus 2% of full scale reading. Oscilloscope data for typical switching transients in a transistor inverter circuit are included.

Landes, L. G.; Liu, Y. Y.

1971-01-01

385

Novel planar wideband omni-directional quasi log-periodic antenna  

Microsoft Academic Search

In this paper, a novel and simple wideband planar omni-directional antenna is proposed. The simultaneously wideband and omni-directional characteristics of the proposed structure are achieved by adding two mutually-coupled elements to the conventional dipole antenna. This newly proposed structure is able to extend the bandwidth (VSWR? 2:1, at UHF band) to 30% compared to simple dipole antennas while maintaining an

Heng-Tung Hsu; James C. Rautio; San-Wen Chang

2005-01-01

386

A Wide-Band Metamaterial Absorber Based on Loaded Magnetic Resonators  

Microsoft Academic Search

A wide-band polarization-insensitive and wide-angle metamaterial absorber based on loaded magnetic resonators is presented. The unit cell of this absorber consists of a magnetic resonator loaded with lumped resistances, a dielectric substrate and a back metal film. Theoretical and simulated results show that this absorber has a wideband strong absorption for the incident wave from 3.87 GHz to 21.09 GHz.

Chao Gu; Shao-Bo Qu; Zhi-Bin Pei; Hua Ma; Zhuo Xu; Peng Bai; Wei-Dong Peng; Bao-Qin Lin

2011-01-01

387

Low-light imaging method with visible-band and wide-band image pair  

Microsoft Academic Search

Images captured from digital camera suffer noise due to high sensor gain under dark conditions. Furthermore, camera-shake is unavoidable when exposure time is long enough to have desirable SNR. This paper presents an image capturing method that enhances image quality in low-light environments by fusing visible-band (400 ~ 700 nm) image and wide-band (400 ~ 1000 nm) image. Wide-band image

Youngjin Yoo; Wonhee Choe; Jaehyun Kwon; Seong-Deok Lee; Chang-Yeong Kim

2009-01-01

388

Low power, high linearity wideband receiver front-end for LTE application  

Microsoft Academic Search

This paper presents a low power wideband receiver front-end implemented in 0.18 um CMOS technology for LTE application. The front-end includes a low-noise amplifier and a quadrature passive current commutating mixer. The inductive peaking LNA is designed using common gate topology for wideband matching with low power consumption. A noise cancellation technique is adopted for the LNA to achieve NF

Hoai-Nam Nguyen; Viet-Hoang Le; Ki-Uk Gwak; Jeong-Yeol Bae; Seok-Kyun Han; Sang-Gug Lee

2011-01-01

389

Rapid Sensing of Underutilized, Wideband Spectrum Using the Random Demodulator  

E-print Network

, Waheed U. Bajwa2, Robert Calderbank3 Department of Electrical Engineering, Princeton University@princeton.edu 2 waheed.bajwa@rutgers.edu 3 robert.calderbank@duke.edu Abstract--Efficient spectrum sensing efficiently use wireless spectrum. The so-called white-space devices are an exam- ple that utilize unused

Bajwa, Waheed U.

390

Video transmission over wireless networks  

E-print Network

Compressed video bitstream transmissions over wireless networks are addressed in this work. We first consider error control and power allocation for transmitting wireless video over CDMA networks in conjunction with multiuser detection. We map a...

Zhao, Shengjie

2005-08-29

391

Integer-linear-programing optimization in scalable video multicast with adaptive modulation and coding in wireless networks.  

PubMed

The advancement in wideband wireless network supports real time services such as IPTV and live video streaming. However, because of the sharing nature of the wireless medium, efficient resource allocation has been studied to achieve a high level of acceptability and proliferation of wireless multimedia. Scalable video coding (SVC) with adaptive modulation and coding (AMC) provides an excellent solution for wireless video streaming. By assigning different modulation and coding schemes (MCSs) to video layers, SVC can provide good video quality to users in good channel conditions and also basic video quality to users in bad channel conditions. For optimal resource allocation, a key issue in applying SVC in the wireless multicast service is how to assign MCSs and the time resources to each SVC layer in the heterogeneous channel condition. We formulate this problem with integer linear programming (ILP) and provide numerical results to show the performance under 802.16?m environment. The result shows that our methodology enhances the overall system throughput compared to an existing algorithm. PMID:25276862

Lee, Dongyul; Lee, Chaewoo

2014-01-01

392

Integer-Linear-Programing Optimization in Scalable Video Multicast with Adaptive Modulation and Coding in Wireless Networks  

PubMed Central

The advancement in wideband wireless network supports real time services such as IPTV and live video streaming. However, because of the sharing nature of the wireless medium, efficient resource allocation has been studied to achieve a high level of acceptability and proliferation of wireless multimedia. Scalable video coding (SVC) with adaptive modulation and coding (AMC) provides an excellent solution for wireless video streaming. By assigning different modulation and coding schemes (MCSs) to video layers, SVC can provide good video quality to users in good channel conditions and also basic video quality to users in bad channel conditions. For optimal resource allocation, a key issue in applying SVC in the wireless multicast service is how to assign MCSs and the time resources to each SVC layer in the heterogeneous channel condition. We formulate this problem with integer linear programming (ILP) and provide numerical results to show the performance under 802.16?m environment. The result shows that our methodology enhances the overall system throughput compared to an existing algorithm.

Lee, Chaewoo

2014-01-01

393

Free space link budget evaluation of UWB-IR systems  

Microsoft Academic Search

Ultra wideband impulse radio (UWB-IR) technology is an ideal candidate for wireless networks that can be utilized for short-range, high-speed, low power, and low cost indoor applications. The link budget of the free space propagation loss is usually estimated by using Friis' transmission formula. However, it is not directly applicable to ultra wideband impulse radio transmission systems, in particular the

Sathaporn Promwong; Wataru Hachitani; Jun-ichi Takada

2004-01-01

394

Barrier coverage with wireless sensors  

Microsoft Academic Search

In old times, castles were surrounded by moats (deep trenches filled with water, and even alligators) to thwart or discourage intrusion attempts. One can now replace such barriers with stealthy and wireless sensors. In this paper, we develop theoretical foundations for laying barriers of wireless sensors. We define the notion of k-barrier coverage of a belt region using wireless sensors.

Santosh Kumar; Ten-Hwang Lai; Anish Arora

2005-01-01

395

Energy options for wireless sensors  

Microsoft Academic Search

Successful design strategies for energy efficient wireless sensor networks must involve the optimization of system energy at all levels including sensor circuits, communication, and powering methods. The paper reviews the various sensor powering options focusing on remote wireless powering and hybrid powering solutions. The comparative analysis of the two main wireless remote powering methods based on power transfer from RF

C. Belhadj-Yahya; Prince Mohammad Bin

2010-01-01

396

Wireless Acoustic Measurement System  

NASA Technical Reports Server (NTRS)

A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in "Predicting Rocket or Jet Noise in Real Time" (SSC-00215-1), which appears elsewhere in this issue of NASA Tech Briefs. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro-ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that provides an intuitive graphical user interface through which an operator at the control server can control the operations of the field stations for calibration and for recording of measurement data. A test engineer positions and activates the WAMS. The WAMS automatically establishes the wireless network. Next, the engineer performs pretest calibrations. Then the engineer executes the test and measurement procedures. After the test, the raw measurement files are copied and transferred, through the wireless network, to a hard disk in the control server. Subsequently, the data are processed into 1/3-octave spectrograms.

Anderson, Paul D.; Dorland, Wade D.

2005-01-01

397

Wireless Acoustic Measurement System  

NASA Technical Reports Server (NTRS)

A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/ Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in the article on page 8. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro- ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that provides an intuitive graphical user interface through which an operator at the control server can control the operations of the field stations for calibration and for recording of measurement data. A test engineer positions and activates the WAMS. The WAMS automatically establishes the wireless network. Next, the engineer performs pretest calibrations. Then the engineer executes the test and measurement procedures. After the test, the raw measurement files are copied and transferred, through the wireless network, to a hard disk in the control server. Subsequently, the data are processed into 1.3-octave spectrograms.

Anderson, Paul D.; Dorland, Wade D.; Jolly, Ronald L.

2007-01-01

398

Wireless optical network for a home network  

NASA Astrophysics Data System (ADS)

During the European collaborative project OMEGA, two optical-wireless prototypes have been developed. The first prototype operates in the near-infrared spectral region and features Giga Ethernet connectivity, a simple transceiver architecture due to the use of on-off keying, a multi-sector transceiver, and an ultra-fast switch for sector-to-sector hand over. This full-duplex system, composed by one base station and one module, transmits data on three meters. The second prototype is a visible-light-communications system based on DMT signal processing and an adapted MAC sublayer. Data rates around to 100 Mb/s at the physical layer are achieved. This broadcast system, composed also by one base station and one module, transmits data up to two meters. In this paper we present the adapted optical wireless media-access-control sublayer protocol for visible-light communications. This protocol accommodates link adaptation from 128 Mb/s to 1024 Mb/s with multi-sector coverage, and half-duplex or full-duplex transmission.

Bouchet, Olivier; Porcon, Pascal; Walewski, Joachim W.; Nerreter, Stefan; Langer, Klaus-Dieter; Fernández, Luz; Vucic, Jelena; Kamalakis, Thomas; Ntogari, Georgia; Neokosmidis, Ioannis; Gueutier, Eric

2010-08-01

399

Terabit Wireless Communication Challenges  

NASA Technical Reports Server (NTRS)

This presentation briefly discusses a research effort on Terabit Wireless communication systems for possible space applications. Recently, terahertz (THz) technology (300-3000 GHz frequency) has attracted a great deal of interest from academia and industry. This is due to a number of interesting features of THz waves, including the nearly unlimited bandwidths available, and the non-ionizing radiation nature which does not damage human tissues and DNA with minimum health threat. Also, as millimeter-wave communication systems mature, the focus of research is, naturally, moving to the THz range. Many scientists regard THz as the last great frontier of the electromagnetic spectrum, but finding new applications outside the traditional niches of radio astronomy, Earth and planetary remote sensing, and molecular spectroscopy particularly in biomedical imaging and wireless communications has been relatively slow. Radiologists find this area of study so attractive because t-rays are non-ionizing, which suggests no harm is done to tissue or DNA. They also offer the possibility of performing spectroscopic measurements over a very wide frequency range, and can even capture signatures from liquids and solids. According to Shannon theory, the broad bandwidth of the THz frequency bands can be used for terabit-per-second (Tb/s) wireless communication systems. This enables several new applications, such as cell phones with 360 degrees autostereoscopic displays, optic-fiber replacement, and wireless Tb/s file transferring. Although THz technology could satisfy the demand for an extremely high data rate, a number of technical challenges need to be overcome before its development. This presentation provides an overview the state-of-the- art in THz wireless communication and the technical challenges for an emerging application in Terabit wireless systems. The main issue for THz wave propagation is the high atmospheric attenuation, which is dominated by water vapor absorption in the THz frequency band. The technical challenges in design such a system and the techniques to overcome the challenges will be discussed in this presentation.

Hwu, Shian U.

2012-01-01

400

Project description On-chip noise coupling issues for high sensitivity, short range ultra-wide band com-  

E-print Network

propagate effectively to RF ar- eas where it may couple into for instance inductors and transistorsProject description On-chip noise coupling issues for high sensitivity, short range ultra-wide band of the main-stream wireless technologies for the next couple of decades [2]. Considering the amount

Hansen, René Rydhof

401

Concept and Analysis of a Satellite for Space-Based Radio Detection of Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

We present a concept for on-orbit radio detection of ultra-high energy cosmic rays (UHECRs) that has the potential to provide collection rates of ~100 events per year for energies above 10^20 eV. The synoptic wideband orbiting radio detector (SWORD) mission's high event statistics at these energies combined with the pointing capabilities of a space-borne antenna array could enable charged particle astronomy. The detector concept is based on ANITA's successful detection UHECRs where the geosynchrotron radio signal produced by the extended air shower is reflected off the Earth's surface and detected in flight.

Romero-Wolf, Andrew; Gorham, P.; Booth, J.; Chen, P.; Duren, R. M.; Liewer, K.; Nam, J.; Saltzberg, D.; Schoorlemmer, H.; Wissel, S.; Zairfian, P.

2014-01-01

402

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project.

Fred Sabins

2001-01-15

403

Insecurity of Wireless Networks  

SciTech Connect

Wireless is a powerful core technology enabling our global digital infrastructure. Wi-Fi networks are susceptible to attacks on Wired Equivalency Privacy, Wi-Fi Protected Access (WPA), and WPA2. These attack signatures can be profiled into a system that defends against such attacks on the basis of their inherent characteristics. Wi-Fi is the standard protocol for wireless networks used extensively in US critical infrastructures. Since the Wired Equivalency Privacy (WEP) security protocol was broken, the Wi-Fi Protected Access (WPA) protocol has been considered the secure alternative compatible with hardware developed for WEP. However, in November 2008, researchers developed an attack on WPA, allowing forgery of Address Resolution Protocol (ARP) packets. Subsequent enhancements have enabled ARP poisoning, cryptosystem denial of service, and man-in-the-middle attacks. Open source systems and methods (OSSM) have long been used to secure networks against such attacks. This article reviews OSSMs and the results of experimental attacks on WPA. These experiments re-created current attacks in a laboratory setting, recording both wired and wireless traffic. The article discusses methods of intrusion detection and prevention in the context of cyber physical protection of critical Internet infrastructure. The basis for this research is a specialized (and undoubtedly incomplete) taxonomy of Wi-Fi attacks and their adaptations to existing countermeasures and protocol revisions. Ultimately, this article aims to provide a clearer picture of how and why wireless protection protocols and encryption must achieve a more scientific basis for detecting and preventing such attacks.

Sheldon, Frederick T [ORNL; Weber, John Mark [Dynetics, Inc.; Yoo, Seong-Moo [University of Alabama, Huntsville; Pan, W. David [University of Alabama, Huntsville

2012-01-01

404

uncorrectedproof Wireless Pers Commun  

E-print Network

Protocols in Wireless Networks: Performance Analysis and Optimum Power Allocation Weifeng Su � Ahmed K communications.18 The optimum power allocation depends on the channel link quality. An interesting result19: 36 AuthorProof #12;uncorrectedproof W. Su et al. depend on the direct link between source

Liu, K. J. Ray

405

Inkjet-printed paper\\/polymer-based “green” RFID and Wireless Sensor Nodes: The final step to bridge cognitive intelligence, nanotechnology and RF?  

Microsoft Academic Search

In this talk, inkjet-printed flexible antennas, RF electronics and sensors fabricated on paper and other polymer (e.g.LCP) substrates are introduced as a system-level solution for ultra-low-cost mass production of UHF Radio Frequency Identification (RFID) Tags and Wireless Sensor Nodes (WSN) in an approach that could be easily extended to other microwave and wireless applications. The talk will cover examples from

M. M. Tentzeris

2010-01-01

406

Predicting the intelligibility of vocoded and wideband Mandarin Chinese  

PubMed Central

Due to the limited number of cochlear implantees speaking Mandarin Chinese, it is extremely difficult to evaluate new speech coding algorithms designed for tonal languages. Access to an intelligibility index that could reliably predict the intelligibility of vocoded (and non-vocoded) Mandarin Chinese is a viable solution to address this challenge. The speech-transmission index (STI) and coherence-based intelligibility measures, among others, have been examined extensively for predicting the intelligibility of English speech but have not been evaluated for vocoded or wideband (non-vocoded) Mandarin speech despite the perceptual differences between the two languages. The results indicated that the coherence-based measures seem to be influenced by the characteristics of the spoken language. The highest correlation (r= 0.91–0.97) was obtained in Mandarin Chinese with a weighted coherence measure that included primarily information from high-intensity voiced segments (e.g., vowels) containing F0 information, known to be important for lexical tone recognition. In contrast, in English, highest correlation was obtained with a coherence measure that included information from weak consonants and vowel?consonant transitions. A band-importance function was proposed that captured information about the amplitude envelope contour. A higher modulation rate (100 Hz) was found necessary for the STI-based measures for maximum correlation (r?=?0.94–0.96) with vocoded Mandarin and English recognition. PMID:21568429

Chen, Fei; Loizou, Philipos C.

2011-01-01

407

Cluster Wideband Data Products in the Cluster Active Archive  

NASA Astrophysics Data System (ADS)

Cluster Wideband Data (WBD) plasma wave receivers are mounted on all four of the Cluster spacecraft providing approximately 4-7% orbit coverage since mission operations began in February 2001. Data obtained by the WBD instruments are downlinked in real time to various Deep Space Network (DSN) and Panska Ves (PV) ground stations. The strengths of the WBD instruments lie in their high time and frequency resolution data, which allow analysis of the wave fine structure in order to more accurately investigate the linear and nonlinear nature of the waves, and in their use in carrying out Very Long Baseline Interferometry (VLBI) investigations to locate and characterize remote wave sources and their characteristics. The WBD team has already archived at the Cluster Active Archive (CAA) the documentation, software and data plots required for carrying on an independent scientific investigation. A document on interpretation issues has also been archived to help ensure that signals which are not naturally in the plasma are not misinterpreted. The WBD team also plans to archive digital, calibrated data files for the entire mission in cdf format at NASA's CDAWeb and submit these files for conversion to the Cluster standard cef format and archiving at the CAA. In order to ensure that the calibration of the WBD data has been done properly, WBD has taken part in Cluster cross calibration activities with the other wave instruments with regard to wave amplitudes in the time and frequency domains and with the PEACE instruments with regard to low density measurements.

Pickett, J. S.; Seeberger, J. M.; Christopher, I. W.; Santolík, O.; Sigsbee, K. M.

408

[High-precision wavelength calibration of wide-band monochromator].  

PubMed

Usually the monochromator is used to output monochromatic light to calibrate the space remote sensing spectrometer. In the present paper, the confidence of space remote sensing spectrometer is used as a standard to evaluate the precision of wide-band monochromator wavelength calibration. Through analysis of the accuracy of the instrument, the monochromator wavelength repeatability error and deviations was obtained respectively. And the intrinsic spectrum of the high pressure mercury lamp and the grating diffraction was used as calibration lines to avoid the error caused by replacing the light source. Through the special method of wavelength calibration to shorten the scan time, the Gaussian fitting was used to look for peaks of wavelength to reduce error. Finally, the relationship derived from polynomial fitting to measure the exact wavelengths' accuracy of the monochromator and calculate the calibration confidence of the space remote sensing spectrometer. Using this method, we can make wavelength accuracy of the 1.5 M monochromator with wavelength band from 200 to 840 nm to reach to +/- 0.016 nm, then the confidence of the space remote sensing spectrometer can reach to 99.82%. PMID:23285905

Zhang, Zi-Hui; Wang, Shu-Rong; Huang, Yu; Li, Bo; Yu, Xiang-Yang; Lin, Guan-Yu

2012-10-01

409

Propagation phenomena of wideband guided waves in a bended pipe.  

PubMed

Ultrasonic guided waves in pipes have been anticipated as a rapid screening technique for pipe inspection because of their long-range propagation due to low energy leakage. In this paper, the propagation phenomena of guided waves in a bended pipe were investigated using a wideband laser ultrasonic system. The laser ultrasonic system, together with wavelet transformation, is a powerful tool for observing the dispersive phenomena intrinsic to guided waves. Bended stainless steel (SUS304) pipes with 6-mm outer diameter and 1-mm wall thickness were used in the experiments. The bending angles of the pipes were set to 0 degrees (straight pipe), 10 degrees, 30 degrees, 60 degrees and 90 degrees. The radius of the bend was 12.5 mm in all the pipes. A Q-switched Nd:YAG laser was employed to generate the guided waves. The generated guided waves were detected with a heterodyne interferometer. The obtained time-domain signals and their wavelet coefficients indicated the following two conclusions: (1) The amplitude of the F(1,1) mode converted from the L(0,1) mode increased with the increase of the bending angle. (2) Mode conversions from the L(0,1) to F(1,1) modes and vice versa were clearly observed in the low-frequency range up to around 200 kHz. PMID:16806367

Nishino, Hideo; Yoshida, Kenichi; Cho, Hideo; Takemoto, Mikio

2006-12-22

410

Collaborative Wideband Compressed Signal Detection in Interplanetary Internet  

NASA Astrophysics Data System (ADS)

As the development of autonomous radio in deep space network, it is possible to actualize communication between explorers, aircrafts, rovers and satellites, e.g. from different countries, adopting different signal modes. The first mission to enforce the autonomous radio is to detect signals of the explorer autonomously without disturbing the original communication. This paper develops a collaborative wideband compressed signal detection approach for InterPlaNetary (IPN) Internet where there exist sparse active signals in the deep space environment. Compressed sensing (CS) can be utilized by exploiting the sparsity of IPN Internet communication signal, whose useful frequency support occupies only a small portion of an entirely wide spectrum. An estimate of the signal spectrum can be obtained by using reconstruction algorithms. Against deep space shadowing and channel fading, multiple satellites collaboratively sense and make a final decision according to certain fusion rule to gain spatial diversity. A couple of novel discrete cosine transform (DCT) and walsh-hadamard transform (WHT) based compressed spectrum detection methods are proposed which significantly improve the performance of spectrum recovery and signal detection. Finally, extensive simulation results are presented to show the effectiveness of our proposed collaborative scheme for signal detection in IPN Internet. Compared with the conventional discrete fourier transform (DFT) based method, our DCT and WHT based methods reduce computational complexity, decrease processing time, save energy and enhance probability of detection.

Wang, Yulin; Zhang, Gengxin; Bian, Dongming; Gou, Liang; Zhang, Wei

2014-07-01

411

47 CFR 90.1432 - Conditions for waiver to allow limited and temporary wideband operations in the 700 MHz public...  

Code of Federal Regulations, 2012 CFR

...renewal will be granted. (h) Grandfathered wideband STA operations. Upon request, the Public Safety and...operating a wideband system as of July 31, 2007 pursuant to STA to extend the STA grant for periods of no more than 180 days until,...

2012-10-01

412

Engineering the ULTra System  

NSDL National Science Digital Library

The Advanced Transport Group at the University of Bristol, upon considering current traffic congestion problems in England and throughout the world, attempted to "identify the ideal system for future urban transport." The group's work has led to the development of the Urban Light Transport (ULTra) System. This paper, published in September 2002, describes the engineering challenges and accomplishments of the endeavor. Thus far, a test track has been constructed, and an initial vehicle design was successfully demonstrated. The ULTra home page provides much more information, documents, and videos.

Lowson, Martin.

2002-01-01

413

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2002-07-30

414

A Novel Compact Wideband TSA Array for Near-Surface Ice Sheet Penetrating Radar Applications  

NASA Astrophysics Data System (ADS)

A novel compact tapered slot antenna (TSA) array for near-surface ice sheet penetrating radar applications is presented. This TSA array is composed of eight compact antenna elements which are etched on two 480mm × 283mm FR4 substrates. Each antenna element is fed by a wideband coplanar waveguide (CPW) to coupled strip-line (CPS) balun. The two antenna substrates are connected together with a metallic baffle. To obtain wideband properties, another two metallic baffles are used along broadsides of the array. This array is fed by a 1 × 8 wideband power divider. The measured S11 of the array is less than -10dB in the band of 500MHz-2GHz, and the measured gain is more than 6dBi in the whole band which agrees well with the simulated results.

Zhang, Feng; Liu, Xiaojun; Fang, Guangyou

2014-03-01

415

A Wide-Band Metamaterial Absorber Based on Loaded Magnetic Resonators  

NASA Astrophysics Data System (ADS)

A wide-band polarization-insensitive and wide-angle metamaterial absorber based on loaded magnetic resonators is presented. The unit cell of this absorber consists of a magnetic resonator loaded with lumped resistances, a dielectric substrate and a back metal film. Theoretical and simulated results show that this absorber has a wideband strong absorption for the incident wave from 3.87 GHz to 21.09 GHz. Simulated absorbance values under loading and unloading conditions indicate that electrocircuit's resonances are more stable than electromagnetic resonances and thus can be used to realize wide-band absorption. Simulated absorbance values under different polarization angles and different angles of incidence indicate that this absorber is polarization-insensitive and wide-angle. It may have potential applications in military fields.

Gu, Chao; Qu, Shao-Bo; Pei, Zhi-Bin; Ma, Hua; Xu, Zhuo; Bai, Peng; Peng, Wei-Dong; Lin, Bao-Qin

2011-06-01

416

Design and experimental verification of terahertz wideband filter based on double-layered metal hole arrays.  

PubMed

A terahertz wideband filter based on double layer metal hole arrays is designed in this paper. A metal hole array is perforated on a metal layer with a square array of circular air holes. The transmission characteristics of the electromagnetic waves through the metal hole array can be determined by the accumulation of in-phase scattering, spoof surface plasmon polaritons, and waveguide modes. The transmission spectrum is tuned by adding another identical layer metal hole array, and a wideband filter can be formed accordingly. Samples containing double-layered metal hole arrays were fabricated by micromachining technology. A wideband filter with center frequency located at 0.8 THz and FWHM reaching 400 GHz was experimentally achieved. PMID:22410895

Rao, Lei; Yang, Dongxiao; Zhang, Le; Li, Tao; Xia, Song

2012-03-01

417

Wideband antireflection coatings on germanium and filters for second optical window  

NASA Astrophysics Data System (ADS)

The investigation results of wideband (8-12 ?m) antireflection coatings on germanium substrate and spectral characteristics of interference wideband filter for spectral range of 8-12 ?m are presented. For design of filters and antireflection coatings the following layer materials were used: Ge, ZnS and Mira, and substrate materials such as: Ge for antireflection coatings and ZnSe for interference filters. Wideband filter for the range of 8-12 ?m requires application of additional two filters cutting off radiation from the range of 1-7 ?m. The cutting off filters are interference filters for which construction germanium, Mira, and ZnS were used. The constructions of basic and cutting off filters were designed considering technical possibilities of vacuum device BAK 550 of the Balzers firm.

Ciosek, Jerzy; Firak, Jozef; Stanislawek, Urszula; Kwasny, Miroslaw; Kopczynski, Krzysztof

2003-10-01

418

Efficient Security Mechanisms for mHealth Applications Using Wireless Body Sensor Networks  

PubMed Central

Recent technological advances in wireless communications and physiological sensing allow miniature, lightweight, ultra-low power, intelligent monitoring devices, which can be integrated into a Wireless Body Sensor Network (WBSN) for health monitoring. Physiological signals of humans such as heartbeats, temperature and pulse can be monitored from a distant location using tiny biomedical wireless sensors. Hence, it is highly essential to combine the ubiquitous computing with mobile health technology using wireless sensors and smart phones to monitor the well-being of chronic patients such as cardiac, Parkinson and epilepsy patients. Since physiological data of a patient are highly sensitive, maintaining its confidentiality is highly essential. Hence, security is a vital research issue in mobile health (mHealth) applications, especially if a patient has an embarrassing disease. In this paper a three tier security architecture for the mHealth application is proposed, in which light weight data confidentiality and authentication protocols are proposed to maintain the privacy of a patient. Moreover, considering the energy and hardware constraints of the wireless body sensors, low complexity data confidential and authentication schemes are designed. Performance evaluation of the proposed architecture shows that they can satisfy the energy and hardware limitations of the sensors and still can maintain the secure fabrics of the wireless body sensor networks. Besides, the proposed schemes can outperform in terms of energy consumption, memory usage and computation time over standard key establishment security scheme. PMID:23112734

Sahoo, Prasan Kumar

2012-01-01

419

Wireless Technologies for Healthcare Applications  

Microsoft Academic Search

Wireless and mobile technologies are widely accepted, influencing many aspects of our daily life (Agrawal and Zeng, 2003;\\u000a Bing 2000). Wireless systems are designed to provide “anytime, anywhere” service, enabling data entry and data access by medical\\u000a personnel at the point of care, direct data acquisition from medical devices, patient and device identification, and remote\\u000a patient management. Wireless technologies will

Brent Priddy; Emil Jovanov

420

Wireless LAN G001 Panasonic  

E-print Network

CPU System Memory HDD Display Size Weight OS Accessory LAN Wireless LAN G001 Panasonic Let's note CF- W2 Pentium M 1GHz 512MB RAM 20GB 12inch 1.3kg WinXP Pro - /Wireless G002 Panasonic Let's note CF- W4 Pentium M 1.2GHz 512MB 60GB 12inch 1.2kg WinXP Pro - /Wireless G003 Panasonic Let's note CF- Y

Katsumoto, Shingo

421

A real-time receive method of wideband radar based on subband pulse compression  

NASA Astrophysics Data System (ADS)

The data rate with high capacity and speed of wideband signal makes its real-time processing limited by hardware and software. In this paper, wideband signal is made pulse compression based on subband pulse compression system. It is used uniform complex modulation to generate analysis filter bank and synthesis filter bank, then signals are processed in each subband. The processed results of simulated and measured datas indicate, that the parallel means of subband pulse compression raises the operation speed and improves real-time processing performance of the system, selecting proper subband number according to the data quantity when the result closed to that of directed pulse compression.

Li, Ming; Fu, Wei; Zhang, Peng; Wu, Yan

2011-10-01

422

Voice and data communication experiments on a wideband satellite/terrestrial internetwork system  

NASA Astrophysics Data System (ADS)

A status report is presented on the testbed and experimental results pertaining to an experimental wideband satellite/terrestrial internetwork system used for the development and experimental evaluation of packet voice and data multiplexing and internetting techniques, as well as advanced satellite/terrestrial integration and routing techniques. Separate local systems have been developed, concentrating on packet voice/data multiplexing (DARPA) and on routing and satellite/terrestrial integration for the Defense Switched Network. Specific experiments in recent years have concentrated on multiuser internet packet speech and on interfacing digital circuit-switched facilities with the wideband packet satellite system.

Heggestad, H. M.; Weinstein, C. J.

423

Wide-Band Optical Filter Optimized for Deep Imaging of Small Solar System Bodies  

NASA Astrophysics Data System (ADS)

This paper describes a newly designed wide-band optical filter. It is optimized for deep imaging of small solar-system bodies. The new filter, which we denote as W i, is designed to reduce contamination by light pollution from street lamps, especially strong mercury and sodium emission lines. It is also useful for reducing unwanted scattered moonlight. Compared with the use of a commercially available long-wave cut wide-band filter, the signal-to-noise ratios in the detection of asteroids are improved by about 6% by using the W i filter.

Okumura, Shin-ichiro; Nishiyama, Kota; Urakawa, Seitaro; Sakamoto, Tsuyoshi; Takahashi, Noritsugu; Yoshikawa, Makoto

2012-06-01

424

Wireless drive of piezoelectric components.  

E-print Network

??To widen the application range of piezoelectric devices, various new techniques including wireless drive of piezoelectric components by parallel plate capacitor structure, focused electric field,… (more)

Satyanarayan Bhuyan.

2011-01-01

425

Characterization measurements of the wideband infrared scene projector resistor array  

NASA Astrophysics Data System (ADS)

Kinetic energy weapon (KEW) programs under the Ballistic Missile Defense Office (BMDO) need high fidelity, fast framing infrared (IR) imaging seekers. As imaging sensors have matured to support BMDO, the complexity of functions assigned to the KEW weapon systems has amplified the necessity for robust hardware-in-the-loop (HWIL) simulation facilities to reduce program risk. Tactical weapon systems are also turning to imaging focal plane array (FPA) seekers. They too require more sophisticated HWIL testing. The IR projector, an integral component of a HWIL simulation, must reproduce the real world with enough fidelity that the unit-under-tests's (UUT) software will respond to the projected scenario of images as though it were viewing the real world. The MOSFET resistor array IR scene projector shows great promise in cryogenic vacuum chamber as well as room temperature testing. Under the wideband infrared scene projector (WISP) program, an enhanced version of the resistor array is currently under development. When the WISP system is delivered, the projector will consist of a 512 by 512 baseline array with the center 128 by 128 resistors having a higher output capability. For the development stage of the program, 512 by 512 prototype baseline and 128 by 128 prototype high dynamic range (HDR) arrays have been fabricated separately. Characterization measurements to include: spectral output, dynamic range capability, apparent temperature, rise time, fall time, cross talk, and current consumption have been accomplished on the prototype baseline and HDR arrays at the Kinetic Kill Vehicle Hardware-in-the-Loop Simulator (KHILS) Facility and the Guided Weapons Evaluation Facility (GWEF). Results from the measurements show the HDR array dynamic range is an order of magnitude greater than its predecessor. Other parameters such as droop, rise time, etc., either meet or are close to meeting system specifications. The final design of the arrays is currently in progress based on these results.

Jones, Lawrence E.; Olson, Eric M.; Goldsmith, George C., II

1996-06-01

426

Wideband acoustic immittance normative data: ethnicity, gender, aging, and instrumentation.  

PubMed

This article describes the effect of ethnicity, gender, aging, and instrumentation on wideband acoustic immittance (WAI). This is an important topic to investigate as the goal of any audiological test is optimize the test's sensitivity and specificity. One way to improve the test's sensitivity and specificity is to reduce the variability of the normative data. The impact of the aforementioned demographic characteristics on WAI norms has been reviewed, and where applicable its potential impact on clinical outcome has been discussed. Overall, differences observed between Caucasian and Chinese ethnic groups in adults population may warrant the use of ethnicity-specific norms especially for detection of otosclerosis; however, these differences in the school-aged children are not large enough to warrant the use of ethnicity-specific norms. It is important to explore whether the observed differences between Caucasian and Chinese ethnic groups is due to body-size indices and whether these differences can be replicated in other East Asian ethnic groups that share similar body-size indices. The differences observed between school-aged children and adults could also potentially impact clinical decision analysis. Therefore, use of age-specific norm is recommended. The differences in WAI between different systems are not clinically significant, and the use of instrument-specific norms does not result in improved test performance at least for the detection of otosclerosis. However, measuring WAI at ambient pressure (static) or at pressure corresponding to the peak (dynamic mode) could potentially impact the normative data and may prove to be clinically useful in cases of negative and positive middle ear pressure. PMID:23900176

Shahnaz, Navid; Feeney, M Patrick; Schairer, Kim S

2013-07-01

427

Auroral spectral estimation with wide-band color mosaic CCDs  

NASA Astrophysics Data System (ADS)

Optical aurora can be structured over a wide range of spatial and temporal scales with spectral features that depend on the energy of precipitating particles. Scientific studies typically combine data from multiple instruments that are individually optimized for spatial, spectral, or temporal resolution. One recent addition combines all-sky optics with color mosaic CCD (charge-coupled device) detectors that use a matrix of different wide-band micro-filters to produce an image with several (often three) color channels. These devices provide sequences of two dimensional multispectral luminosity with simultaneous exposure of all color channels allowing interchannel comparison even during periods with rapidly varying aurora. At present color auroral image data are primarily used for qualitative analysis. In this study a quantitative approach based on Backus-Gilbert linear inversion was used to better understand the effective spectral resolution of existing and proposed instruments. Two spectrally calibrated commercial detectors (Sony ICX285AQ and ICX429AKL) with very different color mosaics (RGB (red, green, blue) vs. CYGM (cyan, yellow, green, magenta)) were found to have very similar spectral resolution: three channels with FWHM (full-width half-maximum) ?100 nm; a NIR (near infrared) blocking filter is important for stabilizing inversion of both three-channel configurations. Operating the ICX429AKL in a noninterlaced mode would improve spectral resolution and provide an additional near infrared channel. Transformations from arbitrary device channels to RGB are easily obtained through inversion. Simultaneous imaging of multiple auroral emissions may be achieved using a single-color camera with a triple-pass filter. Combinations of multiple cameras with simple filters should provide ~50 nm resolution across most of the visible spectrum. Performance of other instrument designs could be explored and compared using the same quantitative framework.

Jackel, B. J.; Unick, C.; Syrjäsuo, M. T.; Partamies, N.; Wild, J. A.; Woodfield, E. E.; McWhirter, I.; Kendall, E.; Spanswick, E.

2014-06-01

428

Free space optical communications for ultra high-capacity PON system  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate a set of ultra-high capacity free space passive optical networks (PONs) using quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (16-QAM) Nyquist pulse shaped and orthogonal frequency-division multiplexing (OFDM) modulations. Moreover, these technologies support up to 10 Gb/s services per user and allow a smooth and full integration between fiber and optical wireless access networks.

Shahpari, Ali; Sousa, Artur N.; Ferreira, Ricardo; Lima, Mário; Teixeira, António

2014-08-01

429

A Novel Ultra-Low Power (ULP) Low Noise Amplifier using Differential Inductor Feedback  

Microsoft Academic Search

A novel ultra-low power (ULP) low noise amplifier (LNA) is proposed for low-power radio-frequency (RF) wireless radios. Using the differential inductor feedback structure along with the neutralizing capacitor, this configuration doubles the effective gm of the input transistor, while canceling out the feed forward and LO leakage through the gate-drain capacitor. In this design, the input device is biased to

Amin Shameli; Payam Heydari

2006-01-01

430

Wireless infrared computer control  

NASA Astrophysics Data System (ADS)

Wireless mouse is not restricted by cable"s length and has advantage over its wired counterpart. However, all the mice available in the market have detection range less than 2 meters and angular coverage less than 180 degrees. Furthermore, commercial infrared mice are based on track ball and rollers to detect movements. This restricts them to be used in those occasions where users want to have dynamic movement, such as presentations and meetings etc. This paper presents our newly developed infrared wireless mouse, which has a detection range of 6 meters and angular coverage of 180 degrees. This new mouse uses buttons instead of traditional track ball and is developed to be a hand-held device like remote controller. It enables users to control cursor with a distance closed to computer and the mouse to be free from computer operation.

Chen, George C.; He, Xiaofei

2004-04-01

431

ited Wireless Sensor Networks  

Microsoft Academic Search

We consider the joint optimal design of the physical, medium access control (MAC), and routing layers to maximize the lifetime of energy-constrained wireless sensor networks. The problem of computing lifetime-optimal routing flow, link schedule, and link transmission powers for all active time slots is formulated as a non-linear optimization problem. We first restrict the link schedules to the class of

Ritesh Madan; Shuguang Cui; Sanjay Lall; Andrea Goldsmith

432

Wireless and passive temperature indicator utilizing the large hysteresis of magnetic shape memory alloys  

NASA Astrophysics Data System (ADS)

An ultra-low cost, wireless magnetoelastic temperature indicator is presented. It comprises a magnetostrictive amorphous ribbon, a Ni-Mn-Sn-Co magnetic shape memory alloy with a highly tunable transformation temperature, and a bias magnet. It allows to remotely detect irreversible changes due to transgressions of upper or lower temperature thresholds. Therefore, the proposed temperature indicator is particularly suitable for monitoring the temperature-controlled supply chain of, e.g., deep frozen and chilled food or pharmaceuticals.

Bergmair, Bernhard; Liu, Jian; Huber, Thomas; Gutfleisch, Oliver; Suess, Dieter

2012-07-01

433

Portable Wireless Sensors for Object Usage Sensing in the Home: Challenges and Practicalities  

Microsoft Academic Search

A low-cost kit of stick-on wireless sensors that transmit data indicating whenever various objects are being touched or used might aid ubiquitous computing research efforts on rapid prototyping, context-aware computing, and ultra-dense object sensing, among others. Ideally, the sensors would be small, easy-to-install, and affordable. The sensors would reliably recognize when specific objects are manipulated, despite vibrations produced by the

Emmanuel Munguia Tapia; Stephen S. Intille; Kent Larson

2007-01-01

434

A multi-channel low-power system-on-chip for single-unit recording and narrowband wireless transmission of neural signal.  

PubMed

This paper reports a multi-channel neural recording system-on-chip (SoC) with digital data compression and wireless telemetry. The circuit consists of a 16 amplifiers, an analog time division multiplexer, an 8-bit SAR AD converter, a digital signal processor (DSP) and a wireless narrowband 400-MHz binary FSK transmitter. Even though only 16 amplifiers are present in our current die version, the whole system is designed to work with 64 channels demonstrating the feasibility of a digital processing and narrowband wireless transmission of 64 neural recording channels. A digital data compression, based on the detection of action potentials and storage of correspondent waveforms, allows the use of a 1.25-Mbit/s binary FSK wireless transmission. This moderate bit-rate and a low frequency deviation, Manchester-coded modulation are crucial for exploiting a narrowband wireless link and an efficient embeddable antenna. The chip is realized in a 0.35- ?m CMOS process with a power consumption of 105 ?W per channel (269 ?W per channel with an extended transmission range of 4 m) and an area of 3.1 × 2.7 mm(2). The transmitted signal is captured by a digital TV tuner and demodulated by a wideband phase-locked loop (PLL), and then sent to a PC via an FPGA module. The system has been tested for electrical specifications and its functionality verified in in-vivo neural recording experiments. PMID:21096380

Bonfanti, A; Ceravolo, M; Zambra, G; Gusmeroli, R; Spinelli, A S; Lacaita, A L; Angotzi, G N; Baranauskas, G; Fadiga, L

2010-01-01

435

Wireless Communications: Trends and Challenges  

Microsoft Academic Search

Emerging demands for high data rate services and high spectral efficiency are the key driving forces for the con- tinued technology evolution in wireless communications. Third generation (3G) mobile communication systems have already been commercially deployed in certain parts of the world to meet the initial demand for high data rate packet-based services including wireless internet access. Recently, several advancements

Kapila C. Wavegedara; Gaurav Bansal; Praveen Kaligineedi; Majid Khabbazian; Ashok K. Karomokar; Mamunur Rashid; Hugues Mercier; Vijay K. Bhargava

436

Building a secured wireless LAN  

Microsoft Academic Search

The security of wireless LANs has been a source of concern for businesses and individuals who are aware of its advantages due to its flexibility. With the increase in the use of wireless LANs for enterprises and homes, where information assets are shared continually, security is of the essence. With the increase in ecommerce and e- services, there is the

Rajni Pamnani; Pramila Chawan

2009-01-01

437

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

Fred Sabins

2002-01-23

438

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that will be performed for analyzing the alkali-silica reactivity of ULHS in cement slurries, as well as the results of Field Tests 1 and 2.

Fred Sabins

2002-10-31

439

A Parametric Analytical Diffusion Model for Indoor Ultra-Wideband Received Signal Majid A. Nemati Robert A. Scholtz  

E-print Network

be fine tuned to the environment Ã? Narrowband indoor fading channel is the special case of the proposed, reflected probably from different materials with unrelated reflection and absorption coefficients Ã? in the environment results in stronger reflections and higher probability of large innovation values ( ) tt d

Southern California, University of

440

IEEE TRANSACTIONS ON ADVANCED PACKAGING, VOL. 30, NO. 3, AUGUST 2007 533 Design and Fabrication of Ultra-Wideband  

E-print Network

(LCP) flex. Fabrication techniques are demonstrated for processing these commercially available LCP thin-films by standard PCB equipments. Variations in the LCP thin-film thickness are characterized imbalance less than 1.2 dB and 2 , respectively. These baluns are ideal for applications in UWB

Pham, Anh-Vu

441

Development of ultra-high sensitivity wide-band gap UV-EUV detectors at NASA Goddard Space Flight Center  

Microsoft Academic Search

Rapid progress in the AlGaN (Eg=3.4-6.2eV), 4H-SiC (Eg=3.2eV) and ZnMgO (Eg=2.8-7.9eV) material systems over the last five years has led to the demonstration of a number of opto-electronic devices. These wide energy band gap devices offer several key advantages for space applications, over conventional Si (Eg=1.1eV) based devices, such as visible-blind detection, high thermal stability, better radiation hardness, high breakdown

S. Aslam; F. Yan; D. E. Pugel; D. Franz; L. Miko; F. Herrero; M. Matsumara; S. Babu; C. M. Stahle

2005-01-01

442

Abstract--This paper investigates a ranging method employing Ultra wideband (UWB) pulses under the existence of the line of  

E-print Network

applications such as see-through-the-wall, medical imaging, and collision avoidance. Previous ranging reduces noise of the received signals corrupted by the statistically zero mean AWGN. The proposed method error due to imperfect TOA estimation from imperfect synchronization. Sources of inter

Ha, Dong S.

443

A CPW-Fed Printed Loop Antenna for Ultra-Wideband Applications, and its Linear-Array Performance  

Microsoft Academic Search

A small CPW-fed loop antenna is described. The single antenna has a measured relative impedance bandwidth of 70%. Radiation patterns show stable co-polar and low cross-polar characteristics within the specified bandwidth. The small size of the radiator (0.5? at 13.6 GHz) makes it suitable for being used in linear-array applications. The linear-array performance of the antenna is investigated by means

F. M. Tanyer-Tigrek; I. E. Lager; Leonardus P. Ligthart

2010-01-01

444

Design of a 3.1-4.8 GHZ RF front-end for an ultra wideband receiver  

E-print Network

frequency band of 3.168 GHz ? 10.6 GHz is an emerging solution to this with data rates of 110, 200 and 480 Mbps. Initially, UWB mode I devices using only 3.168 GHz ? 4.752 GHz have been proposed. Low Noise Amplifier (LNA) and I-Q mixers are key components...

Sharma, Pushkar

2006-08-16

445

A wide-band modeling of DC-DC two-transistor flyback converter  

Microsoft Academic Search

This paper presents results on wide-band modeling of DC-DC flyback converter. The model of converter is composed of detailed models of transformer, transistors, diodes and tracks. Parameter identification methods are based on manufacturer data sheet and externally measurable characteristics and parameters. The templates of models are written in the MAST and implemented for simulation in the SABER simulator. Validation of

Marek Turzynski; Maciej Haras; Grzegorz Kostro; Piotr Musznicki

2011-01-01

446

A Linear, Wideband, Low-Noise Amplifier Stage for Use in Nuclear Pulse Amplifiers  

Microsoft Academic Search

The design evolution of a wideband voltage-sensitive amplifier stage is presented. For the basic stage, including a new driver configuration and overload control circuit, three basic input sections are considered; the first section consists of differentially connected bipolar transistors for use with low generator impedances, the second consists of medium-transconductance FETs to allow larger coupling time constants, and the third

J. K. Millard; T. V. Blalock

1970-01-01

447

Wideband and low dispersion slow light by chirped photonic crystal coupled waveguide  

E-print Network

Wideband and low dispersion slow light by chirped photonic crystal coupled waveguide Daisuke Mori coupled waveguide, which allows more robust slow light with lower loss. For this device, unique photonic, and J. Yonekura, "Observation of light propagation in photonic crystal optical waveguides with bends

Baba, Toshihiko

448

Design of wide-band aperture-stacked patch microstrip antennas  

Microsoft Academic Search

A variation of the aperture-coupled stacked patch microstrip antenna is presented, which greatly enhances its bandwidth. Bandwidths of up to one octave have been achieved. The impedance behavior of this antenna is compared with that of other wide-band microstrip radiators. Matching techniques for the antenna are presented and their relative merits discussed. The effects of varying several key physical parameters

S. D. Targonski; R. B. Waterhouse; D. M. Pozar

1998-01-01

449

Design of wideband attenuation devices based on Sonic Crystals made of multi-phenomena scatterers  

E-print Network

Design of wideband attenuation devices based on Sonic Crystals made of multi-phenomena scatterers V 283 #12;Sonic Crystals (SCs) are periodic structures of solid scatterers embedded in a fluid. Perhaps and acoustics respectively. In the case of phononics, there is a particular system, called Sonic Crystal (SC

Paris-Sud XI, Université de

450

Small Corona Cage for Wideband HVac Radio Noise Studies: Rationale and Critical Design  

Microsoft Academic Search

Corona cages are used in overhead power line studies to investigate physical mechanisms involved in corona discharge and to predict radio noise generation. In this paper, we design a small laboratory corona cage to investigate wideband radio noise generation on practical HVac conductor bundles. We introduce and describe cage design criteria including the insulation of the cage mesh. Our measurement

Rodney G. Urban; Howard C. Reader; Jacobus P. Holtzhausen

2008-01-01

451

Low power architecture and circuit techniques for high boost wideband Gm-C filters  

E-print Network

of such 'Equalizing Filter' (boost filter) for read channel applications. Specifically, a 330MHz, 5th order Gm-C continuous time lowpass filter with 24dB boost is designed. Existing architectures are found to be unsuitable for low power, wideband and high boost...

Gambhir, Manisha

2007-09-17

452

The signal subspace approach for multiple wide-band emitter location  

Microsoft Academic Search

The rational vector space generalization of the signal subspace approach is presented and applied to the estimation of multiple wide-band emitter locations from the signals received at multiple sensors. The signal subspace and array manifold concepts first introduced by Schmidt are generalized to rational vector space. These concepts are used to develop the rational signal subspace theory and prove the

Guaning Su; MARTIN MORF

1983-01-01

453

Trinuclear Gold(I) Triazolates: A New Class of Wide-Band Phosphors and Sensors  

E-print Network

Trinuclear Gold(I) Triazolates: A New Class of Wide-Band Phosphors and Sensors Chi Yang, Marc, Buffalo, New York 14260-3000 Received May 30, 2006 A new cyclic gold(I) triazolate trimer, [Au(3,5-i-Pr2Tz, pyrazolate, and carbeniate4-6 but not triazolate bridging ligands.8a Compared to imidazole and pyrazole, 1

Coppens, Philip

454

Wideband Antenna With Conductive Textile Radiators for a Dual-Sensor Subsurface Detection System  

Microsoft Academic Search

A wideband antenna with conductive textile radia- tors (WACTR) is investigated for a pulsed dual-sensor subsurface detection system, which is composed of a ground penetrating radar (GPR) sensor and an electromagnetic induction (EI) sensor. It is demonstrated that undesired clutter of the EI sensor arising from the metallic mass and conductivity of the GPR antenna radiators can be removed by

A. Oral Salman; Emrullah Bicak; Mehmet Sezgin

2011-01-01

455

Binaural detection with narrowband and wideband reproducible noise maskers. IV. Models using interaural time,  

E-print Network

Binaural detection with narrowband and wideband reproducible noise maskers. IV. Models using' performance for the dichotic condition. In this study, two binaural models based on combinations of interaural of an ongoing series of experimental and model- ing studies of binaural detection (Evilsizer et al., 2002; Zheng

Carney, Laurel H.

456

Rocket measurements of auroral electron density irregularities in support of the Defense Nuclear Agency wideband satellite  

Microsoft Academic Search

In situ measurements of electron density irregularities in the auroral E and F regions were conducted in support of the DNA Wideband satellite. The results from the two rocket probes that were flown in conjunction with nighttime overpasses of the satellite are reported in detail. Significant regions of irregular plasma density fluctuations were detected on both flights, but with somewhat

K. D. Baker; J. C. Ulwick; M. C. Kelley; L. C. Howlett; N. Grossbard

1978-01-01

457

Concealed explosive detection on personnel using a wideband holographic millimeter-wave imaging system  

Microsoft Academic Search

A novel wideband millimeter-wave imaging system is presently being developed at Pacific Northwest National Laboratory (PNNL) that will allow rapid inspection of personnel for concealed explosives, handguns, or other threats. Millimeter- wavelength electromagnetic waves are effective for this application since they readily penetrate common clothing materials, while being partially reflected from the person under surveillance as well as any concealed

D. M. Sheen; D. L. McMakin; H. D. Collins; R. H. Severtsen

458

CMOS Low-Noise Amplifier Analysis and Optimization for Wideband Applications  

Microsoft Academic Search

A low-noise amplifier design for the wideband applications is discussed in this paper. A typical inductively degenerated common source (IDCS) LNA is optimal for narrowband systems with reception band of few hundred MHz. However, ultrawideband systems with multiple GHz bandwidth set new requirements for the LNA. In this paper the usability of IDCS topology for UWB system is studied. Different

Jouni Kaukovuori; Jussi Ryynanen; K. A. I. Halonen

2006-01-01

459

Some physical layer issues of wide-band cognitive radio systems  

Microsoft Academic Search

Recent study by FCC spectrum policy task force (SPTF) found that while the available spectrum becomes increasingly scarce, the assigned spectrum is significantly underutilized. Cognitive radio technology holds the key promise to solve such problems. In this paper, we investigate some physical layer issues of wide-band cognitive radio systems. Specifically, we discuss the physical layer signal structure to support flexible

Haiyun Tang

2005-01-01

460

A wideband analog multi-resolution spectrum sensing (MRSS) technique for cognitive radio (CR) systems  

Microsoft Academic Search

Spectrum sensing technology is most vital to the implementation of a CR system using dynamic spectrum resource management. This paper suggested a CR system architecture with a wideband dual-stage spectrum sensing technique - a coarse and a fine spectrum sensing. Specifically, the coarse spectrum sensing technique adopted wavelet transforms in this architecture to provide a multi-resolution spectrum sensing (MRSS) feature.

Youngsik Hur; Jongmin Park; W. Woo; Kyutae Lim; Chang-ho Lee; Hyoungsoo Kim; Joy Laskar

2006-01-01

461

A wideband frequency synthesizer for built-in self testing of analog integrated circuits  

E-print Network

leading to the use of built-in self-tests (BISTs). The frequency generator or frequency synthesizer is a key element of the BIST. It generates the clock frequencies needed for testing. A wide-band frequency synthesizer is designed in the project...

Yan, Wenjian

2004-11-15

462

A new statistical wideband spatio-temporal channel model for 5GHz band WLAN systems  

Microsoft Academic Search

In this paper, a new statistical wideband indoor channel model which incorporates both the clustering of multipath components (MPCs) and the correlation between the spatial and temporal domains is proposed. The model is derived based on measurement data collected at a carrier frequency of 5.2 GHz in three different indoor scenarios and is suitable for performance analysis of HIPERLAN\\/2 and

Chia-Chin Chong; Chor-Min Tan; David I. Laurenson; Stephen McLaughlin; Mark A. Beach; Andrew R. Nix

2003-01-01

463

SynFace Phone Recognizer for Swedish Wideband and Narrowband Speech  

E-print Network

was developed for telephone conversation support. Presently, we are extend- ing the scope of SynFace to otherSynFace Phone Recognizer for Swedish Wideband and Narrowband Speech Samer al Moubayed KTH Centre head SynFace on different Swedish da- tabases and bandwidth. The work involves training SynFace

Beskow, Jonas

464

Ultra supercritical steamside oxidation  

SciTech Connect

Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, Margaret

2005-01-01

465

Industrial Control using Wireless Sensor Networks  

Microsoft Academic Search

Wireless sensor networks have been an active research topic during the past few years. Researchers have conducted extensive studies on various aspects of wireless sensor networks: information dissemination [4], energy-efficient routing [1] and security [8], etc. In addition, wireless sensor networks have been successfully applied to environmental and wildlife habitat monitoring. However, real time control over wireless network systems still

Kamran Khakpour; M. H. Shenassa

2008-01-01

466

The wireless Internet today and tomorrow  

Microsoft Academic Search

I review the current technology for accessing the Web using wireless handheld devices. There is a lot of excitement in the news about the wireless Internet. The current technology is limited, but fortunately, everything is about to change in the wireless world. We are about to face changes across the board in wireless Internet access: infrastructure, devices, and user interfaces

Giovanni Flammia

2000-01-01

467

A Robust Separating and Tracking Method on Two Wideband Sources by Subspace Rotation with One Vector Hydrophone  

NASA Astrophysics Data System (ADS)

It has been proved theoretically that two incompletely correlated sources can be identified by linear signal processing methods. However, it is difficult in practice. A new method to separate two wideband sources with one vector sensor is presented in this paper. The method is the combination of subspace rotation and spatial matched filter. Simulations show that this method is insensitive to the initial azimuth error, independent of signal spectrum, and better man wideband focusing subspace methods at low SNR. The sea trial is performed and the experiment results show that the proposed method is effective to separate and track two wideband sources in the underwater environment.

Wang, De-jun; Li, Feng-hua

2010-09-01

468

75 FR 8400 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...  

Federal Register 2010, 2011, 2012, 2013

...Software, Wireless Handheld Devices and Battery Packs; Notice of Investigation AGENCY...software, wireless handheld devices and battery packs by reason of infringement of certain...software, wireless handheld devices or battery packs that infringe one or more of...

2010-02-24

469

Proactive mobile wireless networks : an infrastructureless wireless network architecture for delay-sensitive applications  

E-print Network

Infrastructureless wireless networks are an important class of wireless networks that is best suited for scenarios where there is temporary and localized telecommunication demand. Such networks consist of wireless devices ...

Dai, Lillian Lei, 1978-

2008-01-01

470

Wireless Headset Communication System  

NASA Technical Reports Server (NTRS)

System combines features of pagers, walkie-talkies, and cordless telephones. Wireless headset communication system uses digital modulation on spread spectrum to avoid interference among units. Consists of base station, 4 radio/antenna modules, and as many as 16 remote units with headsets. Base station serves as network controller, audio-mixing network, and interface to such outside services as computers, telephone networks, and other base stations. Developed for use at Kennedy Space Center, system also useful in industrial maintenance, emergency operations, construction, and airport operations. Also, digital capabilities exploited; by adding bar-code readers for use in taking inventories.

Lau, Wilfred K.; Swanson, Richard; Christensen, Kurt K.

1995-01-01

471

Display Size Wireless LAN  

E-print Network

2200 Celeron M 1.30 GHz 1.24GB 40GB 14 inch 2.8kg WinXP Pro - /Wireless F002 TOSHIBA dynabookSS Pentium.08kg WinXP Pro - - F005 TOSHIBA dynabook PASX190NX Pentium M 753 1.2GHz(2MB) 256MB 60GB 12.1 inch 1GB 14 inch 3.0Kg WinXP Pro - - F033 TOSHIBA dynabook Satellite J32 Celeron M 1.30GHz 256MB 40GB 14

Katsumoto, Shingo

472

Deployable wireless Fresnel lens  

NASA Technical Reports Server (NTRS)

Apparatus and methods for enhancing the gain of a wireless signal are provided. In at least one specific embodiment, the apparatus can include a screen comprised of one or more electrically conductive regions for reflecting electromagnetic radiation and one or more non-conductive regions for permitting electromagnetic radiation therethrough. The one or more electrically conductive regions can be disposed adjacent to at least one of the one or more non-conductive regions. The apparatus can also include a support member disposed about at least a portion of the screen. The screen can be capable of collapsing by twisting the support member in opposite screw senses to form interleaved concentric sections.

Kennedy, Timothy F. (Inventor); Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Lin, Gregory Y. (Inventor)

2013-01-01

473

Addressing the Emerging Wireless Bandwidth Crisis and the Need for Power-Efficient Bandwidth: Prospects for mm-Wave Radio Technology  

E-print Network

crisis. The main promise of mm-wave radio is that it offers a route to power-efficient bandwidth of high-bandwidth, low power mm-wave networks. Short Biography of the Presenter Dr. Daniel Foty has some processing, wired/wireless communications, and ultra-low-power design. A serial entrepreneur, he is currently

474

The 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC'07) IMPLEMENTING BACKSCATTER RADIO FOR WIRELESS SENSOR NETWORKS  

E-print Network

when low bit-rate, ultra low-cost sen- sors are required. I INTRODUCTION The technique of radio the reflection by controlling their own reflection coefficient [1]. This leads to low-complexity, low-power of backscatter radio in low-cost, en- ergy efficient wireless sensor networks. For example, we en- vision several

475

Observation of Ultra-high-energy Cosmic Rays with the ANITA Balloon-borne Radio Interferometer  

E-print Network

We report the observation of sixteen cosmic ray events of mean energy of $1.5 \\times 10^{19}$ eV, via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present the first ultra-wideband, far-field measurements of the radio spectral density of geosynchrotron emission in the range from 300-1000 MHz. The emission is 100% linearly polarized in the plane perpendicular to the projected geomagnetic field. Fourteen of our observed events are seen to have a phase-inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon.

Hoover, S; Gorham, P W; Grashorn, E; Allison, P; Barwick, S W; Beatty, J J; Belov, K; Besson, D Z; Binns, W R; Chen, C; Chen, P; Clem, J M; Connolly, A; Dowkontt, P F; DuVernois, M A; Field, R C; Goldstein, D; Vieregg, A G; Hast, C; Hebert, C L; Israel, M H; Javaid, A; Kowalski, J; Learned, J G; Liewer, K M; Link, J T; Lusczek, E; Matsuno, S; Mercurio, B C; Miki, C; Mio?inovi?, P; Naudet, C J; Ng, J; Nichol, R J; Palladino, K; Reil, K; Romero-Wolf, A; Rosen, M; Ruckman, L; Saltzberg, D; Seckel, D; Varner, G S; Walz, D; Wu, F

2010-01-01

476

Crustal heterogeneities deduced from wideband and Network MT measurements around the Niigata-Kobe Tectonic Zone, Chubu District, Japan  

Microsoft Academic Search

Wideband magnetotelluric (MT) soundings were carried out around the concentrated deformation zone, Chubu District, Japan (NKTZ: Niigata-Kobe Tectonic Zone, e.g. Sagiya et al., 2000). The NKTZ becomes one of important target areas in \\

R. Yoshimura; M. Uyeshima; N. Oshiman; H. Toh; Y. Ogawa; T. Ogawa; S. Yamaguchi

2007-01-01

477

CCEC Seminar Wireless Sensors for SemiconductorWireless Sensors for Semiconductor  

E-print Network

CCEC Seminar Wireless Sensors for SemiconductorWireless Sensors for Semiconductor Manufacturing in semiconductor manufacturing. These sensors are fully self-contained with on board power, communications

Akhmedov, Azer

478

Biomonitoring with Wireless Communications  

SciTech Connect

This review is divided into three sections: technologies for monitoring physiological parameters; biosensors for chemical assays and wireless communications technologies including image transmissions. Applications range from monitoring high risk patients for heart, respiratory activity and falls to sensing levels of physical activity in military, rescue, and sports personnel. The range of measurements include, heart rate, pulse wave form, respiratory rate, blood oxygen, tissue pCO2, exhaled carbon dioxide and physical activity. Other feasible measurements will employ miniature chemical laboratories on silicon or plastic chips. The measurements can be extended to clinical chemical assays ranging from common blood assays to protein or specialized protein measurements (e.g., troponin, creatine, and cytokines such as TNF and IL6). Though the feasibility of using wireless technology to communicate vital signs has been demonstrated 32 years ago (1) it has been only recently that practical and portable devices and communications net works have become generally available for inexpensive deployment of comfortable and affordable devices and systems.

Budinger, Thomas F.

2003-03-01

479

Challenges on the design and evaluation of wireless sensor platform for real-world applications  

NASA Astrophysics Data System (ADS)

This paper first presents two designs of wireless sensor platforms for real-life applications, Eco and DuraNode. Eco is an ultra-compact, power-efficient and expandable wireless sensor platform. DuraNode is a Wi-Fi based WSN platform, especially designed for civil engineering structural health monitoring. Next, we propose quantitative evaluation tools for wireless sensor networks: Empro and B#. Empro is an environment/energy emulation and evaluation tool and B# is a battery emulation and power profiling instrument. Empro emulates all stimuli to a wireless sensor node including not only all sensory inputs but also power sources and radio signals, allowing the sensor node to run as if it was operating in the actual environment, but with full reproducibility. We also show two efficient energy harvesting platform: Puma and AmbiMax. Puma is a novel technique for matching power sources and power consumers. AmbiMax is an autonomous energy harvesting platform for multi-supply wireless sensor nodes.

Park, Chulsung

480

Broadcast of four HD videos with LED ceiling lighting: optical-wireless MAC  

NASA Astrophysics Data System (ADS)

The European project "hOME Gigabit Access Network" (OMEGA) targeted various wireless and wired solutions for 1 Gbit/s connectivity in Home Area Networks (HANs). One objective was to evaluate the suitability of optical wireless technologies in two spectral regions: visible light (visible-light communications - VLC) and near infrared (infrared communications - IRC). Several demonstrators have been built, all of them largely relying on overthe- shelf components. The demonstrators included a "wide-area" VLC broadcast link based on LED ceiling lighting and a laser-based high-data-rate "wide-area" IRC prototype. In this paper we discuss an adapted optical-wireless media-access-control (OWMAC) sublayer, which was developed and implemented during the project. It is suitable for both IRC and VLC. The VLC prototype is based on DMT signal processing and provides broadcasting at { 100 Mbit/s over an area of approximately 5 m2. The IRC prototype provides {300 Mbit/s half-duplex communication over an area of approximately 30 m2. The IRC mesh network, composed of one base station and two terminals, is based on OOK modulation, multi-sector transceivers, and an ultra-fast sector switch. After a brief discussion about the design of the optical-wireless data link layer and the optical-wireless switch (OWS) card, we address the card development and implementation. We also present applications for the VLC and IRC prototypes and measurement results regarding the MAC layer.

Bouchet, Olivier; Porcon, Pascal; Gueutier, Eric

2011-09-01

481

Wireless Communications in Smart Grid  

NASA Astrophysics Data System (ADS)

Communication networks play a crucial role in smart grid, as the intelligence of this complex system is built based on information exchange across the power grid. Wireless communications and networking are among the most economical ways to build the essential part of the scalable communication infrastructure for smart grid. In particular, wireless networks will be deployed widely in the smart grid for automatic meter reading, remote system and customer site monitoring, as well as equipment fault diagnosing. With an increasing interest from both the academic and industrial communities, this chapter systematically investigates recent advances in wireless communication technology for the smart grid.

Bojkovic, Zoran; Bakmaz, Bojan

482

Ultra supercritical steamside oxidation  

SciTech Connect

Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, which are part of the U.S. Department of Energy's Vision 21 goals. Most current coal power plants in the U.S. operate at a maximum steam temperature of 538 C. However, new supercritical plants worldwide are being brought into service with steam temperatures of up to 620 C. Vision 21 goals include steam temperatures of up to 760 C. This research examines the steamside oxidation of advanced alloys for use in USC systems. Emphasis is placed on alloys for high- and intermediate-pressure turbine sections. Initial results of this research are presented.

Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, M.; Alman, David A.; Ochs, Thomas L.

2004-01-01

483

Ultra-Deepwater Production Systems  

Microsoft Academic Search

The report herein is a summary of the work performed on three projects to demonstrate hydrocarbon drilling and production methods applicable to deep and ultra deepwater field developments in the Gulf of Mexico and other like applications around the world. This work advances technology that could lead to more economic development and exploitation of reserves in ultra-deep water or remote

Ken L. Smith; Marc E. Leveque

2005-01-01

484

Wireless transfer of electric power  

E-print Network

In this dissertation, I describe the design and construction of a system which can transfer electric power wirelessly. This is accomplished using inductive, near-field, non-radiative coupling between self-resonant copper ...

Moffatt, Robert Alexander

2009-01-01

485

Wireless Damage Location Sensing System  

NASA Technical Reports Server (NTRS)

A wireless damage location sensing system uses a geometric-patterned wireless sensor that resonates in the presence of a time-varying magnetic field to generate a harmonic response that will experience a change when the sensor experiences a change in its geometric pattern. The sensing system also includes a magnetic field response recorder for wirelessly transmitting the time-varying magnetic field and for wirelessly detecting the harmonic response. The sensing system compares the actual harmonic response to a plurality of predetermined harmonic responses. Each predetermined harmonic response is associated with a severing of the sensor at a corresponding known location thereof so that a match between the actual harmonic response and one of the predetermined harmonic responses defines the known location of the severing that is associated therewith.

Woodard, Stanley E. (Inventor); Taylor, Bryant Douglas (Inventor)

2012-01-01

486

Interference Games in Wireless Networks  

Microsoft Academic Search

We present a game-theoretic approach to the study of scheduling communications in wireless networks and introduce and study a class of games that we call Interference Games. In our setting, a player can successfully transmit if it \\

Vincenzo Auletta; Luca Moscardelli; Paolo Penna; Giuseppe Persiano

2008-01-01

487

Embracing interference in wireless systems  

E-print Network

The wireless medium is a shared resource. If nearby devices transmit at the same time, their signals interfere, resulting in a collision. In traditional networks, collisions cause the loss of the transmitted information. ...

Gollakota, Shyamnath (Shyamnath Venkata Satyasrisai)

2013-01-01

488

Skill Standards for Wireless Telecommunications  

NSDL National Science Digital Library

Developing and implementing strong educational programs are essential steps to take toward affirmatively responding to the shortage of qualified workers for the wireless industry. Community and technical colleges have an enviable opportunity to respond quickly and creatively to wireless manpower supply gaps and manpower shortages. Key to this effort, however, is the necessity to identify core skills and knowledge bases for technicians and engineers. Merely training individuals is not a sufficient response to the need for skilled workers. Achieving consistently high levels of quality both in product and in productivity is an imperative in all sectors of the wireless industry. This realization in turn underscores the need for industry-driven standards for the skill development of workers. For Seattle Central Community College, North Seattle Community College, Bellevue Community College and their industry and labor partners, identifying generic skills and requisite and unique wireless skills and abilities through the skill standards process is tantamount to the task of developing educational programs that prepare individuals for the wireless workplace. The wireless skill standards have been developed at a critical timesignificant changes in local and global wireless technology require clearly articulated standards for both product and employee performance. The outcome of this process is critical to the ability of companies to hire and retain excellent RF talent in a highly competitive market. Both industry and labor recognize the importance of clearly articulated universal skills as a basis for the preparation of qualified and competent workers for the industry, and they will be the ultimate beneficiaries of the results of the wireless skill standards project. Target Audience: 2-4 Year College Faculty/Administrators

2010-01-04

489

Biosensing platforms for wireless health  

NASA Astrophysics Data System (ADS)

Recently there has been a rapid growth in a new area of research known asWireless Health.1 By leveraging stateof- the-art microelectronics and wireless technology, novel biosensing platforms can potentially be widely deployed in various healthcare applications that involve long-term patient monitoring. This paper provides a summary on the development and application of a specific type of biosensing platform known as wearable sensors.

Au, Lawrence K.; Kaiser, William J.

2009-08-01

490

Coverage in Wireless Sensor Networks  

Microsoft Academic Search

\\u000a Ad-hoc networks of devices and sensors with (limited) sensing and wireless communication capabilities are becoming increasingly\\u000a available for commercial and military applications. The first step in deploying these wireless sensor networks is to determine,\\u000a with respect to application-specific performance criteria, (i) in the case that the sensors are static, where to deploy or\\u000a activate them; and (ii) in the case

Jennifer C. Hou; David K. Y. Yau; Chris Y. T. Ma; Yong Yang; Honghai Zhang; I-Hong Hou; Nageswara S. V. Rao; Mallikarjun Shankar

2009-01-01

491

Wireless Infrared Data Link  

NASA Technical Reports Server (NTRS)

Infrared transmitter and receiver designed for wireless transmission of information on measured physical quantity (for example, temperature) from transducer device to remote-acquisition system. In transmitter, output of transducer amplified and shifted with respect to bias or reference level, then fed to voltage-to-frequency converter to control frequency of repetition of current pulses applied to infrared-light-emitting diode. In receiver, frequency of repetition of pulses converted back into voltage indicative of temperature or other measured quantity. Potential applications include logging data while drilling for oil, transmitting measurements from rotors in machines without using slip rings, remote monitoring of temperatures and pressures in hazardous locations, and remote continuous monitoring of temperatures and blood pressures in medical patients, who thus remain mobile.

Roth, Timothy E.

1995-01-01

492

Wireless Josephson Amplifier  

E-print Network

Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a new wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the $9-11$ GHz band with about $100$ MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

A. Narla; K. M. Sliwa; M. Hatridge; S. Shankar; L. Frunzio; R. J. Schoelkopf; M. H. Devoret

2014-04-19

493

Wireless Josephson amplifier  

NASA Astrophysics Data System (ADS)

Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables, and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the 9-11 GHz band with about 100 MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

2014-06-01

494

A flexible wideband bandpass terahertz filter using multi-layer metamaterials  

NASA Astrophysics Data System (ADS)

We make a flexible wideband bandpass filter at terahertz (THz) frequencies using multi-layer metamaterials. A very flat response in the passband can be obtained since the Fabry-Perot reflection inside the rigid substrate is eliminated. The center frequency is about 0.89 THz with a 3 dB bandwidth of 0.69 THz for normal incidence. The sharp band-edge transitions are 53 and 70 dB/THz to the rejection bands, respectively. The measured average insertion loss is 1.4 dB with a ripple of 0.8 dB. Furthermore, the transmission feature is insensitive to the polarization of incident wave due to the symmetric structure of the unit cell of the metamaterials. Also, it has a small change as the increase of the curvature of the flexible substrate. This result manifests that the multi-layer metamaterials can provide an effective way to design wideband THz devices.

Liang, Lanju; Jin, Biaobing; Wu, Jingbo; Huang, Yi; Ye, Zhihui; Huang, Xiaoming; Zhou, Dong; Wang, Guosheng; Jia, Xiaoqing; Lu, Hai; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng

2013-11-01

495

Double-Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation  

PubMed Central

We demonstrate wide-band ultrafast optical pulse generation at 1, 1.5, and 2 ?m using a single-polymer composite saturable absorber based on double-wall carbon nanotubes (DWNTs). The freestanding optical quality polymer composite is prepared from nanotubes dispersed in water with poly(vinyl alcohol) as the host matrix. The composite is then integrated into ytterbium-, erbium-, and thulium-doped fiber laser cavities. Using this single DWNT–polymer composite, we achieve 4.85 ps, 532 fs, and 1.6 ps mode-locked pulses at 1066, 1559, and 1883 nm, respectively, highlighting the potential of DWNTs for wide-band ultrafast photonics. PMID:24735347

2014-01-01

496

DOA estimation of wideband signals based on slice-sparse representation  

NASA Astrophysics Data System (ADS)

In this article, the direction-of-arrival (DOA) estimation problem of wideband signal sources is studied. We pass the incident signals through a bank of narrowband filters to split the array outputs into several narrowband components. Then, a novel slice-sparse representation model of the joint narrowband array covariance data is proposed in the frequency domain to enforce joint sparsity in the concatenated covariance matrix of all frequencies. Based on the greed matching pursuit algorithm, a multiple measurement slices orthogonal matching pursuit algorithm is proposed to exploit the joint frequency processing in the case of wideband scenarios. The DOA estimation is achieved by joint processing of the array covariance data at different frequency bins. The estimated performance is compared with the representative DOA estimation methods. Simulation experiments are conducted to validate the effectiveness of the proposed method.

Gan, Lu; Wang, Xiaoqing

2013-12-01

497

Simple wideband models for disks and wires in the eddy current approximation  

NASA Astrophysics Data System (ADS)

Wideband electromagnetic induction systems have shown improved false alarm rates when compared with traditional metal detectors. Calibration of these sensors and the development of algorithms for target discrimination could be assisted by a set of models for common targets. In this paper, simple wideband models of the eddy current response for a wire and disk are provided. These are provided in the form of a singularity expansion of the polarizability dyadic. In an effort to make this form more concrete, a major focus of the paper is on relating the terms of the expansion to graphs of the currents present on the disk. The models provided in the paper are based on limiting forms of a cylinder as computed using the body-of-revolutions finite element method. Measured polarizability dyadics are also shown to fit the forms provided reasonably well.

Scott, Waymond R.; McFadden, Michael

2013-05-01

498

The 30/20 Gigahertz transponder study. [wideband multichannel transponders for a communications satellite  

NASA Technical Reports Server (NTRS)

Design features and performance parameters are described for three types of wideband multiple channel satellite transponders for use in a 30/20 GHz communications satellite, which provides high data rate trunking service to ten ground station terminals. The three types of transponder are frequency division multiplex (FDM), time division multiplex (TDM), and a hybrid transponder using a combination of FDM and TDM techniques. The wideband multiple beam trunking concept, the traffic distribution between the trunking terminals, and system design constraints are discussed. The receiver front end design, the frequency conversion scheme, and the local oscillator design are described including the thermal interface between the transponders and the satellite. The three designs are compared with regard to performance, weight, power, cost and initial technology. Simplified block diagrams of the baseline transponder designs are included.

1980-01-01

499

Double-wall carbon nanotubes for wide-band, ultrafast pulse generation.  

PubMed

We demonstrate wide-band ultrafast optical pulse generation at 1, 1.5, and 2 ?m using a single-polymer composite saturable absorber based on double-wall carbon nanotubes (DWNTs). The freestanding optical quality polymer composite is prepared from nanotubes dispersed in water with poly(vinyl alcohol) as the host matrix. The composite is then integrated into ytterbium-, erbium-, and thulium-doped fiber laser cavities. Using this single DWNT-polymer composite, we achieve 4.85 ps, 532 fs, and 1.6 ps mode-locked pulses at 1066, 1559, and 1883 nm, respectively, highlighting the potential of DWNTs for wide-band ultrafast photonics. PMID:24735347

Hasan, Tawfique; Sun, Zhipei; Tan, PingHeng; Popa, Daniel; Flahaut, Emmanuel; Kelleher, Edmund J R; Bonaccorso, Francesco; Wang, Fengqiu; Jiang, Zhe; Torrisi, Felice; Privitera, Giulia; Nicolosi, Valeria; Ferrari, Andrea C

2014-05-27

500

Achieving wideband polarization-independent anomalous reflection for linearly polarized waves with dispersionless phase gradient metasurfaces  

NASA Astrophysics Data System (ADS)

In this letter, we proposed to achieve wideband polarization-independent anomalous reflection for linearly polarized (LP) waves based on the phase gradient metasurface (PGM) with a dispersionless phase gradient. A polarization-keeping metasurface reflector for circularly polarized (CP) waves was firstly presented. Based on the reflector, a reflective PGM was designed to realize dispersionless but adverse phase gradients for left- and right-handed circularly polarized (LCP and RCP, respectively) waves. Under normal incidence, high-efficiency anomalous reflection occurs for both LCP and RCP waves with opposite-signed reflection angles. Under the LP wave incidence, the reflected waves are separated into two beams due to the decomposition of LP waves into LCP and RCP waves. The anomalous reflection of LP waves is independent of the polarization angle. Both the experimental and simulated results are consistent with theoretical predictions, which convincingly verifies the wideband polarization-independent anomalous reflection of LP waves.

Li, Yongfeng; Zhang, Jieqiu; Qu, Shaobo; Wang, Jiafu; Chen, Hongya; Zheng, Lin; Xu, Zhuo; Zhang, Anxue

2014-10-01