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1

A Vehicular Ultra-Wideband Channel Model for Future Wireless IntraVehicle Communications (IVC) Systems  

Microsoft Academic Search

Future wireless intra-vehicle communications (IVC) systems adopting ultra-wideband (UWB) radio are proposed in this paper, which provide onboard passengers with high-speed duplex data exchange services. In this paper, a vehicular UWB channel model is first developed by modifying the IEEE 802.15.3a indoor model to fit into the vehicular environments with dense and concentrated clusters and rays. The main channel statistical

Weidong Xiang

2007-01-01

2

Cooperative Communications in Ultra-Wideband Wireless Body Area Networks: Channel Modeling and System Diversity Analysis  

Microsoft Academic Search

In this paper, we explore the application of cooperative communications in ultra-wideband (UWB) wireless body area networks (BANs), where a group of on-body devices may collaborate together to communicate with other groups of on-body equipment. Firstly, time-domain UWB channel measurements are presented to characterize the body-centric multipath channel and to facilitate the diversity analysis in a cooperative BAN (CoBAN). We

Yifan Chen; Jianqi Teo; Joshua C. Y. Lai; Erry Gunawan; Kay Soon Low; Cheong Boon Soh; Predrag B. Rapajic

2009-01-01

3

Ultra-Wideband Technology for Short or Medium-Range Wireless Communications  

Microsoft Academic Search

Ultra-Wideband (UWB) technology is loosely defined as any wireless transmission scheme that occupies a bandwidth of more than 25% of a center frequency, or more than 1.5GHz. The Federal Communications Commission (FCC) is currently working on setting emissions limits that would allow UWB communication systems to be deployed on an unlicensed basis following the Part 15.209 rules for radiated emissions

Jeff Foerster; Evan Green; Srinivasa Somayazulu; David Leeper

2001-01-01

4

Self Organization of Wireless Sensor Networks Using Ultra-Wideband Radios  

SciTech Connect

Ultra-wideband (UWB) technology has proven to be useful in short range, high data rate, robust, and low power communications. These features can make UWB systems ideal candidates for reliable data communications between nodes of a wireless sensor network (WSN). However, the low powered UWB pulses can be significantly degraded by channel noise, inter-node interference, and intentional jamming. In this paper we present a novel interference suppression technique for UWB based WSNs that promises self-organization in terms of power conservation, scalability, and channel estimation for the entire distributed network.

Nekoogar, F; Dowla, F; Spiridon, A

2004-07-19

5

An ultra wideband propagation model for wireless cardiac monitoring devices  

Microsoft Academic Search

Wireless communication is an important technology to improve e-health applications such as remote cardiac monitoring. In modern telemedicine it is desirable that implant cardiac devices such as pacemakers can be interrogated and reprogrammed remotely. Such functions require a reliable wireless communication channel between the implant device and an external control unit. In order to increase the longevity of the implant

Raúl Chávez-Santiago; Ali Khaleghi; Ilangko Balasingham

2010-01-01

6

Dispersion Limitations of Ultra-Wideband Wireless Links and Their Compensation Via Photonically Enabled Arbitrary Waveform Generation  

Microsoft Academic Search

In this study, we present compression of ultra-wideband RF waveforms via photonic synthesis of phase pre-compensated waveforms. By exciting a dispersive wireless link (employing Archimedean spiral antennas) with variable-bandwidth excitation waveforms, we first demonstrate that such links exhibit a dispersion-limited output pulse duration. Subsequently, we utilize the RF spectral phase extracted from the impulse response of the link to create

Jason D. McKinney; Dimitrios Peroulis; Andrew M. Weiner

2008-01-01

7

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

8

Ultra-wideband radar sensors and networks  

DOEpatents

Ultra wideband radar motion sensors strategically placed in an area of interest communicate with a wireless ad hoc network to provide remote area surveillance. Swept range impulse radar and a heart and respiration monitor combined with the motion sensor further improves discrimination.

Leach, Jr., Richard R; Nekoogar, Faranak; Haugen, Peter C

2013-08-06

9

Ultra-wideband receiver  

DOEpatents

An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, .+-.UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

10

Ultra-wideband receiver  

DOEpatents

An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, .+-.UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals.

McEwan, Thomas E. (Livermore, CA)

1994-01-01

11

Ultra-wideband receiver  

DOEpatents

An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, [+-] UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals. 16 figs.

McEwan, T.E.

1994-09-06

12

Ultra-wideband receiver  

DOEpatents

An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, {+-}UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals. 21 figs.

McEwan, T.E.

1996-06-04

13

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

14

Single-element based ultra-wideband antenna array concepts for wireless high-precision 2-D local positioning  

NASA Astrophysics Data System (ADS)

We generally categorize the approaches for ultra-wideband antenna array design, and consequently propose simplified concepts for antenna arrays for a high-precision, ultra-wideband FMCW radar 2-D local positioning system to obtain robustness against multi path interference, perform angle of arrival analysis, as well as instantaneous heading estimation. We focus on low-cost and mechanical robust, industrial-application ready antennas. The antenna arrays are optimized for operation in the 5 GHz to 8 GHz frequency range and are designed towards supporting full omnidirectional 360° as well as partial half-plane direction of arrival estimation. Two different concepts for vehicle- as well as wall-mounted antenna array systems are proposed and discussed. We propose a wideband unidirectional bow-tie antenna array element having 97% impedance and 37% pattern bandwidth and a robust vehicle mounted omnidirectional antenna element having more than 85% impedance and pattern bandwidth.

Gardill, M.; Fischer, G.; Weigel, R.; Koelpin, A.

2013-07-01

15

On ultra wideband channel modeling for in-body communications  

Microsoft Academic Search

Innovative medical applications such as implant wireless sensors for health monitoring, automatic drug deliverance, etc. can be realized with the use of ultra wideband (UWB) radio technology. Nevertheless, for efficient design of wireless systems operating inside the human body a radio communication channel model is essential. Although a lot of research effort has recently been devoted to the characterization of

A. Khaleghi; R. Chavez-Santiago; X. Liang; I. Balasingham; V. C. M. Leung; T. A. Ramstad

2010-01-01

16

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

17

Ultra-wideband transmitter research  

Microsoft Academic Search

The generation of ultra-wideband (UWB) pulses is a challenging problem that involves generating pulses with fast rise times on the order of 100 ps and voltages of more than 500 kV. Pulsewidths from 130 ps to a few nanoseconds (ns) are possible. A critical step involves switching high voltages with precision. The use of both gas and oil for the

Forrest J. Agee; Carl E. Baum; William D. Prather; Jane M. Lehr; J. P. O'Loughlin; J. W. Burger; J. S. H. Schoenberg; D. W. Scholfield; R. J. Torres; J. P. Hull; J. A. Gaudet

1998-01-01

18

Ultra-wideband source research  

Microsoft Academic Search

Ultra-wideband (UWB) microwave sources and antennas are of interest for a variety of applications such as transient radar, mine detection and unexploded ordnance (UXO) location and identification. Much of the current research is being performed at the Air Force Research Laboratory (AFRL) at Kirtland AFB, NM, USA. The approach to high power source development has included high pressure gas switching,

William D. Prather; Carl E. Baum; Jane M. Lehr; J. P. O'Loughlin; S. Tyo; J. S. H. Schoenberg; R. J. Torres; T. C. Tran; D. W. Scholfield; J. W. Burger; J. Gaudet

1999-01-01

19

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

20

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

21

Ultra-Wideband channel model for intra-vehicular wireless sensor networks  

Microsoft Academic Search

Intra-vehicular wireless sensor networks is a promising new research area that can provide part cost, assembly, maintenance savings and fuel efficiency through the elimination of the wires, and enable new sensor technologies to be integrated into vehicles, which would otherwise be impossible using wired means, such as Intelligent Tire. The most suitable technology that can meet high reliability, strict energy

C. Umit Bas; Sinem Coleri Ergen

2012-01-01

22

Impulse radio ultra-wideband DC power modeling  

Microsoft Academic Search

Several IEEE standards for modern Wireless Sensor Network (WSN) radios make use of impulse radio ultra-wideband (IR-UWB). To keep power consumption to a minimum, pulses are grouped together in bursts. This paper presents a model used to analyze the relationship between DC power consumption, burst length and link budget for both peak and average power limited systems. Such a model

Hans W. Pflug; Jac Romme; Kathleen Philips; Harmke de Groot

2011-01-01

23

Low data rate ultra wideband ECG monitoring system.  

PubMed

This paper presents a successfully implemented wireless electrocardiograph monitoring using low data rate ultra wideband (UWB) transmission. Low data rate ultra wideband is currently under consideration for the newly formed wireless body area network (WBAN) group (IEEE802.15.6) to develop a standard for wireless vital sign monitoring. Maximizing the transmission power of the transmitter and reducing the stringent requirements and complexity of the receiver have always been the key considerations for an UWB transceiver. Multiple pulses per bit has been sent in our low data rate UWB prototype system to increase the transmitter power, to reduce the complexity of the receiver and to ease the requirement on the receiver's analog to digital converter. Non-coherent technique has been used for the demodulation of UWB signals at the receiver that reduces the receiver complexity further. PMID:19163442

Keong, Ho Chee; Yuce, Mehmet R

2008-01-01

24

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

25

A platform for ultra wideband communication systems  

E-print Network

In this thesis, a web interface for sending and receiving data across an actual UWB channel was designed. In addition, a platform for Ultra Wideband (UWB) communication development was implemented. The UWB communication ...

Ackerman, Nathan (Nathan Joseph)

2005-01-01

26

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

27

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

28

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

29

Prototype ultra wideband-based wireless body area network--consideration of CAP and CFP slot allocation during human walking motion.  

PubMed

This paper presents an experimental evaluation of communication during human walking motion, using the medium access control (MAC) evaluation system for a prototype ultra-wideband (UWB) based wireless body area network for suitable MAC parameter settings for data transmission. Its physical layer and MAC specifications are based on the draft standard in IEEE802.15.6. This paper studies the effects of the number of retransmissions and the number of commands of GTS (guaranteed time slot) request packets in the CAP (contention access period) during human walking motion by varying the number of sensor nodes or the number of CFP (contention free period) slots in the superframe. The experiments were performed in an anechoic chamber. The number of packets received is decreased by packet loss caused by human walking motion in the case where 2 slots are set for CFP, regardless of the number of nodes, and this materially decreases the total number of packets received. The number of retransmissions and the GTS request commands increase according to increases in the number of nodes, largely reflecting the effects of the number of CFP slots in the case where 4 nodes are attached. In the cases where 2 or 3 nodes are attached and 4 slots are set for CFP, the packet transmission rate is more than 95%. In the case where 4 nodes are attached and 6 slots are set for CFP, the packet transmission rate is reduced to 88% at best. PMID:23366429

Takei, Yuichiro; Katsuta, Hiroki; Takizawa, Kenichi; Ikegami, Tetsushi; Hamaguchi, Kiyoshi

2012-01-01

30

Ultra-wideband source and antenna research  

Microsoft Academic Search

Ultra-wideband (UWB) microwave sources and antennas are of interest for a variety of applications, such as transient radar, mine detection, and unexploded ordnance (UXO) location and identification. Much of the current research is being performed at the Air Force Research Laboratory (AFRL) at Kirtland AFB, NM. The approach to high power source development has included high pressure gas switching, oil

William D. Prather; Carl E. Baum; Jane M. Lehr; J. P. O'Loughlin; S. Tyo; J. S. H. Schoenberg; R. J. Torres; T. C. Tran; D. W. Scholfield; J. Gaudet; J. W. Burger

2000-01-01

31

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

32

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

33

Hardware channel model for ultra wideband systems  

Microsoft Academic Search

We present a digital hardware model for ultra wideband channels. The system runs at 80 MHz on a Xilinx Virtex-4 xc4vsx35 FPGA. High-speed arithmetic operations including division, square root, powering and normal random number generator are analyzed and developed for use as basic components in the channel emulator. The design flow is based on Matlab Simulink as the model builder,

Wen-Chih Kan; Gerald E. Sobelman

2006-01-01

34

Compact ultra-wideband metamaterial antenna  

Microsoft Academic Search

A negative index metamaterial antenna is presented in this paper for ultra-wideband (UWB) applications; which operates in C and X-bands. The proposed antenna is composed of three-unit cells of left-handed metamaterial (LHM) where these LHM unit cells are composed of a combination of modified octagonal spiral resonator (OSR), octagonal split-ring resonator (OSRR), capacitance-loaded strip (CLS), and wire that exhibit negative

A. R. H. Alhawari; A. Ismail; M. A. Mahdi

2010-01-01

35

Ray-tracing based modeling of ultra-wideband pulse propagation in railway tunnels  

Microsoft Academic Search

Ray tracing based on geometric optics can be utilized for generating propagation models for arbitrary and com- plex environments. These methods can be employed to determine important wireless channel characteristics such as coherence and delay spread. In this paper, an image theory based ray tracing method is used to study ultra-wideband propagation in complex tunnel environments such as curved tunnels

Neeraj Sood; Liang Liang; Sean V. Hum; Costas D. Sarris

2011-01-01

36

An Emission Strategy of Cognitive Radio-Ultra Wideband Based on Interference Temperature Model  

Microsoft Academic Search

The cognitive radio combining ultra wideband (CRUWB) system will be considered as one of the candidates of the next generation short range wireless communication technology. For no any idle frequency band in the current radio environment, the emission power of CR-UWB must regulate to assure that the licensed users work normally. In this paper, based on the interference temperature model,

Shubin Wang; Zheng Zhou; Kyungsup Kwak

2009-01-01

37

Ultra-wideband channel model for communication around the human body  

Microsoft Academic Search

Using ultra-wideband (UWB) wireless sensors placed on a person to continuously monitor health information is a promising new application. However, there are currently no detailed models describing the UWB radio channel around the human body making it difficult to design a suitable communication system. To address this problem, we have measured radio propagation around the body in a typical indoor

Andrew Fort; Julien Ryckaert; Claude Desset; Philippe De Doncker; Piet Wambacq; Leo Van Biesen

2006-01-01

38

Ultra Wideband Indoor Radio Channel Models: Preliminary Results  

Microsoft Academic Search

ULTRA WIDEBAND RADIO CHAN-NEL MEASUREMENT TECHNIQUES Knowledge of the signal propagation mechanisms in the chan-nel is vital for the radio system design and the system perform-ance analysis. However, currently published wideband or nar-rowband radio channel models do not offer spatial resolution high enough for the ultra wideband (UWB) applications and the real channel measurements are needed. In this paper is

Veikko Hovinen

2002-01-01

39

Polarization diverse ultra-wideband antenna technology  

NASA Astrophysics Data System (ADS)

This paper presents an ultra-wideband (UWB) antenna design that is capable of multiple polarizations. The multiple element design provides polarization diversity while maintaining desirable phase and standing wave characteristics. The prospect of replacing multiple single purpose antennas on a modern military platform with a single antenna capable of wideband and multi-function operation is of significant interest. Considering space availability, maintenance simplification and aerodynamics, antenna count is now carefully considered in the planning of each new aircraft and space vehicle and in many modification of existing equipment. The broadband radiation capability of this antenna together with its polarization and phase characteristics suggest the possibility of its service in such applications. This antenna can also be of use in other environments such as satellite communications for both the orbital vehicle and the earthbound receptor functions. In the latter, the earthbound satellite receptor use of this antenna can be supplemented with a parabolic dish or other reflector arrangement.

Wicks, Michael C.; Antonik, Paul

1993-01-01

40

A PPM GAUSSIAN PULSE GENERATOR FOR ULTRA-WIDEBAND COMMUNICATIONS  

E-print Network

A PPM GAUSSIAN PULSE GENERATOR FOR ULTRA-WIDEBAND COMMUNICATIONS Sumit Bagga1 , Giuseppe de Vita2, Pisa, Italy Email: gi.devita@tiscali.it ABSTRACT A Gaussian pulse generator incorporating a pulse position modulator for use in an ultra-wideband or impulse radio system is described. The pulse generator

Serdijn, Wouter A.

41

Ultra-Wideband Imaging Systems for Breast Cancer Detection  

E-print Network

Ultra-Wideband Imaging Systems for Breast Cancer Detection Hossein Kassiri Bidhendi, Hamed Mazhab system design and its advantages for breast cancer detection after reading this chapter. Keywords Breast cancer detection · Breast imaging · Ultra-wideband imaging · UWB transceiver · UWB pulses · UWB

Genov, Roman

42

Ultra Wideband (UWB) communication vulnerability for security applications.  

SciTech Connect

RF toxicity and Information Warfare (IW) are becoming omnipresent posing threats to the protection of nuclear assets, and within theatres of hostility or combat where tactical operation of wireless communication without detection and interception is important and sometimes critical for survival. As a result, a requirement for deployment of many security systems is a highly secure wireless technology manifesting stealth or covert operation suitable for either permanent or tactical deployment where operation without detection or interruption is important The possible use of ultra wideband (UWB) spectrum technology as an alternative physical medium for wireless network communication offers many advantages over conventional narrowband and spread spectrum wireless communication. UWB also known as fast-frequency chirp is nonsinusoidal and sends information directly by transmitting sub-nanosecond pulses without the use of mixing baseband information upon a sinusoidal carrier. Thus UWB sends information using radar-like impulses by spreading its energy thinly over a vast spectrum and can operate at extremely low-power transmission within the noise floor where other forms of RF find it difficult or impossible to operate. As a result UWB offers low probability of detection (LPD), low probability of interception (LPI) as well as anti-jamming (AJ) properties in signal space. This paper analyzes and compares the vulnerability of UWB to narrowband and spread spectrum wireless network communication.

Cooley, H. Timothy

2010-07-01

43

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

44

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

45

Ultra wideband indoor radio channel models: preliminary results  

Microsoft Academic Search

Knowledge of the signal propagation mechanisms in the channel is vital for the radio system design and the system performance analysis. However, currently published wideband or narrowband radio channel models do not offer spatial resolution high enough for the ultra wideband (UWB) applications and real channel measurements are needed. The preliminary UWB radio channel model for a selected radio link-configuration

V. Hovinen; Matti Hamalainen; Tinzo Patsi

2002-01-01

46

Ultra Wideband Indoor Radio Channel Models: Preliminary Results  

Microsoft Academic Search

Knowledge of the signal propagation mechanisms in the chan- nel is vital for the radio system design and the system perform- ance analysis. However, currently published wideband or nar- rowband radio channel models do not offer spatial resolution high enough for the ultra wideband (UWB) applications and the real channel measurements are needed. In this paper is given the preliminary

Veikko Hovinen; Matti Hämäläinen; Timo Pätsi

47

An Ultra Wideband Aperture Coupled Bowtie Antenna for Communications  

NASA Astrophysics Data System (ADS)

The application of ultra wideband communications lies mainly in the networking of portable devices like camcorders, digital cameras and personal digital assistants (PDA). This constitutes the need for small ultra-wideband antennas that can be integrated into such devices. With this motivation an investigation of the new aperture coupled bowtie antenna concept is presented together with design rules and measurement results of the frequency domain and time domain characteristics.

Sörgel, W.; Waldschmidt, C.; Wiesbeck, W.

48

An Investigation of Bluetooth Mergence with Ultra Wideband  

Microsoft Academic Search

This paper presents an investigation into some merging options between an upper-layer Bluetooth (BT) protocol stack with a lower-layer ECMA-368\\/9 ultra wideband (UWB) radio connection. A Bluetooth over ultra wideband (BToUWB) system is modeled by channeling an existing compliant Bluetooth connection's data over a software implemented UWB medium access control (MAC) and simulated physical (PHY) layer radio channel. The aim

Etienne Van Der Linde; Gerhard P. Hancke

2008-01-01

49

An ultra wideband communication channel model for the human abdominal region  

Microsoft Academic Search

Long-term implantable devices communicating with receivers in the outer human body through a wireless interface are one of the most prominent applications of micro\\/nano-technology in medicine. Ultra wideband (UWB) interfaces have great potential for the communication links of these telemedicine applications due to their inherent low power consumption, high transmission rates, and simple electronics. Novel implant medical sensors and actuators

Stig Støa; Raul Chavez-Santiago; Ilangko Balasingham

2010-01-01

50

A novel approach for Ultra-wideband MIMO channel modeling  

Microsoft Academic Search

Channel models used for analysis of narrowband systems are inadequate for Ultra-wideband (UWB) systems. In addition, the combination of UWB signals with multiple-input multiple-output (MIMO) technology increase the necessity of developing new channel models appropriate for wideband transmissions. In this paper we determine a new channel transfer function (CTF) for UWB channels and using this expression we calculate the space-time-frequency

Ana-Maria Pistea; Tudor Palade; Anca Moldovan

2010-01-01

51

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

52

Data gathering in ultra wide band based wireless sensor networks using a mobile node  

Microsoft Academic Search

Ultra-wideband (UWB) communications is receiving significant attention recently due to its high data rates and low power, low interference transmission. This paper considers the issue of utilizing these advantages of UWB to design improved Wireless Sensor Networks (WSNs). In particular, we consider data gathering in wireless sensor networks using a mobile node for data collection. We first propose a network

Deepak Bote; Krishna M. Sivalingam; Prathima Agrawal

2007-01-01

53

Modeling of ultra wideband transmission through building walls  

Microsoft Academic Search

The prediction of transmission phenomenon through the building walls is one of the fundamental parts of the ultra wideband (UWB) channel modeling in the indoor propagation environments. Considering the broad variety of the wall materials and the equivalent electric parameters, the need to an accurate method for modeling UWB signal transmission is increased. The objective of this work is to

Narges Noori; Ali Abolghasemi; Masoum Fardis

2008-01-01

54

Ultra wideband radar for water detection in the human body  

Microsoft Academic Search

In this paper an Impulse Radio Ultra Wideband (IRUWB) radar for detecting water accumulation in the human body is proposed. The method of On-body water detection is investigated both in a simulator with a bladder model and measurement system with a phantom. The Vivaldi antenna is used in the measurement system. The simulation and measurement results show the feasibility of

Xuyang Li; Elena Pancera; Lukasz Zwirello; Huaming Wu; Thomas Zwick

2010-01-01

55

A Maximum Entropy Approach to Ultra-Wideband Channel Modeling  

Microsoft Academic Search

In this paper, a unified framework for ultra-wideband channel (UWB channel) modeling based on the maximum entropy approach is provided. For a given set of constraints, a consistent model which takes into account the information at hand is obtained. Two cases are considered: channel power knowledge and knowledge of the covariance matrix. The channel power delay spectrum is also derived

R. L. de Lacerda Neto; A. Menouni; M. Debbah; B. H. Fleury

2006-01-01

56

An Empirical Ultra Wideband Channel Model for Indoor Laboratory Environments  

Microsoft Academic Search

Channel measurement and modeling is an im- portant issue when designing ultra wideband (UWB) com- munication systems. In this paper, the results of some UWB time-domain propagation measurements performed in modern laboratory (Lab) environments are presented. The Labs are equipped with many electronic and measurement devices which make them different from other indoor loca- tions like office and residential environments.

Narges NOORI; Roghieh KARIMZADEH-BAEE; Ali ABOLGHASEMI

57

Ultra-wideband (UWB) communication link modeling and characterization  

Microsoft Academic Search

This paper introduces modeling of a ultra-wideband (UWB) communication link, using two monopole antennas, in terms of the singularity expansion method (SEM) via Prony's method. Prony's Method is used to extract poles and residues of the link. By obtaining the poles and residues of the link it is possible to construct a transfer function of the link in both time

Stanislav Licul; William A. Davis; Warren L. Stutzman

2003-01-01

58

Ultra-wideband EM modeling using DCI-PEEC method  

Microsoft Academic Search

This paper presents the DCI-PEEC method in the application of electromagnetic simulation. The exact full-wave Green's function for multi-layered media from discrete complex image (DCI) makes partial element equivalent circuit (PEEC) method available for the ultra-wideband modeling. An example of S parameter calculation for on-chip spiral inductor verifies this method.

Zhi-Yuan Zong; Wen Wu; Da-Gang Fang

2010-01-01

59

Recent Progress in Ultra-Wideband Microwave Breast Cancer Detection  

E-print Network

Recent Progress in Ultra-Wideband Microwave Breast Cancer Detection Simone A. Winkler, Emily Porter in the field of breast cancer detection research carried out at McGill University. A low-cost time performance. Latest results are shown and presented in comparison to prior experiments. Keywords-breast cancer

Coates, Mark

60

Novel approach to ultra-wideband antenna design  

Microsoft Academic Search

A novel approach to ultra-wideband (UWB) antenna design is presented which is based on a general description for the geometry of monopole antennas. This general description is capable of producing almost all possible shapes for monopole antennas and it is compatible with different optimization methods. The general description is used for the optimization of rotationally-symmetric monopole antenna with finite ground

K. Paran; M. Fardis; A. Abolghasemi

2008-01-01

61

Ultra-wideband Radar Data Models and Target Detection with Adaptive Rank-Order Filters  

Microsoft Academic Search

ABSTRACT A number,of aspects of ultra-wideband radar target detection analysis and algorithm development,are addressed. The first portion of the paper describes a bi-modal technique for modeling ultra-wideband radar clutter. This technique was developed based on an analysis of ultra-wideband radar phenomenology.,Synthetic image,samples,that were generated by this modeling,process are presented. This sample set is characterized by a number,of physical parameters. The

Patterson Afb; Atindra K. Mitra; Thomas L. Lewis; Anindya S. Paul; Arnab K. Shaw

62

Design and Simulation of Ultra-wideband Quad-Ridged Horn Antenna  

Microsoft Academic Search

An ultra-wideband quad-ridged horn antenna in ultra-wideband communication system is described in which offer unique advantages its own structure characters. By simulation and optimization, the 2-18 GHz quad-ridged horn antenna can realize high gain and dual polarization operations, and the operating bandwidth is enough for practical operation. The simulation results and analyses of the ultra-wideband quad-ridged horn antenna are presented.

Jinghui Qiu; Ying Suo; Wei Li

2007-01-01

63

TO APPEAR IN IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS (SPECIAL ISSUE ON ULTRA WIDEBAND WIRELESS COMMUNICATIONS) 1 Secure Localization and Authentication in  

E-print Network

of unique merits such as low probability of interception and detection, resilience to multi-path fading, it is finding ever-increasing uses in wireless communications, networking, radar imaging, and localization and often hostile settings such as tactical military operations and homeland security monitoring. Under

Wu, Dapeng Oliver

64

A novel DHT-based ultra-wideband system  

Microsoft Academic Search

In this paper, a low complexity orthogonal frequency division multiplexing (OFDM) system is proposed for use in high-speed ultra-wideband physical links. Discrete Hartley transform (DHT) and its inverse are employed to perform modulation\\/demodulation. A data-aided channel estimation algorithm is derived. Both the computational complexity and hardware cost of this system are much lower than that of conventional DFT-based OFDM. The

Deqiang Wang; Danpu Liu; Fang Liu; Guangxin Yue

2005-01-01

65

Simulation of indoor ultra wideband propagation channel modeling  

Microsoft Academic Search

UWB (ultra wideband) propagation channel modeling is very important for UWB communication system designing and its performance optimization. The split-field PML (perfectly matched layer) and unsplit-field PML were combined respectively with PSTD (pseudospectral time-domain) method to model 2-D (two dimensional) and 3-D indoor UWB propagation. The attenuation factor algorithm was applied to simulate realistic UWB propagation under 2-D environment. Channel

Huaibei Zhou; Chunhua Yang; Fan Wang

2005-01-01

66

Ultra-wideband outdoor channel modeling using ray tracing techniques  

Microsoft Academic Search

An ultra-wideband (UWB) channel modeling approach using ray tracing techniques is presented. The scenario consists of a farm area with clusters of scatterers over moderately varying terrain. The channel sounding consists of power-scaled distinct frequencies whereby all relevant ray signal descriptors are captured. From this we develop a two-ray and three-ray path loss model with associated parameters. The technique is

Shahriar Emami; Celestino A. Corral; Gregg Rasor

2005-01-01

67

Ultra wideband antenna design for implant applications  

Microsoft Academic Search

Wireless telemetry based secure communication has been extensively worked to improve the life quality of patients having heart problems, diabetic problems and so on. Information of appropriate biosensors could be transferred via implant antennas to which, there are a growing research interests. In the scope of this work, we have designed a wide band antenna for biotelemetry communication. Radiation diagram,

F. Zengin; B. Turetken; E. Akkaya; S. E. San

2010-01-01

68

A deterministic ultra wideband channel modeling  

Microsoft Academic Search

We study the realisation of a deterministic channel modeling which allows the construction of a realistic received waveform from a wireless spread spectrum multiple-access (SSMA) using time hopping (TH) modulation. The goal is to reach the symbol decision from a simulated waveform. This paper explains how to use the uniform theory of diffraction (UTD) method combined with a ray tracing

Bernard Uguen; Eric Plouhinec; Yves Lostanlen; G. Chassay

2002-01-01

69

Wideband channel measurement and characterisation for wireless local loops  

Microsoft Academic Search

The multipath characteristics of the wireless local loop (WLL) channel were studied over both short and long time periods in urban and sub-urban high-rise and small-house environments. Wideband measurements were performed at a centre frequency of 1.3 GHz with a sliding correlation measurement system using a chip rate of 15 MHz. The receiver was situated at regular cellular base stations,

Jaakko Talvitie; Veikko Hovinen; Matti Hamaliiinen; Ian Oppermann

1996-01-01

70

Design Of Ultra Wideband Coplanar Waveguide Fed Rectangular Slot Antenna With Tuning Stub  

E-print Network

Design Of Ultra Wideband Coplanar Waveguide Fed Rectangular Slot Antenna With Tuning Stub antenna tuned by a patch stub is designed and presented for ultra wideband band applications simulation and analysis for this class of antennas are performed using the Momentum software package

Elsherbeni, Atef Z.

71

Ultra-wideband microwave photonic phase shifter with a 360 tunable phase shift based  

E-print Network

Ultra-wideband microwave photonic phase shifter with a 360° tunable phase shift based on an erbium-ytterbium photonic approach to implementing an ultra-wideband microwave phase shifter based on an erbium­ ytterbium-light effects in a semiconductor optical amplifier (SOA) [9] or in a tilted fiber Bragg gra- ting [10

Yao, Jianping

72

A New Medium Access Control Protocol for TDD Mode Wideband CDMA Wireless Local Area Networks  

Microsoft Academic Search

It is well known that TDD mode wideband CDMA is particularly suited for wireless local area networks (LANs). In this paper a medium access control (MAC) protocol is proposed for wireless multimedia LANs that are based on TDD mode wideband CDMA. In order to minimize interference experienced by a packet and to satisfy bit error rates (BERs) of multimedia traffic,

Ian F. Akyildiz; Xudong Wang

73

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

74

A concept for hip prosthesis identification using ultra wideband radar.  

PubMed

Ultra wideband (UWB) radar has been extensively investigated both theoretically and practically for the identification buried artifacts. Ground probe radar (GPR) concentrates on the identification of lightly buried land mines, unexploded ordnance (UXO) and archeological targets. The same technology is proposed in a similar context for the rapid identification of in vivo implanted metallic prostheses. The technique is based on resonance based target identification and the paper investigates UWB scattering from a metallic hip prosthesis in free space as a first step in the identification process. PMID:17271965

Lui, Hoi-Shun; Shuley, Nicholas; Crozier, Stuart

2004-01-01

75

Optically addressed ultra-wideband phased antenna array  

NASA Astrophysics Data System (ADS)

Demands for high data rate and multifunctional apertures from both civilian and military users have motivated development of ultra-wideband (UWB) electrically steered phased arrays. Meanwhile, the need for large contiguous frequency is pushing operation of radio systems into the millimeter-wave (mm-wave) range. Therefore, modern radio systems require UWB performance from VHF to mm-wave. However, traditional electronic systems suffer many challenges that make achieving these requirements difficult. Several examples includes: voltage controlled oscillators (VCO) cannot provide a tunable range of several octaves, distribution of wideband local oscillator signals undergo high loss and dispersion through RF transmission lines, and antennas have very limited bandwidth or bulky sizes. Recently, RF photonics technology has drawn considerable attention because of its advantages over traditional systems, with the capability of offering extreme power efficiency, information capacity, frequency agility, and spatial beam diversity. A hybrid RF photonic communication system utilizing optical links and an RF transducer at the antenna potentially provides ultra-wideband data transmission, i.e., over 100 GHz. A successful implementation of such an optically addressed phased array requires addressing several key challenges. Photonic generation of an RF source with over a seven-octave bandwidth has been demonstrated in the last few years. However, one challenge which still remains is how to convey phased optical signals to downconversion modules and antennas. Therefore, a feed network with phase sweeping capability and low excessive phase noise needs to be developed. Another key challenge is to develop an ultra-wideband array antenna. Modern frontends require antennas to be compact, planar, and low-profile in addition to possessing broad bandwidth, conforming to stringent space, weight, cost, and power constraints. To address these issues, I will study broadband and miniaturization techniques for both single and array antennas. In addition, a prototype transmitting phased array system is developed and shown to demonstrate large bandwidth as well as a beam steering capability. The architecture of this system can be further developed to a large-scale array at higher frequencies such as mm-wave. This solution serves as a candidate for UWB multifunctional frontends.

Bai, Jian

76

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

77

A compact ultra wideband antenna with WiMax band rejection for energy scavenging  

NASA Astrophysics Data System (ADS)

Radio Frequency (RF) energy harvesting has been rapidly advancing as a promising alternative to existing energy scavenging system. A well designed broadband antenna such as ultra-wideband (UWB) antenna can be used as one of the major components in an RF energy scavenging system. This paper presents a compact UWB antenna showing good impedance matching over a bandwidth of 2.8 to 11 GHz, suiTable for broadband RF energy scavenging. Nevertheless, the antenna usage in wireless communication has a limitation due to the problem of interference between UWB system and other narrowband systems. Thus, the proposed antenna is successfully designed with a single band-notched at the targeted WiMAX operating band of 3.3 to 3.6 GHz.

Jalil, Y. E.; Kasi, B.; Chakrabarty, C. K.

2013-06-01

78

Emerging Communication Technologies (ECT) Phase 2 Report. Volume 3; Ultra Wideband (UWB) Technology  

NASA Technical Reports Server (NTRS)

The Emerging Communication Technology (ECT) project investigated three First Mile communication technologies in support of NASA s Second Generation Reusable Launch Vehicle (2nd Gen RLV), Orbital Space Plane, Advanced Range Technology Working Group (ARTWG) and the Advanced Spaceport Technology Working Group (ASTWG). These First Mile technologies have the purpose of interconnecting mobile users with existing Range Communication infrastructures. ECT was a continuation of the Range Information System Management (RISM) task started in 2002. RISM identified the three advance communication technologies investigated under ECT. These were Wireless Ethernet (Wi-Fi), Free Space Optics (FSO), and Ultra Wideband (UWB). Due to the report s size, it has been broken into three volumes: 1) Main Report 2) Appendices 3) UWB

Bastin, Gary L.; Harris, William G.; Chiodini, Robert; Nelson, Richard A.; Huang, PoTien; Kruhm, David A.

2003-01-01

79

Multicarrier CDMA techniques for future wideband wireless networks  

Microsoft Academic Search

\\u000a Abstract  In this paper, multicarrier techniques are considered in the context of the future wideband wireless networks. An overview\\u000a of the different access schemes based on a combination of code division and multicarrier techniques, such as Multi-Carrier\\u000a Code Division Multiple Access (MC-CDMA), Multi-Carrier Direct Sequence CDMA (MC-DS-CDMA) and Multi-Tone CDMA (MT-CDMA) is\\u000a presented first. Afterwards, MC-CDMA systems are considered for the

Maryline Hélard; Rodolphe Le Gouable; Jean-Francois Hélard; Jean-Yves Baudais

2001-01-01

80

Inkjet Printed Ultra Wideband Spiral Antenna Using Integrated Balun on Liquid Crystal Polymer (LCP)  

E-print Network

Inkjet Printed Ultra Wideband Spiral Antenna Using Integrated Balun on Liquid Crystal Polymer (LCP, integrated balun is inkjet printed on liquid crystal polymer (LCP) substrate and operates successfully from 1 and the spiral arms are inkjet printed on LCP. The fabricated antenna covers a wideband frequency range (1~8GHz

Tentzeris, Manos

81

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

82

Microwave (De) Multiplexer for Ultra-Wideband (UWB) Non-Coherent High Data Rates Transceiver  

Microsoft Academic Search

The following topics are dealt with: low-loss planar multiplexer\\/demultiplexers; ultra-wideband high data rate (UWB HDR) transceivers; impulse radio; microstrip passive quadriplexers; 2nd order filters and open-loop resonators

Stéphane Mallégol; Jean-Philippe Coupez; Christian Person; Thomas Lespagnol; Stéphane Paquelet; Alexis Bisiaux

2006-01-01

83

Ultra-wideband Radar Methods and Techniques of Medical Sensing and Imaging  

SciTech Connect

Ultra-wideband radar holds great promise for a variety of medical applications. We have demonstrated the feasibility of using ultra-wideband sensors for detection of internal injuries, monitoring of respiratory and cardiac functions, and continuous non-contact imaging of the human body. Sensors are low-power, portable, and do not require physical contact with the patient. They are ideal for use by emergency responders to make rapid diagnosis and triage decisions. In the hospital, vital signs monitoring and imaging application could improve patient outcomes. In this paper we present an overview of ultra-wideband radar technology, discuss key design tradeoffs, and give examples of ongoing research in applying ultra-wideband technology to the medical field.

Paulson, C N; Chang, J T; Romero, C E; Watson, J; Pearce, F J; Levin, N

2005-10-07

84

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

85

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

86

Ultra-wideband horn antenna with abrupt radiator  

DOEpatents

An ultra-wideband horn antenna transmits and receives impulse waveforms for short-range radars and impulse time-of flight systems. The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna. Dispersion is minimized with an abrupt launch point radiator element; sidelobe and feedline coupling are minimized by recessing the radiator into a metallic horn. Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies. A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn. The launcher plate and feed plate join at an abrupt edge which forms the single launch point of the antenna. 8 figs.

McEwan, T.E.

1998-05-19

87

Ultra-wideband horn antenna with abrupt radiator  

DOEpatents

An ultra-wideband horn antenna transmits and receives impulse waveforms for short-range radars and impulse time-of flight systems. The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna. Dispersion is minimized with an abrupt launch point radiator element; sidelobe and feedline coupling are minimized by recessing the radiator into a metallic horn. Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies. A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn. The launcher plate and feed plate join at an abrupt edge which forms the single launch point of the antenna.

McEwan, Thomas E. (Livermore, CA)

1998-01-01

88

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

89

Bandwidth extension for ultra-wideband CMOS low-noise amplifiers  

Microsoft Academic Search

Techniques are proposed to enhance the bandwidth of ultra-wideband (UWB) CMOS low-noise amplifiers (LNA). By using multiple-input-branch technique and resistive shunt- feedback technique, LNA could achieve ultra-wideband input impedance matching with small noise figure degradation. The gain bandwidth is enhanced by an L type inter-stage matching network between the input transistors and the cascode transistor which could enhance both the

Baoyong Chi; Chun Zhang; Zhihua Wang

2008-01-01

90

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

91

Ultra-wideband Propagation Loss Around a Human Body in Various Surrounding Environments  

NASA Astrophysics Data System (ADS)

Ultra-wideband (UWB) technologies have been anticipated for use in wireless body area networks (WBAN) because of their low power consumption and anti-multipath capabilities. This chapter presents the UWB (3.1-10.6 GHz) propagation loss in WBAN scenarios between on-body antennas in three different surrounding environments. The measurements were performed in a 3-m radio anechoic chamber, a classroom, and a small room. The propagation paths were roughly divided into line-of-sight (LOS) and non-LOS (NLOS) ones. Small rooms, particularly NLOS, yielded higher reception power than larger rooms. This was attributed to the ample multipath from the nearby floor, walls, and ceiling. The UWB maximum propagation losses in three surrounding environments were smaller than ones of CW (6.85 GHz). This is because nulls caused by interference were cancelled out by the ultra-wide bandwidth. The propagation losses of low-band (3.4-4.8 GHz) and high-band (7.25-10.25 GHz) UWB were also evaluated. In WBAN scenarios, the low-band yielded lower propagation loss than the high-band and approximately the same loss as the full-band UWB (3.1-10.6 GHz).

Yamamoto, H.; Kobayashi, T.

92

Ultra-wideband VHF SAR -- Design and measurements  

SciTech Connect

CARABAS, an acronym for ``Coherent All Radio Band Sensing``, is an airborne, horizontal-polarization SAR operating across the frequency band 20--90 MHz, conceived, designed and built by FOA in Sweden. The original motivation for designing such a low frequency system was that a large relative or fractional bandwidth could be achieved at low frequencies. For reasons to be explained, a large fractional bandwidth was considered to be of potential benefit for radar detection in severe clutter environments. A feasibility study of a short wave ultra-wideband radar started at FOA in 1985. Actual construction of the CARABAS system commenced 1987, aircraft integration took place during 1991 and the first radar tests were conducted in early 1992. From the fall of 1992 onwards, field campaigns and evaluation studies have been conducted as a joint effort between FOA and MIT Lincoln Laboratory in the US. This article will focus on experiences concerning foliage penetration with the system. First the authors touch upon the CARABAS system characteristics, outline the arguments behind a large-fractional-bandwidth VHF-band SAR approach to foliage penetration, and finally present some early experimental results. The authors refer to other papers, for a fuller explanation of the system, for more details of image calibration and for results concerning underground imaging.

Hellsten, H.; Froelind, P.O.; Gustavsson, A.; Jonsson, T.; Larsson, B.; Stenstroem, G. [National Defense Research Establishment, Linkoeping (Sweden); Binder, B.T.; Mirkin, M.; Ayasli, S. [Massachusetts Inst. of Technology, Lexington, MA (United States)

1994-12-31

93

Ultra wideband ground penetrating radar imaging of heterogeneous solids  

DOEpatents

A non-invasive imaging system for analyzing engineered structures comprises pairs of ultra wideband radar transmitters and receivers in a linear array that are connected to a timing mechanism that allows a radar echo sample to be taken at a variety of delay times for each radar pulse transmission. The radar transmitters and receivers are coupled to a position determining system that provides the x,y position on a surface for each group of samples measured for a volume from the surface. The radar transmitter and receivers are moved about the surface, e.g., attached to the bumper of a truck, to collect such groups of measurements from a variety of x,y positions. Return signal amplitudes represent the relative reflectivity of objects within the volume and the delay in receiving each signal echo represents the depth at which the object lays in the volume and the propagation speeds of the intervening material layers. Successively deeper z-planes are backward propagated from one layer to the next with an adjustment for variations in the expected propagation velocities of the material layers that lie between adjacent z-planes.

Warhus, John P. (Brentwood, CA); Mast, Jeffrey E. (Livermore, CA)

1998-01-01

94

Ultra wideband ground penetrating radar imaging of heterogeneous solids  

DOEpatents

A non-invasive imaging system for analyzing engineered structures comprises pairs of ultra wideband radar transmitters and receivers in a linear array that are connected to a timing mechanism that allows a radar echo sample to be taken at a variety of delay times for each radar pulse transmission. The radar transmitters and receivers are coupled to a position determining system that provides the x,y position on a surface for each group of samples measured for a volume from the surface. The radar transmitter and receivers are moved about the surface, e.g., attached to the bumper of a truck, to collect such groups of measurements from a variety of x,y positions. Return signal amplitudes represent the relative reflectivity of objects within the volume and the delay in receiving each signal echo represents the depth at which the object lays in the volume and the propagation speeds of the intervening material layers. Successively deeper z-planes are backward propagated from one layer to the next with an adjustment for variations in the expected propagation velocities of the material layers that lie between adjacent z-planes. 11 figs.

Warhus, J.P.; Mast, J.E.

1998-11-10

95

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

96

Optimal Waveforms Design for Ultra-Wideband Impulse Radio Sensors  

PubMed Central

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

97

Ultra-Wideband Angle-of-Arrival Tracking Systems  

NASA Technical Reports Server (NTRS)

Systems that measure the angles of arrival of ultra-wideband (UWB) radio signals and perform triangulation by use of those angles in order to locate the sources of those signals are undergoing development. These systems were originally intended for use in tracking UWB-transmitter-equipped astronauts and mobile robots on the surfaces of remote planets during early stages of exploration, before satellite-based navigation systems become operational. On Earth, these systems could be adapted to such uses as tracking UWB-transmitter-equipped firefighters inside buildings or in outdoor wildfire areas obscured by smoke. The same characteristics that have made UWB radio advantageous for fine resolution ranging, covert communication, and ground-penetrating radar applications in military and law-enforcement settings also contribute to its attractiveness for the present tracking applications. In particular, the waveform shape and the short duration of UWB pulses make it possible to attain the high temporal resolution (of the order of picoseconds) needed to measure angles of arrival with sufficient precision, and the low power spectral density of UWB pulses enables UWB radio communication systems to operate in proximity to other radio communication systems with little or no perceptible mutual interference.

Arndt, G. Dickey; Ngo, Phong H.; Phan, Chau T.; Gross, Julia; Ni, Jianjun; Dusl, John

2010-01-01

98

Signal processing techniques for stepped frequency ultra-wideband radar  

NASA Astrophysics Data System (ADS)

The U.S. Army Research Laboratory (ARL) has developed the impulse-based, ground vehicle-based, forward-looking ultra-wideband (UWB), synthetic aperture radar (SAR) to detect concealed targets. Although the impulse-based architecture offers its own advantages, one of the important challenges is that when using this architecture it is very difficult to transmit a radar signal with an arbitrary bandwidth and shape. This feature is crucial for the radar to be compliant with the local frequency authority. In addition, being able to transmit signals with an arbitrary spectral shape is an important step in creating the next generation of smart (cognitive) radars. Therefore, we have designed a next-generation prototype radar to take advantage of the stepped frequency architecture. The design and building of the radar hardware is underway. In this paper, we study the radar transmit and acquisition scheme; the trade-offs between SAR image performance and various key radar parameters; and data reconstruction techniques for radar signals with an arbitrary spectrum. This study demonstrates performance, provides some guidelines for the radar design, and serves as a foundation for the signal and image processing stage.

Nguyen, Lam

2014-05-01

99

Compact Wide Stopband Ultra Wideband Bandpass Filter Using Multilayer Liquid Crystal Polymer Technology  

Microsoft Academic Search

Novel ultra-wideband (UWB) bandpass filters (BPFs) are proposed based on broadside coupled capacitive-loaded transmission line resonators (C-L TLR) in this letter. By utilizing the wideband harmonic suppression behavior of C-L TLR, the proposed UWB BPFs were designed with wide stopband and implemented using multilayer organic liquid crystal polymer (LCP) technology. As demonstrations, a vialess five-pole BPF was designed first, and

Zhang-Cheng Hao; Jia-Sheng Hong

2009-01-01

100

Wideband Dynamic Radio Spectra of Two Ultra-cool Dwarfs  

NASA Astrophysics Data System (ADS)

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 TVLM 0513-46 and 2M 0746+20. We combine these observations with archival radio data to fully characterize both the temporal and spectral properties of the radio emission. The continuum spectral energy distribution can be well modeled using gyrosynchrotron emission from mildly relativistic electrons in a dipolar field. The pulsed emission exhibits a variety of time-variable characteristics, including frequency drifts, frequency cutoffs, and multiple pulses per period. For 2M 0746+20 we determine a pulse period consistent with previously determined values. We modeled locations of pulsed emission using an oblique rotating magnetospheric model with beamed electron-cyclotron maser (ECM) sources. The best-fit models have narrow ECM beaming angles aligned with the local source magnetic field direction, except for one isolated burst from 2M 0746+20. For TVLM 0513-46, the best-fit rotation axis inclination is nearly orthogonal to the line of sight. For 2M 0746+20 we found a good fit using a fixed inclination i=36{}^\\circ , determined from optical observations. For both stars the ECM sources are located near feet of magnetic loops with radial extents 1.2Rs–2.7Rs and surface fields 2.2–2.5 kG. These results support recent suggestions that radio over-luminous UCDs have a global “weak field” non-axisymmetric magnetic topologies.

Lynch, C.; Mutel, R. L.; Güdel, M.

2015-04-01

101

Ultra-Wideband Optical Modulation Spectrometer (OMS) Development  

NASA Technical Reports Server (NTRS)

The optical modulation spectrometer (OMS) is a novel, highly efficient, low mass backend for heterodyne receiver systems. Current and future heterodyne receiver systems operating at frequencies up to a few THz require broadband spectrometer backends to achieve spectral resolutions of R approximately 10(exp 5) to 10(exp 6) to carry out many important astronomical investigations. Among these are observations of broad emission and absorption lines from extra-galactic objects at high redshifts, spectral line surveys, and observations of planetary atmospheres. Many of these lines are pressure or velocity broadened with either large half-widths or line wings extending over several GHz. Current backend systems can cover the needed bandwidth only by combining the output of several spectrometers, each with typically up to 1 GHz bandwidth, or by combining several frequency-shifted spectra taken with a single spectrometer. An ultra-wideband optical modulation spectrometer with 10 - 40 GHz bandwidth will enable broadband ob- servations without the limitations and disadvantages of hybrid spectrometers. Spectrometers like the OMS will be important for both ground-based observatories and future space missions like the Single Aperture Far-Infrared Telescope (SAFIR) which might carry IR/submm array heterodyne receiver systems requiring a spectrometer for each array pixel. Small size, low mass and small power consumption are extremely important for space missions. This report summarizes the specifications developed for the OMS and lists already identified commercial parts. The report starts with a review of the principle of operation, then describes the most important components and their specifications which were derived from theory, and finishes with a conclusion and outlook.

Gardner, Jonathan (Technical Monitor); Tolls, Volker

2004-01-01

102

Ultra-wideband polarization conversion metasurfaces based on multiple plasmon resonances  

NASA Astrophysics Data System (ADS)

We propose to realize ultra-wideband polarization conversion metasurfaces in microwave regime through multiple plasmon resonances. An ultra-wideband polarization conversion metasurface is designed using a double-head arrow structure and is further demonstrated both numerically and experimentally. Four plasmon resonances are generated by electric and magnetic resonances, which lead to bandwidth expansion of cross-polarization reflection. The simulated results show that the maximum conversion efficiency is nearly 100% at the four plasmon resonance frequencies and a 1:4 3 dB bandwidth can be achieved for both normally incident x- and y-polarized waves. Experimental results agree well with simulation ones.

Chen, Hongya; Wang, Jiafu; Ma, Hua; Qu, Shaobo; Xu, Zhuo; Zhang, Anxue; Yan, Mingbao; Li, Yongfeng

2014-04-01

103

Ultra-wideband communication system prototype using orthogonal frequency coded SAW correlators.  

PubMed

This paper presents preliminary ultra-wideband (UWB) communication system results utilizing orthogonal frequency coded SAW correlators. Orthogonal frequency coding (OFC) and pseudo-noise (PN) coding provides a means for spread-spectrum UWB. The use of OFC spectrally spreads a PN sequence beyond that of CDMA; allowing for improved correlation gain. The transceiver approach is still very similar to that of the CDMA approach, but provides greater code diversity. Use of SAW correlators eliminates many of the costly components that are typically needed in the intermediate frequency (IF) section in the transmitter and receiver, and greatly reduces the signal processing requirements. Development and results of an experimental prototype system with center frequency of 250 MHz are presented. The prototype system is configured using modular RF components and benchtop pulse generator and frequency source. The SAW correlation filters used in the test setup were designed using 7 chip frequencies within the transducer. The fractional bandwidth of approximately 29% was implemented to exceed the defined UWB specification. Discussion of the filter design and results are presented and are compared with packaged device measurements. A prototype UWB system using OFC SAW correlators is demonstrated in wired and wireless configurations. OFC-coded SAW filters are used for generation of a transmitted spread-spectrum UWB and matched filter correlated reception. Autocorrelation and cross-correlation system outputs are compared. The results demonstrate the feasibility of UWB SAW correlators for use in UWB communication transceivers. PMID:23475929

Gallagher, Daniel R; Kozlovski, Nikolai Y; Malocha, Donald C

2013-03-01

104

Power line communications (PLC) using impulse ultra wideband (UWB) in a microprocessor had been  

E-print Network

Abstract Power line communications (PLC) using impulse ultra wideband (UWB) in a microprocessor had microprocessor increases rapidly and seemingly without bound, testing and debug strategies have to be constantly these variations on a microprocessor die, most of the test circuits are either removed once the chip is deployed

Ha, Dong S.

105

Compact Ultra Wide-Band (UWB) CPW-fed Elliptical Monopole on Liquid Crystal Polymer (LCP)  

E-print Network

Compact Ultra Wide-Band (UWB) CPW-fed Elliptical Monopole on Liquid Crystal Polymer (LCP) Symeon is fabricated on 100 µm thick liquid crystal polymer (LCP) with an overall board dimension of 32 mm x 30 mm monopole is proposed on a Liquid Crystal Polymer (LCP) substrate. The elliptical shape and the CPW ground

Tentzeris, Manos

106

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

E-print Network

An N-Bit Digitally Variable Ultra Wideband Pulse Generator for GPR and UWB Applications Sertac has found military applications such as ground penetrating radar (GPR), wall penetrating radar, secure are generated and the generated time pulses may span of a few GHz bandwidth. It is mostly preferred in the GPR

Yanikoglu, Berrin

107

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

108

Towards contrast enhanced breast imaging using ultra-wideband microwave radar system  

Microsoft Academic Search

In this paper we present numerical results of contrast-enhanced breast imaging using ultra-wideband microwave radar system. Due to low contrast in electrical properties between dense breast tissues and malignant tissues, tumor detection using microwave might be extremely challenging. To overcome this problem, we propose here a radar imaging technique based on a localized contrast enhancement. Our results show that microwave

M. Klemm; J. Leendertz; D. Gibbins; I. J. Craddock; A. Preece; R. Benjamin

2010-01-01

109

INTRODUCTION TO ULTRA-WIDEBAND ANTENNAS Hans Gregory Schantz (h.schantz@ieee.org)  

E-print Network

INTRODUCTION TO ULTRA-WIDEBAND ANTENNAS Hans Gregory Schantz (h.schantz@ieee.org) Next-RF, Inc. 4811Cove Creek Drive Brownsboro, AL 35741 In addition, a UWB antenna is preferentially non- dispersive- periodic antenna is an example of a dispersive antenna. Larger scale components radiate low frequency

Arslan, Hüseyin

110

A Compact Ultra-Wideband Antenna for Time-and Frequency-Domain Applications  

E-print Network

is large. 2. ANTENNA DESIGN The topology ofthe proposed antenna is shown in Fig. l(b). The antenna simulated using a FDTD based simulation software. The antennas were then fabricated and their responses wereA Compact Ultra-Wideband Antenna for Time- and Frequency- Domain Applications Nader Behdad

Sarabandi, Kamal

111

Design of Compact Dual-Polarized Printed-Circuit Antenna for Ultra-Wideband Applications  

E-print Network

Design of Compact Dual-Polarized Printed-Circuit Antenna for Ultra-Wideband Applications K. Rambabu.2 and a gain better than 2 dBi. The design is verified by commercially available software and measurements design strategies for the patch antenna with overlapping squares (Fig. 1) in order to present the design

Bornemann, Jens

112

Ultra-wideband channel modeling on the basis of information-theoretic criteria  

Microsoft Academic Search

We present results of two ultra-wideband (UWB) channel measurement campaigns in the 2-5 GHz frequency band, and use Akaike's Information Criterion (AIC) to determine suitable distributions for the channel impulse response taps. Despite the large bandwidth, AIC supports the complex Gaussian tap distribution, with mean depending on the measurement setting. We estimate the empirical covariance matrix of the channel impulse

Ulrich G. Schuster; H. Bolcskei; G. Durisi

2005-01-01

113

Rat electrocardiogram during acute exposure to synchronized bursts of ultra-wideband pulses  

Microsoft Academic Search

Rats under ketamine anesthesia were exposed to bursts of ultra-wideband (UWB) electromagnetic pulses at two different times during the electrocardiogram (ECG) to investigate possible changes in the ECG immediately after start of exposure. Animals were exposed to UWB pulses in a giga transverse electromagnetic cell (GTEM) with the body axis parallel to the direction of UWB propagation (k-polarization) or the

Ronald L. Seaman; James R. Jauchem

2004-01-01

114

Compact Cactus-Shaped Ultra Wide-Band (UWB) Monopole on Organic Symeon Nikolaou*(1)  

E-print Network

Compact Cactus-Shaped Ultra Wide-Band (UWB) Monopole on Organic Substrate Symeon Nikolaou*(1, U.S.A. simos@ece.gatech.edu Abstract: The implementation of a novel cactus-shaped monopole antenna-segments broadband antennas proposed in [4-5] do not cover the whole UWB range. In this paper, a compact cactus

Tentzeris, Manos

115

Ultra wideband system outage studies in a square cell with partial Rake receiver and lognormal fading  

Microsoft Academic Search

Ultra wideband (UWB) spread spectrum system performance is analysed in a square-shaped cell with centralised and distributed topologies. Cochannel interference induced outage probability is used as a performance measure. The probability of outage varies depending on the spatial distribution of users (link distances), propagation parameters, user activities, and receiver timing errors. Power sums of multiple lognormal signal components are approximated

Pekka Pirinen

2005-01-01

116

Development of an Ultra-Wideband Radar System for Vehicle Detection at Railway Crossings  

E-print Network

Development of an Ultra-Wideband Radar System for Vehicle Detection at Railway Crossings Stephen P in a railway crossing. Once fully developed, the detection performance of the system is to be compared against the loop the impedance changes and this change is sensed. Most railways companies prefer not to use buried

Kansas, University of

117

NOVEL ULTRA-WIDEBAND DISCONE Jinu Kim and Seong-Ook Park  

E-print Network

antenna [2]. Such a discone antenna's feeding structure can be overcome by using a small ball-type skirt untruncated structure is the skeletal biconical an- tenna. The skeletal biconical antennas for EMCNOVEL ULTRA-WIDEBAND DISCONE ANTENNA Jinu Kim and Seong-Ook Park School of Engineering Information

Park, Seong-Ook

118

Development of an ultra wideband ground penetrating radar (UWB GPR) for nondestructive testing of underground objects  

Microsoft Academic Search

A compact ground penetrating radar (GPR) using an impulse waveform is developed. The UWB GPR system is composed of an impulse generator, ultra wideband transmitting and receiving antennas, high speed digitizer, and a laptop computer for data storage and image processing. By considering the maximum measuring depth and soil properties, a proper impulse generator is made and then a novel

Younp-Jin Park; Sung-Bae Cho; Kwan-Ho Kim; Dong-Gi Youn

2004-01-01

119

An ultra-wideband wire spiral antenna for in-body communications using different material matching layers.  

PubMed

In this work an ultra-wideband wire antenna was designed and fabricated for transmitting/receiving signals to/from inside the human body. The antenna provides high gain and thus high field intensity in its broadside direction; hence, a high energy density wireless can be established with the inner body. The proposed antenna operates in the frequency band of 3-10 GHz with an impedance of 200 Ohms in free space. The antenna was embedded in different materials with permittivity values ranging from 12 to 74 in order to evaluate the matching layer effect on wave propagation from outside to inside the body. The antenna port impedance was adjusted by using matching circuits. The electric field intensity inside the human chest was calculated for different materials and depths. The best improvement in wave penetration was obtained for the frequency band of 750-1000 MHz by embedding the antenna inside a material with permittivity equal to 27. PMID:25571603

Khaleghi, Ali; Balasingham, Ilangko; Chavez-Santiago, Raul

2014-01-01

120

Fine Transmittance\\/Reflectivity Measurement System Using Single-Sideband Frequency Sweeper with Ultra-Wideband Hilbert Transformer  

Microsoft Academic Search

A wideband transmittance\\/reflectivity measurement system for fine-structured components is proposed. The optical single-sideband frequency sweeper with an ultra wideband Hilbert transformer enables excellent frequency sweep range between 2GHz-30GHz. Frequency resolution of 4.7MHz is experimentally obtained.

Tetsuya Kawanishi; Takahide Sakamoto; Daniel Fonseca; Adolfo Cartaxo; Paulo Monteiro; Masayuki Izutsu

2006-01-01

121

Ultra-Wideband Radar Measurements Over Bare and Snow-Covered Saline Ice S. Gogineniand P. Kanagaratnam  

E-print Network

Ultra-Wideband Radar Measurements Over Bare and Snow-Covered Saline Ice S. Gogineniand P. Kanagaratnam Radar Systems & Remote Sensing Laboratory University of Kansas 2291 Irving Hill Rd., Lawrence, KS-We developed an tiltra-wideband radar operating over frequencies from 500 MHz to 18 Ghz and used

Kansas, University of

122

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 3, 2004 45 A Wideband Monopole Antenna for  

E-print Network

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 3, 2004 45 A Wideband Monopole Antenna for PCS--A triple-band stubby antenna fed by a coaxial probe and tuning technique are proposed for operating at PCS, IMT-2000, and Bluetooth bands. The proposed antenna shielded by the antenna cover consists of the two

Park, Seong-Ook

123

Negative refractive index material-inspired 90-deg electrically tilted ultra wideband resonator  

NASA Astrophysics Data System (ADS)

A negative refractive index material loaded patch antenna is proposed for ultra wideband applications. The wideband operation has been achieved by creating a defected ground plane with a CNC shaped split ring resonator. The defected ground plane CNC resonator also exhibits a 90-deg electrical tilt. Two additional slots are engineered in the patch antenna for further bandwidth enhancement. A -10 dB bandwidth with an order of 57.89% has been achieved with a peak gain of 5.37 dBi at a 5.5 GHz resonant frequency. Measured results demonstrate good agreement with simulated results.

Upadhyaya, Trushit K.; Kosta, Shiv Prasad; Jyoti, Rajeev; Palandoken, Merih

2014-10-01

124

A compact LTCC ultra-wideband bandpass filter using semi-lumped parallel-resonance circuits for spurious suppression  

Microsoft Academic Search

A very compact ultra-wideband (UWB) bandpass filter with both high selectivity and suppressed spurious passband is implemented in the low-temperature co-fired ceramic (LTCC) substrate. By using the optimum distributed highpass filter structure of 11th-order, an ultra-wideband filter with the bandwidth from 3.1 GHz to 10.6 GHz is realized. In this study, the semi-lumped parallel resonance circuits are adopted in conjunction

Chung-Hwa Wu; Yo-Shen Lin; Chi-Hsueh Wang; Chun Hsiung Chen

2007-01-01

125

Dynamics of Continuous, Discrete, and Impulse Systems, Special issue on "Ultra-Wideband Wireless Communications", Vol. 12, No. 3, June 2005 pp. 297-482, ISSN 1492-8760.  

E-print Network

, there would be no controlled wireless propagation of electromagnetic waves. Without an understanding point of view, this understanding may be the most significant milestone in the UWB communication history

Qiu, Robert Caiming

126

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

127

Technical challenges in ultra-wideband radar development for target detection and terrain mapping  

Microsoft Academic Search

This paper describes two ultra-wideband synthetic radars (SAR) currently being developed. One, the Foliage Penetration Advanced Technology Demonstration, will be installed on an Army C-12 and eventually the Global Hawk Unmanned Aerial Vehicle. It is designed to detect stationary military vehicles, which are camouflaged or hidden in forests and tree-lines. It employs a VHF SAR for screening and a UHF

Mark E. Davis; Philip G. Tomlinson; R. Paul Maloney

1999-01-01

128

Ultra Wideband Bandpass Filter Using Embedded Stepped Impedance Resonators on Multilayer Liquid Crystal Polymer Substrate  

Microsoft Academic Search

This letter proposes an ultra wideband (UWB) bandpass filter (BPF) based on embedded stepped impedance resonators (SIRs). In this study, broad side coupled patches and high impedance microstrip lines are adopted as quasi-lumped elements for realizing the coupling between adjacent SIRs, which are used to suppress stopband harmonic response. An eight-pole UWB BPF is developed from lump-element bandpass prototype and

Zhang-Cheng Hao; Jia-Sheng Hong

2008-01-01

129

Ultra-Wideband Bandpass Filter Using Multilayer Liquid-Crystal-Polymer Technology  

Microsoft Academic Search

Novel ultra-wideband (UWB) bandpass filters are proposed based on quasi-lumped-element prototypes and implemented with multilayer liquid-crystal-polymer (LCP) technology. In this study, the broadside-coupled microstrip radial stubs and high-impedance microstrip lines are adopted as quasi-lumped elements for realizing compact UWB bandpass filters. By introducing a short-circuited high-impedance microstrip line as a shunt inductor and suitably designing quasi-lumped-element capacitors, a compact six-pole

Zhang-Cheng Hao; Jia-Sheng Hong

2008-01-01

130

Design and Fabrication of Ultra-Wideband Baluns Embedded in Multilayer Liquid Crystal Polymer Flex  

Microsoft Academic Search

In this paper, we present the design and fabrication of ultra-wideband (UWB) baluns embedded in multilayer liquid crystal polymer (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 and compared before and after lamination. Results show good dimensional stability of the material, a critical

Andy C. Chen; Morgan J. Chen; Anh-Vu Pham

2007-01-01

131

Microwave (De)Multiplexer for Ultra-Wideband (UWB) Non-Coherent High Data Rates Transceiver  

Microsoft Academic Search

This paper deals with the investigation of a low-loss planar multiplexer\\/demultiplexer with adjacent frequency bands for the implementation of an ultra-wideband high data rates (UWB HDR) transceiver (3.1-10.6 GHz) based on impulse radio. A 3.1-4.25 GHz microstrip passive quadriplexer built upon 2nd order filters using open-loop resonators is first designed and implemented to initiate the transceiver prototype, as well as

Stéphane Mallégol; Jean-Philippe Coupez; Christian Person; Thomas Lespagnol; Stéphane Paquelet; Alexis Bisiaux

2006-01-01

132

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

133

Clutter reduction methods in ultra wideband (UWB) radar and time\\/performance evaluation on ARM processors  

Microsoft Academic Search

In this study, principal component analysis (PCA), singular value decomposition (SVD) and independent component analysis (ICA), which are statistical signal processing methods for clutter reduction, are explained in ultra wideband (UWB) radars. In addition, how to use these methods in through wall imaging (TWI) and time\\/performance relationship on ARM Cortex A-8 processors which have floating-point mathematical operation support is examined

E. Ozturk; A. V. Atli; M. S. Mercan; A. Caliskan; I. Y. Erer

2012-01-01

134

Modeling the ultra-wideband outdoor channel: model specification and validation  

Microsoft Academic Search

In this paper we establish a geometry-based stochastic ultra-wideband channel model for gas stations. We statistically describe the two-dimensional spatial location and power of clustered scatterers, and the shape of their visibility and shadowing regions. We also separately model the diffuse part of the impulse response (i.e., the part that cannot be explained by the scatterers' multipath components), and show

Telmo Santos; Fredrik Tufvesson; Andreas F. Molisch

2010-01-01

135

Locally Coherent Ultra-Wideband Radio Channel Model for Sensor Networks in Industrial Environment  

Microsoft Academic Search

We describe a new transfer function model for the static ultra-wideband (UWB) radio channel in industrial indoor environments for SPIN (sensor, positioning, and identification network) applications. The model addresses propagation between one or more transmitter and one or more receiver positions. It is locally coherent, i.e., it accounts for small scale displacements of transmitter and receiver. It is a geometry-based

J. Kunisch; J. Pamp

2006-01-01

136

Solid-State Nanopulse Generator: Application in Ultra-wideband Bioeffects Research  

Microsoft Academic Search

This paper describes the design and characterization of an ultra-wideband (UWB) pulse (“nanopulse”) generator suitable for biomedical research. The pulser generates nanosecond-long pulses of adjustable rise time, amplitude, and duration, permitting analysis of possible bioeffects over a range of pulse characteristics. Nanopulses of 3.4 kV and 2.4 ns rise time are achieved in a 4-stage pulser circuit using ZTX415 transistors.

Ramana K. Sunkam; Rastko R. Selmic; Donald T. Haynie; Jeremiah S. Hill

2004-01-01

137

Ultra wideband signal impact on IEEE802.1 lb and Bluetooth performances  

Microsoft Academic Search

This paper presents the results of a co-existence study investigating the impact of ultra wideband (UWB) interference on IEEE802.11b and Bluetooth networks. Results are based on the experimental test measurements made at the University of Oulu, Finland using simple high power UWB transmitter prototypes as interference sources. Preliminary results showed that, under the extreme conditions of this experiment, both IEEE802.11b

M. Hamalainen; J. Saloranta; J.-P. Makela; I. Oppermann; T. Patana

2003-01-01

138

Pseudo-coherent software defined Ultra wideband transmitter for ranging and communication  

Microsoft Academic Search

In this paper a pseudo-coherent software-defined impulse-radio (IR) transmitter for the Ultra wideband (UWB) technology is presented. Due to the large available bandwidth, the transmitter is perfectly suited for implementing and testing high precision ranging and positioning systems in dense multi-path indoor environments. Simultaneously, it can offer reliable and secure communication functionalities. A pseudo-coherent transmitter offers the possibility to evaluate

Christoph J. Eisner; Arndt T. Ott; Jorg Huttner; Andreas Ziroff; Thomas F. Eibert

2012-01-01

139

Research and design on ultra-wideband dielectric hemispheric lens loaded quad-ridged horn antenna  

Microsoft Academic Search

Based on the ultra-wideband ridged horn antenna theory in communication system, a new quad-ridged horn antenna with a lens is described in this paper, which consists of a quad-ridged horn and a dielectric hemispheric lens. By simulation and optimization with CST MWS software which is based on the finite integration technique, a dual polarization dielectric lens loaded quad-ridged horn antenna

Jinghui Qiu; Ying Suo; Wei Li

2007-01-01

140

Optical Frequency Conversion for Millimeter-Wave Ultra-Wideband-Over-Fiber Systems  

Microsoft Academic Search

This letter investigates all-optical frequency conversion of ultra-wideband (UWB) signals for UWB-over-fiber up-link and down-link systems. An electrooptical Mach-Zehnder modulator is used in nonlinear regime to realize frequency up and down conversion of UWB rectangular pulse and monocycle. All-optical frequency up-conversion of rectangular pulse at 18 GHz generates undesired local oscillator centered in the up-converted UWB spectrum, whereas up-conversion of

Yannis Le Guennec; René Gary

2007-01-01

141

A lightweight, ultra wideband polarimetric W-band radar with high resolution for environmental applications  

Microsoft Academic Search

A lightweight, ultra wideband (UWB), polarimetric millimetre wave 94 GHz radar with high resolution is described for environmental and other short range applications. UWB and random signal W-band radar technologies are combined with polarimetric and super-resolution processing techniques to provide a compact remote sensing capability that is man-portable. An all-weather capability is provided for accurate and high resolution measurement of

Richard Holliday; Matt Rhys-Roberts; Duncan A. Wynn

2006-01-01

142

The Impact of Physical Layer Frontend Characteristics on Ultra-Wideband Radio  

Microsoft Academic Search

Ultra-wideband communications systems use signals with very large bandwidths and very low power-spectral densities to achieve high data-rate communications at short ranges. The frequency-dependent characteristics of system components at such large frequency ranges pose system design challenges not encountered in narrowband communications. This paper highlights some of the distortive effects on signal propagation introduced by transceiver frontend components, and their

Wasim Q. Malik; David J. Edwards; Christopher J. Stevens

2005-01-01

143

An ultra wideband communication channel model for capsule endoscopy  

Microsoft Academic Search

Capsule endoscopy is an increasingly popular alternative to a tube-based endoscope used in diagnosing gastrointestinal diseases. It enables the inspection of areas that are not easily accessible using traditional endoscopy and reduces patient discomfort. In addition to transferring high-capacity demanding image data, the capsule's wireless interface must provide a wireless link that enables real-time positioning and tracking of the capsule.

S. Stoa; Raul Chavez-Santiago; Ilangko Balasingham

2010-01-01

144

Wide-band high-efficiency printed loop antenna design for wireless communication systems  

Microsoft Academic Search

A new wide-band high-efficiency coplanar waveguide-fed printed loop antenna is presented for wireless communication systems in this paper. By adjusting geometrical parameters, the proposed antenna can easily achieve a wide bandwidth. To optimize the antenna performances, a parametric study was conducted with the aid of a commercial software, and based on the optimized geometry, a prototype was designed, fabricated, and

Tayeb A. Denidni; Hyeonjin Lee; Yeongseog Lim; Qinjiang Rao

2005-01-01

145

Ultra wide-band body area channel model  

Microsoft Academic Search

Using wireless sensors placed on a person to continuously monitor health information is a promising new application. However, there are currently no models describing the radio channel around the human body making it difficult to design a suitable communication system. To address this problem, we have simulated electromagnetic wave propagation around the body and incorporated these results into a simple

Andrew Fort; Claude Desset; Julien Ryckaert; Philippe De Doncker; Leo Van Biesen; Stephane Donnay

2005-01-01

146

Ultra-Wideband Bandpass Filters Using Quarter-Wave Short-Circuited Shunt Stubs and Quarter-Wave Series Transformers  

Microsoft Academic Search

This letter introduces a topology of a very wideband filter intended for the use in ultra-wideband 3.1-10.6 GHz applications. Basic filter configuration consists of quarter-wave short-circuited stubs and quarter-wave series transformers. To improve the out-of-band rejection, a low-pass filter is added across the symmetry plane. The proposed component is fabricated in a planar microstrip configuration; however, the topology can be

Manseok Uhm; Kichul Kim; Dejan S. Filipovic

2008-01-01

147

Ultra-wideband radio technology: potential and challenges ahead  

Microsoft Academic Search

An unprecedented transformation in the design, deployment, and application of short-range wireless devices and services is in progress today. This trend is in line with the imminent transition from third- to fourth-generation radio systems, where heterogeneous environments are expected to prevail eventually. A key driver in this transition is the steep growth in both demand and deployment of WLANs\\/WPANs based

Domenico Porcino; Walter Hirt

2003-01-01

148

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 5, MAY 2006 2169 A Computational Study of Ultra-Wideband Versus  

E-print Network

Study of Ultra-Wideband Versus Narrowband Microwave Hyperthermia for Breast Cancer Treatment Mark (NB) microwave hyperthermia for breast cancer treatment with a recently proposed ultra-wideband (UWB) and thermal simulations with realistic numerical breast phantoms derived from magnetic resonance images (MRIs

Hagness, Susan C.

149

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

150

Design and development of a small compact ultra wideband antenna  

NASA Astrophysics Data System (ADS)

In this paper the design of a novel and compact U slot UWB printed monopole microstrip antenna of size 19.2 × 28.8 mm2 has been presented for wireless applications. The planar, small and thin UWB antenna design consists of a U slot radiator fed by a single 50? microstrip line with truncated ground plane is excited by a coaxial SMA connector. The simulations are done using the Ansoft High Frequency Structure Simulator (HFSS) software tool. The simulated results of impedance bandwidth are well supported by measurement. The measured group delay and radiation pattern results are also presented and performance of the antenna is analyzed/discussed.

Qurratulain; Chattoraj, Neela

2013-04-01

151

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

152

Ultra-wideband short-pulse radar with range accuracy for short range detection  

DOEpatents

An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

2014-10-07

153

Compact electromagnetic bandgap structures for notch band in ultra-wideband applications.  

PubMed

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

154

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

155

CCS: a railway corridor control system utilizing ultra wideband radio technology  

Microsoft Academic Search

Ultra wide band (UWB) radio is a unique technology, which combines a megabit wireless local area network with a centimeter-resolution radiolocation (RADAR) capability over, distances less than 100 meters. A linear chain of UWB nodes can be used to create a hop-by-hop data transmission network, which also forms a RADAR \\

Paul A. Flaherty

2004-01-01

156

Exposure assessment procedures in presence of wideband digital wireless networks.  

PubMed

The article analyses the applicability of traditional methods, as well as recently proposed techniques, to the exposure assessment of electromagnetic field generated by wireless transmitters. As is well known, a correct measurement of the electromagnetic field is conditioned by the complexity of the signal, which requires dedicated instruments or specifically developed extrapolation techniques. Nevertheless, it is also influenced by the typology of the deployment of the transmitting and receiving stations, which varies from network to network. These aspects have been intensively analysed in the literature and several cases of study are available for review. The present article collects the most recent analyses and discusses their applicability to different scenarios, typical of the main wireless networking applications: broadcasting services, mobile cellular networks and data access provisioning infrastructures. PMID:19914966

Trinchero, D

2009-12-01

157

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

158

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.

159

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

160

Design, Modeling and Numerical Analysis of Microwave and Optical Devices: The Multi-band Patch Antenna, Ultra Wideband Ring Filter and Plasmonic Waveguide Coupler  

E-print Network

In this dissertation, three devices are studied and devised for the applications in microwave and optical communication: (1) Multiband Patch Antenna, (2) Ultra-Wideband Band Pass Ring Filter and (3) Plasmonic Waveguide Coupler with High Coupling...

Liu, Ya-Chi

2014-01-14

161

UTag: Long-range Ultra-wideband Passive Radio Frequency Tags  

SciTech Connect

Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

Dowla, F

2007-03-14

162

Full-duplex multiband orthogonal frequency division multiplexing ultra-wideband over fiber system  

NASA Astrophysics Data System (ADS)

A full-duplex multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband over fiber (UWBoF) system is proposed, and bidirectional transmission of a 1.28-Gbps MB-OFDM UWB signal over 50-km standard single-mode fiber (SSMF) is demonstrated. An optical remote heterodyning mixing scheme is employed to generate a 60-GHz optical millimeter wave. Meanwhile, an optical carrier without modulation data is extracted by using a fiber Bragg grating for the uplink MB-OFDM UWB signal transmission. After 50-km SSMF transmission at a bit error rate of 1×10-4, the power penalties are 0.7 dB for a 4 quadrature amplitude modulation (QAM)-uplink and 1.0 dB for a 16QAM-uplink, respectively. The proposed scheme would greatly reduce the cost and significantly improve the spectrum utilization efficiency in the full-duplex MB-OFDM UWBoF systems.

He, Jing; Wen, Xuejie; Chen, Ming; Chen, Lin; Su, Jinshu

2015-01-01

163

Utilizing Symmetry of Planar Ultra-Wideband Antennas for Size Reduction and Enhanced Performance  

E-print Network

With the increasingly new ultra wide-band applications, antenna researchers face huge challenges in designing novel operational geometries. Mono-pole and quasi-mono-pole antennas are seen to be the most compact and easily incorporate able solution for portable devices taking the advantages of printed circuit board (PCB) techniques. Most antennas of such type have symmetrical structures. It is possible to attain wider operating bandwidths by meeting symmetry conditions while chopping the antenna into halves for a compact structure. However, there is no generalized way of applying such a technique. The presented paper addresses this issue by proposing a common feeding technique that can be applied to any antenna which is miniaturized using its symmetrical structure. The proposed technique enables feeding the halved structure to achieve wider and better impedance matching than the reported full-size antennas. The theory of characteristic modes is applied to quasi-mono-pole structures to get an insight of the ant...

Mobashsher, Ahmed Toaha

2015-01-01

164

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

165

a Novel Small Printed Ultra-Wideband Antenna for Near-Field Imaging  

NASA Astrophysics Data System (ADS)

Ultra-wideband (UWB) antennas have been suggested recently for use in near field imaging systems. A small printed antenna is introduced with L-shaped reduced ground-plane to achieve UWB characteristics. The ground is optimized to allow reconfiguration of the inspection system to various operation sub-bands. Design and optimization of antenna characteristics including matching and bandwidth are performed using FDTD computational modeling of the antenna in free space as well as in the proximity to human head phantom. Effect of tumor model is investigated on field map values. Experimental validation of antenna characteristics is studied using human brain simulating liquid, and implementing a six-degree-of-freedom robot to control the scanning of the measurement sensors. Results of this research should help enhance UWB systems as promising nondestructive and noninvasive imaging tools.

Elshafiey, Ibrahim; Sheta, Abdel-Fattah; Alkanhal, Majeed A.; Alhekail, Zeyad; AlOrainy, Abdullah

2009-03-01

166

Design Considerations for Ultra-Low Energy Wireless Microsensor Nodes  

E-print Network

. The most familiar sources of ambient energy include solar power, thermal gradients, radio-frequency (RF to retain local energy storage. Coupling energy- harvesting techniques with some form of energy storage canDesign Considerations for Ultra-Low Energy Wireless Microsensor Nodes Benton H. Calhoun, Student

Chandrakasan, Anantha

167

A Study and Practice on the Wireless Networking Curriculum  

Microsoft Academic Search

The ongoing development of wireless networking produces a lot of new technologies and applications, such as Ultra Wideband (UWB) and Wireless Sensor Networks (WSN). For traditional wired networking curriculums, the teaching is relatively easy due to the mature and stable measures. However, different from the traditional wired networking teaching, the Wireless Networking Teaching (WNT) is facing new challenges due to

Xianliang Jiang; Guang Jin; Xiaodong Wang; Cuixia Ni; Zhijun Xie

2011-01-01

168

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

169

Ultra-wideband double vertical knife-edge model for obstruction of a ray by a person  

Microsoft Academic Search

We present a novel simple analytical model for the shadowing caused by a person that moves through an ultra-wideband ray. The model uses two vertical knife-edges plus phase and amplitude correction terms to determine the loss caused by the person at different perpendicular distances to the ray. In conjunction with the personpsilas trajectory the time-dependent shadowing loss can be determined,

J. Kunisch; J. Pamp

2008-01-01

170

An Electronic Circuit System for Time-Reversal of Ultra-Wideband Short Impulses Based on Frequency-Domain Approach  

Microsoft Academic Search

In this paper, a compact and low-cost electronic circuit system is designed for time-reversal of ultra-wideband short impulses (with nanosecond and sub-nanosecond temporal durations). A frequency-domain approach is adopted to avoid high sampling rate in time. Specifically, the proposed system obtains the discrete spectra of input impulses first; then realizes time-reversal in frequency domain; and finally synthesizes the time-reversed impulses

Huiqing Zhai; Shaoshu Sha; Varun K. Shenoy; Sungyong Jung; Mingyu Lu; Kyoungwon Min; Sungchul Lee; Dong S. Ha

2010-01-01

171

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

172

Photonic generation of ultra-wideband pulses using a fiber delay interferometer  

NASA Astrophysics Data System (ADS)

We demonstrate a novel scheme to generate ultra wideband (UWB) doublet pulses by inputting a dark return-to-zero (RZ) signal into a fiber delay interferometer (FDI). When a dark RZ pulse train with a repetition rate of 0.625 GHz and a pulse width of 120 ps was inputted into a FDI with a free spectrum range (FSR) of 0.16 nm (~20 GHz, according time delay is ~50 ps) and an extinction ratio (ER) of 9 dB, by adjusting the control temperature of the FDI, the phase difference of the input light on the both fiber arms of the FDI is changed and controlled, UWB doublet pulse is directly generated at the output port of the FDI. The system parameters effects on the output signal were also discussed. Moreover, we numerically demonstrated that, by carefully optimizing system parameters, UWB quadruplet pulses also can be generated. This scheme has some distinct advantages including easy integration, convenient tuning, good stability, and so on. Presented method also accords with the general features in future applied UWB system, namely, single optical source input, simple configuration and passive device.

Wang, Fei; Zhang, Xinliang; Zhang, Yin; Xu, Enming

2011-11-01

173

Photonic generation of ultra-wideband pulses using a fiber delay interferometer  

NASA Astrophysics Data System (ADS)

We demonstrate a novel scheme to generate ultra wideband (UWB) doublet pulses by inputting a dark return-to-zero (RZ) signal into a fiber delay interferometer (FDI). When a dark RZ pulse train with a repetition rate of 0.625 GHz and a pulse width of 120 ps was inputted into a FDI with a free spectrum range (FSR) of 0.16 nm (~20 GHz, according time delay is ~50 ps) and an extinction ratio (ER) of 9 dB, by adjusting the control temperature of the FDI, the phase difference of the input light on the both fiber arms of the FDI is changed and controlled, UWB doublet pulse is directly generated at the output port of the FDI. The system parameters effects on the output signal were also discussed. Moreover, we numerically demonstrated that, by carefully optimizing system parameters, UWB quadruplet pulses also can be generated. This scheme has some distinct advantages including easy integration, convenient tuning, good stability, and so on. Presented method also accords with the general features in future applied UWB system, namely, single optical source input, simple configuration and passive device.

Wang, Fei; Zhang, Xinliang; Zhang, Yin; Xu, Enming

2012-02-01

174

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

175

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

176

Fiber-distributed Ultra-wideband noise radar with steerable power spectrum and colorless base station.  

PubMed

A fiber-distributed Ultra-wideband (UWB) noise radar was achieved, which consists of a chaotic UWB noise source based on optoelectronic oscillator (OEO), a fiber-distributed transmission link, a colorless base station (BS), and a cross-correlation processing module. Due to a polarization modulation based microwave photonic filter and an electrical UWB pass-band filter embedded in the feedback loop of the OEO, the power spectrum of chaotic UWB signal could be shaped and notch-filtered to avoid the spectrum-overlay-induced interference to the narrow band signals. Meanwhile, the wavelength-reusing could be implemented in the BS by means of the distributed polarization modulation-to-intensity modulation conversion. The experimental comparison for range finding was carried out as the chaotic UWB signal was notch-filtered at 5.2 GHz and 7.8 GHz or not. Measured results indicate that space resolution with cm-level could be realized after 3-km fiber transmission thanks to the excellent self-correlation property of the UWB noise signal provided by the OEO. The performance deterioration of the radar raised by the energy loss of the notch-filtered noise signal was negligible. PMID:24663829

Zheng, Jianyu; Wang, Hui; Fu, Jianbin; Wei, Li; Pan, Shilong; Wang, Lixian; Liu, Jianguo; Zhu, Ninghua

2014-03-10

177

Hyperactivity caused by a nitric oxide synthase inhibitor is countered by ultra-wideband pulses.  

PubMed

Potential action of ultra-wideband (UWB) electromagnetic field pulses on effects of N(G)-nitro- L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), on nociception and locomotor activity was investigated in CF-1 mice. Animals were injected IP with saline or 50 mg/kg L-NAME and exposed for 30 min to no pulses (sham exposure) or UWB pulses with electric field parameters of 102+/-1 kV/m peak amplitude, 0.90+/-0.05 ns duration, and 160+/-5 ps rise time (mean+/-S.D.) at 600/s. Animals were tested for thermal nociceptive responses on a 50 degrees C surface and for spontaneous locomotor activity for 5 min. L-NAME by itself increased mean first-response (paw lift, shake, or lick; jump) and back-paw-lick response latencies and mean locomotor activity. Exposure to UWB pulses reduced the L-NAME-induced increase in back-paw-lick latency by 22%, but this change was not statistically significant. The L-NAME-induced hyperactivity was not present after UWB exposure. Reduction and cancellation of effects of L-NAME suggest activation of opposing mechanism(s) by the UWB pulses, possibly including increase of nitric oxide production by NOS. The action, or actions, of UWB pulses appears to be more effective on locomotor activity than on thermal nociception in CF-1 mice. PMID:10495308

Seaman, R L; Belt, M L; Doyle, J M; Mathur, S P

1999-10-01

178

Simulating ultra-wideband imaging for the early detection of tissue injury  

NASA Astrophysics Data System (ADS)

Various medical imaging techniques exist to detect the early development of tissue damage. However, a widely commercialized device that can be easily used and is cost effective is still needed. Through a literature review, we examined ultrasound, microwave tomography, and ultra-wideband (UWB) technology. Out of these techniques, UWB is the most promising since it has the capability to detect small adjustments in dielectric properties, which can change with minor alterations in perfusion and internal pressure. These minor alterations are vital in detecting the onset of ischemia, which precedes many serious conditions affecting tissue health. In addition to its ability in detection, UWB also has the potential to become a widely accessible technology to hospitals. Using software called XFdtd, we simulated ultrawideband pulses propagating through planes designed to resemble tissue in its dielectric properties. After testing several sizes of the horn antenna and configurations for the wire and port, the antenna's near field was finally able to reach the distance necessary to penetrate the tissue model. The resulting graph of voltage versus time was generated from the received antenna signal and it will be compared to the graphs that result after the dielectric properties of the model have been changed to simulate tissue injury. Through this manipulation of the tissue model, the sensitivity and selectivity of UWB in measuring small fluctuations in perfusion can be determined. In this future work with XFdtd, we want to show that UWB is a novel and viable technique in detecting early tissue injury.

Niu, Weihong; Hlavaty, Kelan; Tanska, Daria; Tseng, Nancy; Li, Jia; Penprase, Barbara

2009-02-01

179

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

180

Achieving wide-band linear-to-circular polarization conversion using ultra-thin bi-layered metasurfaces  

NASA Astrophysics Data System (ADS)

In this paper, we propose to achieve wideband linear-to-circular (LTC) polarization conversion by ultra-thin bi-layered metasurfaces. As an example, an LTC polarization conversion metasurface operating in 11.4-14.3 GHz is designed and fabricated, which is composed of two layers of metallic pattern arrays separated by a 1.5 mm-thick dielectric spacer. When linearly polarized waves impinge on the bi-layered metasurface, LTC polarization conversion transmission is greater than 90% over a wide frequency range from 11.0 GHz to 18.3 GHz. Meanwhile, the axis ratio is lower than 3 dB in 9.8-18.3 GHz. This wide-band and highly efficient LTC polarization conversion transmission is analyzed theoretically. The measured LTC polarization conversion transmissions are well consistent with the simulated results.

Li, Yongfeng; Zhang, Jieqiu; Qu, Shaobo; Wang, Jiafu; Zheng, Lin; Pang, Yongqiang; Xu, Zhuo; Zhang, Anxue

2015-01-01

181

Ultra Low Power Signal Oriented Approach for Wireless Health Monitoring  

PubMed Central

In recent years there is growing pressure on the medical sector to reduce costs while maintaining or even improving the quality of care. A potential solution to this problem is real time and/or remote patient monitoring by using mobile devices. To achieve this, medical sensors with wireless communication, computational and energy harvesting capabilities are networked on, or in, the human body forming what is commonly called a Wireless Body Area Network (WBAN). We present the implementation of a novel Wake Up Receiver (WUR) in the context of standardised wireless protocols, in a signal-oriented WBAN environment and present a novel protocol intended for wireless health monitoring (WhMAC). WhMAC is a TDMA-based protocol with very low power consumption. It utilises WBAN-specific features and a novel ultra low power wake up receiver technology, to achieve flexible and at the same time very low power wireless data transfer of physiological signals. As the main application is in the medical domain, or personal health monitoring, the protocol caters for different types of medical sensors. We define four sensor modes, in which the sensors can transmit data, depending on the sensor type and emergency level. A full power dissipation model is provided for the protocol, with individual hardware and application parameters. Finally, an example application shows the reduction in the power consumption for different data monitoring scenarios. PMID:22969379

Marinkovic, Stevan; Popovici, Emanuel

2012-01-01

182

Ultra low power signal oriented approach for wireless health monitoring.  

PubMed

In recent years there is growing pressure on the medical sector to reduce costs while maintaining or even improving the quality of care. A potential solution to this problem is real time and/or remote patient monitoring by using mobile devices. To achieve this, medical sensors with wireless communication, computational and energy harvesting capabilities are networked on, or in, the human body forming what is commonly called a Wireless Body Area Network (WBAN). We present the implementation of a novel Wake Up Receiver (WUR) in the context of standardised wireless protocols, in a signal-oriented WBAN environment and present a novel protocol intended for wireless health monitoring (WhMAC). WhMAC is a TDMA-based protocol with very low power consumption. It utilises WBAN-specific features and a novel ultra low power wake up receiver technology, to achieve flexible and at the same time very low power wireless data transfer of physiological signals. As the main application is in the medical domain, or personal health monitoring, the protocol caters for different types of medical sensors. We define four sensor modes, in which the sensors can transmit data, depending on the sensor type and emergency level. A full power dissipation model is provided for the protocol, with individual hardware and application parameters. Finally, an example application shows the reduction in the power consumption for different data monitoring scenarios. PMID:22969379

Marinkovic, Stevan; Popovici, Emanuel

2012-01-01

183

A Wideband Dual-Antenna Receiver for Wireless Recording From Animals Behaving in Large Arenas  

PubMed Central

A low-noise wideband receiver (Rx) is presented for a multichannel wireless implantable neural recording (WINeR) system that utilizes time-division multiplexing of pulse width modulated (PWM) samples. The WINeR-6 Rx consists of four parts: 1) RF front end; 2) signal conditioning; 3) analog output (AO); and 4) field-programmable gate array (FPGA) back end. The RF front end receives RF-modulated neural signals in the 403–490 MHz band with a wide bandwidth of 18 MHz. The frequency-shift keying (FSK) PWM demodulator in the FPGA is a time-to-digital converter with 304 ps resolution, which converts the analog pulse width information to 16-bit digital samples. Automated frequency tracking has been implemented in the Rx to lock onto the free-running voltage-controlled oscillator in the transmitter (Tx). Two antennas and two parallel RF paths are used to increase the wireless coverage area. BCI-2000 graphical user interface has been adopted and modified to acquire, visualize, and record the recovered neural signals in real time. The AO module picks three demultiplexed channels and converts them into analog signals for direct observation on an oscilloscope. One of these signals is further amplified to generate an audio output, offering users the ability to listen to ongoing neural activity. Bench-top testing of the Rx performance with a 32-channel WINeR-6 Tx showed that the input referred noise of the entire system at a Tx–Rx distance of 1.5 m was 4.58 ?Vrms with 8-bit resolution at 640 kSps. In an in vivo experiment, location-specific receptive fields of hippocampal place cells were mapped during a behavioral experiment in which a rat completed 40 laps in a large circular track. Results were compared against those acquired from the same animal and the same set of electrodes by a commercial hardwired recording system to validate the wirelessly recorded signals. PMID:23428612

Lee, Seung Bae; Yin, Ming; Manns, Joseph R.

2014-01-01

184

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

E-print Network

volume. The 18 mirrors are slow-tool diamond turned on two substrates, one at each end, to streamline-tool diamond turning, 1. INTRODUCTION Wide-band phased arrays generally use true time delay (TTD) to steer

Anderson, Betty Lise

185

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

186

Note on antenna design in UWB wireless communication systems  

Microsoft Academic Search

Requirements for the antennas in wireless communication systems are presented, from a systems point of view. Differences between narrowband and ultrawideband systems in assessing system performance are discussed. Several parameters are introduced for the antennas in ultra-wideband wireless communication systems, to evaluate the performance of antennas based on the system requirements. As an example, a transmitting\\/receiving antenna system comprising two

Xuan Hui Wu; Zhi Ning Chen; M. Y. W. Chia

2003-01-01

187

Abstract--We present a statistical model for the path loss of ultra-wideband channels in indoor environments. In contrast to  

E-print Network

Abstract-- We present a statistical model for the path loss of ultra-wideband channels in indoor); and local spatial averaging is included. As before, the center frequency is 5.0 GHz. Separate models) and non-line-of-sight (NLS) paths. All four models have the same mathematical structure, differing only

Kavcic, Aleksandar

188

Low-profile, Ultra-wideband, Cavity-backed Spiral Antennas  

NASA Astrophysics Data System (ADS)

Spiral antennas are a popular class of antennas that demonstrate exceptionally large bandwidths, uniform input impedance, stable gains and the ability to radiate circularly polarized waves over their entire frequency coverage. Circularly polarized radiators are integral components of all space-based communication, SATNAV and SATCOM services, microwave direction finding systems, GPS applications, in-flight connectivity etc. As a result, spiral and helical elements have become a distinctive branch in the field of antenna engineering. Spiral antennas are often configured with a metallic cavity that restricts the radiation to one hemisphere for unidirectional operation. With ever-decreasing dimensions of communication devices and to focus on issues concerning space constraints arising from installation of numerous antenna elements, low-profile geometries have drawn considerable research interest over the years. In this dissertation, we have addressed the problem of designing low-profile, ultra-wideband (UWB), 2-18 GHz cavity-backed spiral antennas. First, we discuss the development of UWB shallow, absorptive cavities from a microwave material characterization standpoint. We then proceed onto geometrically modifying regular spirals to obtain more compact structures that incorporate certain radiation properties. Axial ratio is one the most important bandwidth factors in measuring the performance of a circularly polarized radiator. In developing low-profile geometries, one most often encounters the problem of deterioration of the axial ratio. This is particularly evident in rectangular spiral antennas, where the purity of the circularly polarized waves is highly compromised as a tradeoff with available aperture. It therefore becomes essential to design spiral geometry in such a way so as to preserve the lowest possible antenna aperture with the best possible axial ratio performance. In our work, we have presented a detailed study of slow wave spirals, elliptical spirals and modified Archimedean polygonal spiral antenna designs that address the problem of maintaining high axial ratio performance with low-profile planar geometries. The designed antenna systems have been fabricated and tested for performance validation, and they demonstrate excellent axial ratio characteristics across their bandwidth.

Rahman, Nahid

189

Neural and behavioral teratological evaluation of rats exposed to ultra-wideband electromagnetic fields.  

PubMed

Several investigators have reported teratologic effects of electromagnetic field exposure. The majority of these studies have been performed at levels of exposure that could produce substantial heating of the animals. New and unique sources of ultra-wideband (UWB) electromagnetic fields are currently being developed and tested that are capable of generating nonthermalizing, high-peak-power, microwave (MW) pulses with nanosecond (ns) pulse widths, picosecond (ps) rise times, and an UWB of frequencies. Our study was performed to determine if teratological changes occur in rat pups as a result of (i) daily UWB exposures during gestation days 3-18, or (ii) as a result of both prenatal and postnatal (10 days) exposures. Dams were exposed either to (i) UWB irradiation from a Kentech system that emitted a 55 kV/m-peak E field, 300 ps rise time, and a 1.8 ns pulse width, average whole-body specific absorption rate 45 mW/kg; (ii) sham irradiation; or (iii) a positive control, lead (Pb) acetate solution (2000 microg/ml) continuously available in the drinking water. Offspring were examined for ontogeny (litter size, sex-ratios, weights, coat appearance, tooth-eruption, eye-opening, air-righting, and ultrasonic stress vocalizations). Male pups were tested on various performance measures (locomotor, water-maze learning, and fertilization capabilities). The pups postnatally exposed were examined for hippocampal morphology and operant behavior. Behavioral, functional, and morphological effects of UWB exposure were unremarkable with these exceptions: (i) The UWB-exposed pups emitted significantly more stress vocalizations than the sham-exposed pups; (ii) the medial-to-lateral length of the hippocampus was significantly longer in the UWB-exposed pups than in the sham-exposed animals; (iii) male offspring exposed in utero to UWB mated significantly less frequently than sham-exposed males, but when they did mate there was no difference in fertilization and offspring numbers from the sham group. There does not appear to be a unifying physiological or behavioral relationship among the significant differences observed, and our findings could be due to the expected spurious results derived when a large number of statistical comparisons are made. Significant effects found between our positive-controls and other groups on numerous measures indicates that the techniques used were sensitive enough to detect teratological effects. Bioelectromagnetics 21:524-537, 2000. Published 2000 Wiley-Liss, Inc. PMID:11015117

Cobb, B L; Jauchem, J R; Mason, P A; Dooley, M P; Miller, S A; Ziriax, J M; Murphy, M R

2000-10-01

190

Time-Frequency Transform Techniques Applied to Ultra-wideband Ground-Penetrating Radar  

NASA Astrophysics Data System (ADS)

Background Recently, Dauvignac et al [1] utilized a ground penetrating radar unit consisting of an exponentially tapered slot antenna (ETSA) of the Vivaldi type, connected to an Agilent vector network analyzer to obtain a densely-sampled profile in the anti-blast tunnel of LSBB (Low-Noise inter-Disciplinary Underground Science & Technology Laboratory) located in Rustrel, France. The frequency data, from 150 MHz to 2 GHz, was inverse Fourier-transformed to obtain the time dependent data. Simultaneously, the same profile was obtained using a RAMAC 500 MHz ground-penetrating radar unit. Initial comparison of both data sets was done in the time-domain. Data obtained from the ETSA will be inverted using a constrained least squares algorithm, in order that the depth-dependent permittivity can be inferred. As a quality control, the RAMAC data will also be inverted. The resulting permittivity profiles obtained in both inversions will be used to image water content over a depth of several meters. Proposed Research It is well-known, qualitatively in the ground penetrating radar literature that high frequencies appear at early times, but generally are attenuated at later times, essentially due to the skin effect. However, a signal-processing verification of this well-known result is needed. We propose to use the Stockwell or S transform [2] to determine the temporal location of frequencies in both of the foregoing datasets. The S transform, a short-time Fourier transform with a frequency-dependent window, will be described and applied to synthetic data. Then the application of the S transform to the RAMAC and ETSA data will be presented, after each data set has undergone the same pre-processing. The S transform is completely linear and preserves the phase of the data, which allows for easy interpretation of the operations of filtering, due to the linear inverse of the forward S transform. Thus the S transform is ideal for comparing the temporal distribution of frequency in these two datasets. BIBLIOGRAPHY [1] DAUVIGNAC J.-Y., N. FORTINO, G. SENECHAL, A. CRESP, M. YEDLIN, S. GAFFET, D. ROUSSET, and C. PICHOT, "Ultra-Wideband GPR Imaging of the Vaucluse Karst Aquifer", American Geophysical Union, Fall Meeting 2008, Abstract #NS51A-08. [2] STOCKWELL R. G., L. MANSINHA, R. P. LOWE, "Localization of the complex spectrum: the S transform", IEEE Transactions on Signal Processing, vol.44, n°4, pp 998-1001, April 1996.

Yedlin, M.; Cresp, A.; Dauviganc, J. Y.; Gaffet, S.; Sénéchal, G.; Fortino, N.; Pichot, C.; Aliferis, I.

2009-04-01

191

Model-based sub-Nyquist sampling and reconstruction technique for ultra-wideband (UWB) radar  

NASA Astrophysics Data System (ADS)

The Army Research Lab has recently developed an ultra-wideband (UWB) synthetic aperture radar (SAR). The radar has been employed to support proof-of-concept demonstration for several concealed target detection programs. The radar transmits and receives short impulses to achieve a wide-bandwidth from 300 MHz to 3000 MHz. Since the radar directly digitizes the wide-bandwidth receive signals, the challenges is to how to employ relatively slow and inexpensive analog-to-digital (A/D) converters to sample the signals with a rate that is greater than the minimum Nyquist rate. ARL has developed a sampling technique that allows us to employ inexpensive A/D converters (ADC) to digitize the widebandwidth signals. However, this technique still has a major drawback due to the longer time required to complete a data acquisition cycle. This in turn translates to lower average power and lower effective pulse repetition frequency (PRF). Compressed Sensing (CS) theory offers a new approach in data acquisition. From the CS framework, we can reconstruct certain signals or images from much fewer samples than the traditional sampling methods, provided that the signals are sparse in certain domains. However, while the CS framework offers the data compression feature, it still does not address the above mentioned drawback, that is the data acquisition must be operated in equivalent time since many global measurements (obtained from global random projections) are required as depicted by the sensing matrix ? in the CS framework. In this paper, we propose a new technique that allows the sub-Nyquist sampling and the reconstruction of the wide-bandwidth data. In this technique, each wide-bandwidth radar data record is modeled as a superposition of many backscatter signals from reflective point targets. The technique is based on direct sparse recovery using a special dictionary containing many time-delayed versions of the transmitted probing signal. We demonstrate via simulated as well as collected data that our design offers real-time (with single observation as oppose to equivalent-time with many observations) data acquisition of the wide-bandwidth radar signals using the sub-Nyquist sampling rate.

Nguyen, Lam; Tran, Trac D.

2010-04-01

192

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

193

A SDR ULTRA-WIDEBAND IMPULSE COMMUNICATION SYSTEM FOR LOW AND HIGH DATA RATES  

Microsoft Academic Search

The paper proposes a new way of considering software radio in the specific context of UWB. Due to the extremely wide-band nature of UWB signals, it is shown that a first stage of analog pre-processing is mandatory to make SDR applicable in this context, in other words to obtain flexible or multi-purpose UWB systems. But not any analog front- end

Christophe MOY; Stéphane PAQUELET; Alexis BISIAUX; Apostolos KOUNTOURIS

194

Lack of effects on heart rate and blood pressure in ketamine-anesthetized rats briefly exposed to ultra-wideband electromagnetic pulses  

Microsoft Academic Search

Fourteen Sprague-Dawley rats were exposed to pulses produced by a Bournlea ultra-wideband (UWB) pulse generator (rise time, 318-337 ps; maximum E field, 19-21 kV\\/m). Exposures at a repetition frequency of 1 kHz for 0.5 s or to repetitive pulse trains (2-s exposure periods alternating with 2 s of no exposure, for a total of 2 min) resulted in no significant

James R. Jauchem; Melvin R. Frei; Kathy L. Ryan; James H. Merritt; Michael R. Murphy

1999-01-01

195

An Integrated Ultra-Wideband Timed Array Receiver in 0.13 ?m CMOS Using a Path-Sharing True Time Delay Architecture  

Microsoft Academic Search

A fully integrated CMOS ultra-wideband 4-channel timed array receiver for high-resolution imaging application is presented. A path-sharing true time delay architecture is implemented to reduce the chip area for integrated circuits. The true time delay resolution is 15 ps and the maximum delay is 225 ps. The receiver provides 11 scan angles with almost 9 degrees of spatial resolution for

Ta-Shun Chu; Jonathan Roderick; Hossein Hashemi

2007-01-01

196

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

197

An ultra-wideband body area propagation channel Model-from statistics to implementation  

Microsoft Academic Search

Body worn wireless sensors for monitoring health information is a promising new application. In developing these sensors, a communication channel model is essential. However, there are currently few measurements or models describing propagation around the body. To address this problem, we have measured electromagnetic waves near the torso and derived relevant statistics. We find that components diffracting around the body

Andrew Fort; Claude Desset; P. de Doncker; P. Wambacq; L. Van Biesen

2006-01-01

198

Localization via ultra-wideband radios: a look at positioning aspects for future sensor networks  

Microsoft Academic Search

UWB technology provides an excellent means for wireless positioning due to its high resolution capability in the time domain. Its ability to resolve multipath components makes it possible to obtain accurate location estimates without the need for complex estimation algorithms. In this article, theoretical limits for TOA estimation and TOA-based location estimation for UWB systems have been considered. Due to

Sinan Gezici; Zhi Tian; Georgios B. Giannakis; Hisashi Kobayashi; Andreas F. Molisch; H. Vincent Poor; Zafer Sahinoglu

2005-01-01

199

Impact of Mobility on Ranging Estimation using UltraWideband Arturo Guizar*  

E-print Network

.ouni@telecom-paristech.fr 1 Introduction e-Health based on Wireless Body Area Networks (WBAN) is gaining more and more-UWB sensors. 2 System Model and Results We consider a WBAN using IR-UWB technology. For the sake of simplicity

Paris-Sud XI, Université de

200

A technique for the extraction of ultra-wideband (UWB) signals concealed in frequency band folded responses  

NASA Astrophysics Data System (ADS)

Ultra-wideband (UWB) excitation sources in radar systems have allowed for enhancement in capabilities such as target spectral response, clutter suppression, and range resolution. While generation of generic UWB signals has become easily achievable, direct acquisition, or digitization, of these bandwidths (>= 4 GHz) is not. To account for this, many UWB radar systems implement a single or multi-stage band folding technique in the receiver hardware chain which allows for the direct digitization of the UWB waveform at a smaller bandwidth (e.g., 4 GHz into 1 GHz). While the lower bandwidth allows for larger than narrowband capabilities, it reduces desired features such as range resolution (e.g., 3.75 cm to 15 cm). In an effort to address this problem, and allow for utilization of full bandwidth of an UWB waveform, this paper presents a signal processing technique which utilizes hardware band folding to wrap a spectrally unique UWB multi-tone waveform into a lower frequency, lower bandwidth signal allowing for both direct digitization and conservation of UWB features. The signal processing technique utilizes the multi-tone waveform to generate an UWB signal composed of sections whose separate spectral peaks fold into the inner ?F regions of the previous band. It will be shown, that through reassignment of these peaks, as well as the phase, to the individual frequencies, the intended UWB capabilities can be restored.

Vela, Russell; Narayanan, Ram M.; Erisman, David

2011-06-01

201

Remote Monitoring and Tracking of UF6 Cylinders Using Long-Range Passive Ultra-wideband (UWB) RFID Tags  

SciTech Connect

An IAEA Technical Meeting on Techniques for IAEA Verification of Enrichment Activities identified 'smart tags' as a technology that should be assessed for tracking and locating UF6 cylinders. Although there is vast commercial industry working on RFID systems, the vulnerabilities of commercial products are only beginning to emerge. Most of the commercially off-the-shelf (COTS) RFID systems operate in very narrow frequency bands, making them vulnerable to detection, jamming and tampering and also presenting difficulties when used around metals (i.e. UF6 cylinders). Commercial passive RFID tags have short range, while active RFID tags that provide long ranges have limited lifetimes. There are also some concerns with the introduction of strong (narrowband) radio frequency signals around radioactive and nuclear materials. Considering the shortcomings of commercial RFID systems, in their current form, they do not offer a promising solution for continuous monitoring and tracking of UF6 cylinders. In this paper, we identify the key challenges faced by commercial RFID systems for monitoring UF6 cylinders, and introduce an ultra-wideband approach for tag/reader communications that addresses most of the identified challenges for IAEA safeguards applications.

Nekoogar, F; Dowla, F

2007-06-06

202

Three-Dimensional Planetary Surface Tracking Based on a Simple Ultra-Wideband Impulse-Radio Infrastructure  

NASA Technical Reports Server (NTRS)

Several prototype ultra-wideband (UWB) impulse-radio (IR) tracking systems are currently under development at NASA Johnson Space Center (JSC). These systems are being studied for use in tracking of Lunar/Mars rovers and astronauts during early exploration missions when satellite navigation systems (such as GPS) are not available. To date, the systems that have been designed and tested are intended only for two-dimensional location and tracking, but these designs can all be extended to three-dimensional tracking with only minor modifications and increases in complexity. In this presentation, we will briefly review the design and performance of two of the current 2-D systems: one designed specifically for short-range, extremely high-precision tracking (approximately 1-2 cm resolution) and the other designed specifically for much longer range tracking with less stringent precision requirements (1-2 m resolution). We will then discuss a new multi-purpose system design based on a simple UWB-IR architecture that can be deployed easily on a planetary surface to support arbitrary three-dimensional localization and tracking applications. We will discuss utilization of this system as an infrastructure to provide both short-range and long-range tracking and analyze the localization performance of the system in several different configurations. We will give theoretical performance bounds for some canonical system configurations and compare these performance bounds with both numerical simulations of the system as well as actual experimental system performance evaluations.

Barton, Richard J.; Ni, David; Ngo, Phong

2010-01-01

203

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

204

Compact Ultra Wide-Band (UWB) CPW-fed Elliptical Monopole on Liquid Crystal Polymer (LCP)  

Microsoft Academic Search

The implementation of a compact coplanar waveguide (CPW)-fed elliptical monopole antenna that demonstrates good impedance match and omni-directional radiation patterns in the whole ultra wide band range (UWB) is discussed. The proposed antenna is fabricated on 100 mum thick liquid crystal polymer (LCP) with an overall board dimension of 32 mm times 30 mm. Return loss and radiation pattern measurements

Symeon Nikolaou; Dimitrios E. Anagnostou; George E. Ponchak; Manos M. Tentzeris; John Papapolymerou

2006-01-01

205

Ultra-Wideband Optical Modulation Spectrometer (OMS) Development: Study of the Optical Setup of a Wide-Band Optical Modulation Spectrometer  

NASA Technical Reports Server (NTRS)

The purpose of this study is to advance the design of the optical setup for a wide-band Optical Modulation Spectrometer (OMS) for use with astronomical heterodyne receiver systems. This report describes the progress of this investigation achieved from March until December 2001.

Tolls, Volker; Stringfellow, Guy (Technical Monitor)

2001-01-01

206

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

E-print Network

transmission (WPT) systems to collect microwave power and convert this power into useable DC power. iv They find use in many areas such as space power transmission, RFID tags, wireless sensors, and recycling ambient microwave energy. The ability...

Hansen, Jonathan Noel

2012-02-14

207

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

208

Lack of effects on heart rate and blood pressure in ketamine-anesthetized rats briefly exposed to ultra-wideband electromagnetic pulses.  

PubMed

Fourteen Sprague-Dawley rats were exposed to pulses produced by a Bournlea ultra-wideband (UWB) pulse generator (rise time, 318-337 ps; maximum E field, 19-21 kV/m). Exposures at a repetition frequency of 1 kHz for 0.5 s or to repetitive pulse trains (2-s exposure periods alternating with 2 s of no exposure, for a total of 2 min) resulted in no significant changes in heart rate or mean arterial blood pressure. These results suggest that acute whole-body exposure to UWB pulses does not have a detrimental effect on the cardiovascular system. PMID:9919833

Jauchem, J R; Frei, M R; Ryan, K L; Merritt, J H; Murphy, M R

1999-01-01

209

Investigation of the Performance of Microring Lasers as Tunable Transmitters for Application in Future WDM/Ultra Wideband (UWB)-over-Fiber Hybrid Networks  

NASA Astrophysics Data System (ADS)

The performance of tunable directly modulated 1.55-?m InGaAsP/InP microring lasers is investigated for the case of multiband orthogonal frequency division multiplexing (MB-OFDM) signal transmission, for application in ultra wideband (UWB)-over-fiber links. The assessment is based on numerical results derived from a multimode rate equation model. The properties of the microring laser are examined both qualitatively and quantitatively via typical constellation diagrams and error vector magnitude (EVM) calculations, respectively. The results depict a minimum EVM of less than 10% when the modulation ratio is in the order of 0.17 to 0.27.

Karabetsos, S.; Mikroulis, S.; Pikasis, E.; Nassiopoulos, A.; Bogris, A.; Syvridis, D.

2010-11-01

210

The propagation and scattering characteristics of a forest as measured by coherent ultra-wideband foliage penetration  

NASA Astrophysics Data System (ADS)

Coherent polarimetric synthetic aperture radar (SAR) measurements of a central Ohio forest have been collected, and it is the objective of this research to document and analyze the results. The foliage data presented in this dissertation are unique in several aspects. Primarily, the data are Ultra-Wideband (UWB) in that the bandwidth (200-1600MHz) divided by center frequency is at least 25% and are of a wavelength selected to penetrate the forest canopy. Data of this bandwidth or resolution offer the opportunity to see for the first time at these frequencies scattering components such as branches, tree trunks, and ground-tree interaction terms. Secondly, coherent apertures were collected by precisely moving the antennas within a well-known coordinate system leading to absolute phase calibration and to the generation of fully coherent SAR imagery. Much of the past work performed on foliage propagation and scattering does not include phase information which is crucial for predicting the performance of radars of this type. The underlying goals of this research are to identify the fundamental scattering mechanisms associated with the forest backscatter at these frequencies and to assess UWB usage for the concealed target detection and identification problems. To this end, methods are developed to analyze the above measurements and extract modeling parameters such as the propagation loss, phase defect, and backscatter per unit area (sigmasp{o}). The analysis of these data provide the insight needed to statistically model the forest in both forward scatter and backscatter and to determine the ability of these UWB frequencies to penetrate the forest canopy.

Gwynne, John Scott

211

Koala: Ultra-Low Power Data Retrieval in Wireless Sensor Networks Razvan Musaloiu-E.  

E-print Network

Koala: Ultra-Low Power Data Retrieval in Wireless Sensor Networks Razvan Musaloiu-E. Computer University terzis@cs.jhu.edu Abstract We present Koala, a reliable data retrieval system de- signed to operate at permille (.1%) duty cycles, essential for long term environmental monitoring networks. Koala

Amir, Yair

212

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

213

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

E-print Network

925 An Ultra-Low-Power Power Management IC for Energy-Scavenged Wireless Sensor Nodes Michael D less power and are becoming smaller as this technology matures. Scavenged- power sensor nodes are now a reality with modern processor, sensor and radio technology [1], [2]. The efficiency of the scavenger

Sanders, Seth

214

On-chip programmable ultra-wideband microwave photonic phase shifter and true time delay unit.  

PubMed

We proposed and experimentally demonstrated an ultra-broadband on-chip microwave photonic processor that can operate both as RF phase shifter (PS) and true-time-delay (TTD) line, with continuous tuning. The processor is based on a silicon dual-phase-shifted waveguide Bragg grating (DPS-WBG) realized with a CMOS compatible process. We experimentally demonstrated the generation of delay up to 19.4 ps over 10 GHz instantaneous bandwidth and a phase shift of approximately 160° over the bandwidth 22-29 GHz. The available RF measurement setup ultimately limits the phase shifting demonstration as the device is capable of providing up to 300° phase shift for RF frequencies over a record bandwidth approaching 1 THz. PMID:25361309

Burla, Maurizio; Cortés, Luis Romero; Li, Ming; Wang, Xu; Chrostowski, Lukas; Azaña, José

2014-11-01

215

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

216

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. 14 figs.

McEwan, T.E.

1998-05-26

217

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

218

Ultra-wideband microwave photonic phase shifter with a 360° tunable phase shift based on an erbium-ytterbium co-doped linearly chirped FBG.  

PubMed

A simple photonic approach to implementing an ultra-wideband microwave phase shifter based on an erbium-ytterbium (Er/Yb) co-doped linearly chirped fiber Bragg grating (LCFBG) is proposed and experimentally demonstrated. The LCFBG is designed to have a constant magnitude response over a reflection band, and a phase response that is linear and nonlinear in two sections in the reflection band. When an optical single-sideband with carrier (OSSB+C) signal is sent to the LCFBG, by locating the optical carrier at the section corresponding to the nonlinear phase response and the sideband at the section corresponding to the linear phase response, a phase shift is introduced to the optical carrier, which is then translated to the microwave signal by beating the optical carrier and the sideband at a photodetector. The tuning of the phase shift is realized by optically pumping the Er/Yb co-doped LCFBG by a 980-nm laser diode. The proposed ultra-wideband microwave photonic phase shifter is experimentally demonstrated. A phase shifter with a full 360° phase shift with a bandwidth from 10 to 40 GHz is experimentally demonstrated. PMID:24562242

Liu, Weilin; Yao, Jianping

2014-02-15

219

Short-Range Wireless Communications for Next-Generation Networks: UWB, 60 GHz Millimeter-Wave WPAN, And ZigBee  

Microsoft Academic Search

This article presents standardization, regulation, and development issues associated with short-range wireless technologies for next-generation personal area networks (PAN). Ultra-wideband (UWB) and 60 GHz millimeter-wave communication technologies promise unprecedented short-range broadband wireless communication and are the harbingers of multigigabit wireless networks. Despite the huge potential for PAN, standardization and global spectrum regulations challenge the success of UWB. On the other

Theordore Rappaport

2007-01-01

220

Photonic generation of background-free millimeter-wave ultra-wideband pulses based on a single dual-drive Mach-Zehnder modulator.  

PubMed

We propose a novel photonic approach for generating a background-free millimeter-wave (MMW) ultra-wideband (UWB) signal based on a conventional dual-drive Mach-Zehnder modulator (DMZM). One arm of the DMZM is driven by a local oscillator (LO) signal. The LO power is optimized to realize optical carrier suppressed modulation. The other arm is fed by a rectangular signal. The MMW UWB pulses are generated by truncating the continuous wave LO signal into a pulsed one in a photodetector (PD). The generated MMW UWB signal is background-free by eliminating the baseband frequency components because the optical power launched to the PD keeps constant all the time. The proposed method is theoretically analyzed and experimentally verified. The generated MMW UWB signal centered at a frequency of 26 GHz meets the Federal Communications Commission spectral mask very well. PMID:24690706

Li, Wei; Wang, Wen Ting; Sun, Wen Hui; Wang, Li Xian; Zhu, Ning Hua

2014-03-01

221

Ultra-wideband electromagnetic pulses: lack of effects on heart rate and blood pressure during two-minute exposures of rats.  

PubMed

Exposure to fast-rise-time ultra-wideband (UWB) electromagnetic pulses has been postulated to result in effects on biological tissue (including the cardiovascular system). In the current study, 10 anesthetized Sprague-Dawley rats were exposed to pulses produced by a Sandia UWB pulse generator (average values of exposures over three different pulse repetition rates: rise time, 174-218 ps; peak E field, 87-104 kV/m; pulse duration, 0.97-0.99 ns). Exposures to 50, 500 and 1000 pulses/s resulted in no significant changes in heart rate or mean arterial blood pressure measured every 30 s during 2 min of exposure and for 2 min after the exposure. The results suggest that acute UWB whole-body exposure under these conditions does not have an immediate detrimental effect on these cardiovascular system variables in anesthetized rats. PMID:9669547

Jauchem, J R; Seaman, R L; Lehnert, H M; Mathur, S P; Ryan, K L; Frei, M R; Hurt, W D

1998-01-01

222

Three-dimensional confocal imaging for breast cancer detection using CMOS Gaussian monocycle pulse transmitter and 4 × 4 ultra wideband antenna array with impedance matching layer  

NASA Astrophysics Data System (ADS)

A time-domain reflectometry breast cancer detection system was developed, which was composed of a Gaussian monocycle pulse (GMP) transmitter circuit fabricated by complementary metal oxide semiconductor (CMOS) 65 nm technology and an ultra wide-band (UWB) planar slot antenna array. The center frequency and bandwidth of the antenna were 6 and 9.2 GHz, respectively. The GMP train having the pulse width of 160 ps was generated by the 65 nm CMOS logic circuit with a core area of 0.0017 mm2 and was emitted by the 4 × 4 planar slot antenna array. The fabricated planar 4 × 4 antenna array with the matching layer could resolve the two separate 5 × 5 × 5 mm3 breast tumor phantoms, which were located at the depth of 22 mm with the spacing of 8 mm.

Sugitani, Takumi; Kubota, Shinichi; Hafiz, Mohiuddin; Xiao, Xia; Kikkawa, Takamaro

2014-01-01

223

A Wideband Built-in Antenna with Omni-Directional Radiation Pattern using Dual Radiators for Wireless Terminals  

E-print Network

. The designed antenna has been simulated using Microwave Studio(MWS). II. THE DISCRIPTION OF PROPOSED ANTENNA characteristics. FR-4 PCB substrate layer is used for miniature antenna design. The proposed antenna is fedA Wideband Built-in Antenna with Omni-Directional Radiation Pattern using Dual Radiators

Park, Seong-Ook

224

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

225

IEEE CAS Workshop on Wireless Communications and Networking  

NSDL National Science Digital Library

In September 2002, researchers from universities and technical companies from around the world met for a Workshop on Wireless Communications and Networking. The documents that can be downloaded from this Web page consist of over twenty full papers presented at the event and several more one-page research summaries. Many of the papers address low-power design and issues, while others discuss applications of ultra-wideband technology.

226

1550 IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 53, NO. 4, APRIL 2005 BER Sensitivity to Mistiming in Ultra-Wideband  

E-print Network

] and for outdoor ad hoc networking with low probability of detection and capability to overlay existing wireless impulse radio is highly sensitive to both timing acquisition and tracking errors. In particular, time of a RAKE combiner can be severely compro- mised by mistiming. Index Terms--Mistiming, performance analysis

Giannakis, Georgios

227

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

228

Optical generation of binary-phase-coded, direct-sequence ultra-wideband signals by polarization modulation and FBG-based multi-channel frequency discriminator.  

PubMed

In this paper a novel optical generation approach for binary-phase-coded, direct-sequence ultra-wideband (UWB) signals is experimentally demonstrated. Our system consists of a laser array, a polarization modulator (PolM), a fiber Bragg grating (FBG), a length of single mode fiber, and a photo detector (PD). The FBG, designed based on the superimposed, chirped grating, is used as the multi-channel frequency discriminator. The input electronic Gaussian pulse is modulated on the optical carrier by the PolM and then converted into UWB monocycle or doublet pulses sequence by the multi-channel frequency discriminator. The PolM is used so that the desired binary phase code pattern could be simply selected by adjusting the polarization state of each laser, rather than tuning the laser wavelengths. The desired UWB shape, monocycle or doublet, could be selected by tuning the FBG. Based on our proposed approach, four-chip, binary-phase-coded, DS-UWB sequences with different pulse shapes and code patterns are experimentally demonstrated. The impact of the fiber dispersion on the generated UWB pulses is also discussed in our paper. PMID:18542612

Ou, Pan; Zhang, Ye; Zhang, Chun-Xi

2008-03-31

229

Background-free millimeter-wave ultra-wideband signal generation based on a dual-parallel Mach-Zehnder modulator.  

PubMed

A novel scheme for photonic generation of a millimeter-wave ultra-wideband (MMW-UWB) signal is proposed and experimentally demonstrated based on a dual-parallel Mach-Zehnder modulator (DPMZM). In the proposed scheme, a single-frequency radio frequency (RF) signal is applied to one sub-MZM of the DPMZM to achieve optical suppressed-carrier modulation, and an electrical control pulse train is applied to the other sub-MZM biased at the minimum transmission point, to get an on/off switchable optical carrier. By filtering out the optical carrier with one of the first-order sidebands, and properly setting the amplitude of the control pulse, an MMW-UWB pulse train without the residual local oscillation is generated after photo-detection. The generated MMW-UWB signal is background-free, because the low-frequency components in the electrical spectrum are effectively suppressed. In the experiment, an MMW-UWB pulse train centered at 25 GHz with a 10-dB bandwidth of 5.5 GHz is successfully generated. The low frequency components are suppressed by 22 dB. PMID:24216925

Zhang, Fangzheng; Pan, Shilong

2013-11-01

230

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

PubMed

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. PMID:24784637

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

2014-04-01

231

Improved Resolution and Reduced Clutter in Ultra-Wideband Microwave Imaging Using Cross-Correlated Back Projection: Experimental and Numerical Results  

PubMed Central

Microwave breast cancer detection is based on the dielectric contrast between healthy and malignant tissue. This radar-based imaging method involves illumination of the breast with an ultra-wideband pulse. Detection of tumors within the breast is achieved by some selected focusing technique. Image formation algorithms are tailored to enhance tumor responses and reduce early-time and late-time clutter associated with skin reflections and heterogeneity of breast tissue. In this contribution, we evaluate the performance of the so-called cross-correlated back projection imaging scheme by using a scanning system in phantom experiments. Supplementary numerical modeling based on commercial software is also presented. The phantom is synthetically scanned with a broadband elliptical antenna in a mono-static configuration. The respective signals are pre-processed by a data-adaptive RLS algorithm in order to remove artifacts caused by antenna reverberations and signal clutter. Successful detection of a 7?mm diameter cylindrical tumor immersed in a low permittivity medium was achieved in all cases. Selecting the widely used delay-and-sum (DAS) beamforming algorithm as a benchmark, we show that correlation based imaging methods improve the signal-to-clutter ratio by at least 10?dB and improves spatial resolution through a reduction of the imaged peak full-width half maximum (FWHM) of about 40–50%. PMID:21331362

Jacobsen, S.; Birkelund, Y.

2010-01-01

232

Repeated exposure of C3H/HeJ mice to ultra-wideband electromagnetic pulses: lack of effects on mammary tumors.  

PubMed

It has been suggested that chronic, low-level exposure to radiofrequency (RF) radiation may promote the formation of tumors. Previous studies, however, showed that low-level, long-term exposure of mammary tumor-prone mice to 435 MHz or 2450 MHz RF radiation did not affect the incidence of mammary tumors. In this study, we investigated the effects of exposure to a unique type of electromagnetic energy: pulses composed of an ultra-wideband (UWB) of frequencies, including those in the RF range. One hundred C3H/HeJ mice were exposed to UWB pulses (rise time 176 ps, fall time 3.5 ns, pulse width 1.9 ns, peak E-field 40 kV/m, repetition rate 1 kHz). Each animal was exposed for 2 min once a week for 12 weeks. One hundred mice were used as sham controls. There were no significant differences between groups with respect to incidence of palpated mammary tumors, latency to tumor onset, rate of tumor growth, or animal survival. Histopathological evaluations revealed no significant differences between the two groups in numbers of neoplasms in all tissues studied (lymphoreticular tissue, thymus, respiratory, digestive and urinary tracts, reproductive, mammary and endocrine systems, and skin). Our major finding was the lack of effects of UWB-pulse exposure on promotion of mammary tumors in a well-established animal model of mammary cancer. PMID:11175673

Jauchem, J R; Ryan, K L; Frei, M R; Dusch, S J; Lehnert, H M; Kovatch, R M

2001-02-01

233

CAPACITY-MAXIMIZING RESOURCE ALLOCATION FOR DATA-AIDED TIMING AND CHANNEL ESTIMATION IN ULTRA-WIDEBAND RADIOS  

E-print Network

CAPACITY-MAXIMIZING RESOURCE ALLOCATION FOR DATA-AIDED TIMING AND CHANNEL ESTIMATION IN ULTRA) communications relies critically on the accuracy of synchronization and channel estimation during the training phase. The total transmission resources should be properly allocated between training and information

Tian, Zhi "Gerry"

234

Ultra wideband (0.5–16?kHz) MR elastography for robust shear viscoelasticity model identification  

NASA Astrophysics Data System (ADS)

Changes in the viscoelastic parameters of soft biological tissues often correlate with progression of disease, trauma or injury, and response to treatment. Identifying the most appropriate viscoelastic model, then estimating and monitoring the corresponding parameters of that model can improve insight into the underlying tissue structural changes. MR Elastography (MRE) provides a quantitative method of measuring tissue viscoelasticity. In a previous study by the authors (Yasar et al 2013 Magn. Reson. Med. 70 479–89), a silicone-based phantom material was examined over the frequency range of 200?Hz–7.75?kHz using MRE, an unprecedented bandwidth at that time. Six viscoelastic models including four integer order models and two fractional order models, were fit to the wideband viscoelastic data (measured storage and loss moduli as a function of frequency). The ‘fractional Voigt’ model (spring and springpot in parallel) exhibited the best fit and was even able to fit the entire frequency band well when it was identified based only on a small portion of the band. This paper is an extension of that study with a wider frequency range from 500?Hz to 16?kHz. Furthermore, more fractional order viscoelastic models are added to the comparison pool. It is found that added complexity of the viscoelastic model provides only marginal improvement over the ‘fractional Voigt’ model. And, again, the fractional order models show significant improvement over integer order viscoelastic models that have as many or more fitting parameters.

Liu, Yifei; Yasar, Temel K.; Royston, Thomas J.

2014-12-01

235

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

236

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

237

Experimental results for a photonic time reversal processor for the adaptive control of an ultra wideband phased array antenna  

NASA Astrophysics Data System (ADS)

This paper describes a new concept for a photonic implementation of a time reversed RF antenna array beamforming system. The process does not require analog to digital conversion to implement and is therefore particularly suited for high bandwidth applications. Significantly, propagation distortion due to atmospheric effects, clutter, etc. is automatically accounted for with the time reversal process. The approach utilizes the reflection of an initial interrogation signal from off an extended target to precisely time match the radiating elements of the array so as to re-radiate signals precisely back to the target's location. The backscattered signal(s) from the desired location is captured by each antenna and used to modulate a pulsed laser. An electrooptic switch acts as a time gate to eliminate any unwanted signals such as those reflected from other targets whose range is different from that of the desired location resulting in a spatial null at that location. A chromatic dispersion processor is used to extract the exact array parameters of the received signal location. Hence, other than an approximate knowledge of the steering direction needed only to approximately establish the time gating, no knowledge of the target position is required, and hence no knowledge of the array element time delay is required. Target motion and/or array element jitter is automatically accounted for. Presented here are experimental results that demonstrate the ability of a photonic processor to perform the time-reversal operation on ultra-short electronic pulses.

Zmuda, Henry; Fanto, Michael; McEwen, Thomas

2008-04-01

238

Design and implementation of advanced algorithms for MIMO-UWB wireless communications  

Microsoft Academic Search

This paper describes the design and implementa- tion of low-complexity multiple-input multiple-output (MIMO) signal processing techniques suitable for ultra-wideband (UWB) wireless communications. It provides the general system concept, description of the measurement set-up and modular FPGA plat- form for test and verification of the proposed multiple antenna schemes under real air-interface environment. We validate the performance of selected spatial multiplexing

Emil Dimitrov; Claus Kupferschmidt; Thomas Kaiser; Juha Korpi; Risto Nordman; Antti Anttonen; Andrea Giorgetti; Marco Chiani

2011-01-01

239

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

240

Low power wireless ultra-wide band transmission of bio-signals  

NASA Astrophysics Data System (ADS)

The paper shows the design of microelectronic circuits composed of an oscillator, a modulator, a transmitter and an antenna. Prototype chips were recently fabricated and tested exploiting commercial 130 nm [1] and 180 nm [2,3] CMOS technologies. Detected signals have been measured using a commercial Ultra-Wide-Band amplifier connected to custom designed filters and a digital demodulator. Preliminary results are summarized along with some waveforms of the transmitted and received signals. A digital Synchronized On-Off Keying (S-OOK) was implemented to exploit the Ultra-Wide-Band transmission. In this way, each transmitted bit is coded with a S-OOK protocol. Wireless transmission capabilities of the system have been also evaluated within a one-meter distance. The chips fit a large variety of applications like spot radiation monitoring, punctual measurements of radiation in High-Energy Physics experiments or, since they have been characterized as low-power components, readout of the system for medical applications. These latter fields are those that we are investigating for in-vivo measurements on small animals. In more detail, if we refer to electromyographic, electrocardiographic or electroencephalographic signals [4], we need to handle very small signal amplitudes, of the order of tens of ?V, overwhelmed with a much higher (white) noise. In these cases the front-end of the readout circuit requires a so-called amplifier for instrumentation, here not described, to interface with metal-plate sensor's outputs such those used for electrocardiograms, to normal range of amplitude signals of the order of 1 V. We are also studying these circuits, to be also designed on a microelectronic device, without adding further details since these components are technically well known in the literature [5,6]. The main aim of this research is hence integrating all the described electronic components into a very small, low-powered, microelectronic circuit fully compatible with in-vivo applications.

Gabrielli, A.; Bastianini, S.; Crepaldi, M.; D'Amen, G.; Demarchi, D.; Lax, I.; Motto Ros, P.; Zoccoli, G.

2014-12-01

241

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

242

Channel models for wireless body area networks.  

PubMed

Wireless patient monitoring using wearable sensors is a promising application. This paper provides stochastic channel models for wireless body area network (WBAN) on the human body. Parameters of the channel models are extracted from measured channel transfer functions (CTFs) in a hospital room. Measured frequency bands are selected so as to include permissible bands for WBAN; ultra wideband (UWB), the industry, science and medical (ISM) bands, and wireless medical telemetry system (WMTS) bands. As channel models, both a path loss model and a power delay profile (PDP) model are considered. But, even though path loss models are derived for the all frequency bands, PDP model is only for the UWB band due to the highly frequency selectiveness of UWB channels. The parameters extracted from the measurement results are summarized for each channel model. PMID:19162968

Takizawa, Kenichi; Aoyagi, Akahiro; Takada, Jun-Ichi; Katayama, Norihiko; Yekeh, Kamya; Takehiko, Yazdandoost; Kohno, Kobayashi Ryuji

2008-01-01

243

[Wireless human body communication technology].  

PubMed

The Wireless Body Area Network (WBAN) is a key part of the wearable monitoring technologies, which has many communication technologies to choose from, like Bluetooth, ZigBee, Ultra Wideband, and Wireless Human Body Communication (WHBC). As for the WHBC developed in recent years, it is worthy to be further studied. The WHBC has a strong momentum of growth and a natural advantage in the formation of WBAN. In this paper, we first briefly describe the technical background of WHBC, then introduce theoretical model of human-channel communication and digital transmission machine based on human channel. And finally we analyze various of the interference of the WHBC and show the AFH (Adaptive Frequency Hopping) technology which can effectively deal with the interference. PMID:25868265

Sun, Lei; Zhang, Xiaojuan

2014-12-01

244

An ultra-wideband CMOS LNA for 3.1 to 10.6 GHz wireless receivers  

Microsoft Academic Search

A UWB 3.1 to 10.6 GHz LNA employing an input three-section band-pass Chebyshev filter is reported. Fabricated in a 0.18 ?m CMOS process, -10 dB over the band, a NF of 4 dB, and an IIP3 of -6.7 dBm while consuming the IC achieves a power gain of 9.3 dB with an input match of 9 mW.

A. Bevilacqua; A. M. Niknejad

2004-01-01

245

A low power ultra-wideband CMOS LNA for 3.1-10.6GHz wireless receivers  

Microsoft Academic Search

A CMOS 3.1-10.6GHz low power low noise amplifier utilizing a feedback technique is presented. The shunt and series-inductive peaking techniques have been used in the input and output stages to extend the 3-dB bandwidth of the LNA. To achieve wide and stable power and noise matching, the frequency dependent Miller multiplication factors, combined with a newly added parallel input inductor,

Kimia T. Ansari; Calvin Plett

2010-01-01

246

A 128Channel 6 mW Wireless Neural Recording IC With Spike Feature Extraction and UWB Transmitter  

Microsoft Academic Search

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

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

2009-01-01

247

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

E-print Network

[1, 2, 4]. 2 1.1. MODERN WIRELESS COMMUNICATION boards, solar panels and electricity meters could all be controlled wirelessly with the aim of creating a much more efficient energy supply system [6]. This increasing demand for and reliance upon... on Microwave Photonics (MWP)]. vi Contents List of Figures xi List of Tables xvii List of Acronyms xix 1 Introduction 1 1.1 Modern wireless communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 The wireless revolution...

Gordon, George S. D.

2013-11-12

248

A lightweight security protocol for ultra-low power ASIC implementation for wireless Implantable Medical Devices  

Microsoft Academic Search

The newest generation of Implantable Medical De- vices (IMDs) employs wireless communication with a nearby base station in order to provide better treatment and monitoring of the patients. However, a wireless connection opens a host of potential security threats to the privacy and safety of patients. This paper proposes a lightweight security protocol providing authentication and confidentiality to wireless energy-limited

Saied Hosseini-Khayat

2011-01-01

249

An Architecture for Wireless Simulation in NS2 Applied to Impulse-Radio Ultra-Wide Band Networks EPFL Technical Report LCA-REPORT-2006-128  

Microsoft Academic Search

We present an architecture for implementing a wireless physical layer in a packet-based network simulator. We integrate this architecture in the popular ns-2 network simulator and use it to implement an impulse-radio ultra-wide band (IR-UWB) physical layer. Contrary to the current wireless physical layer implementation of ns-2, in our case a packet is fully received by our physical layer before

Ruben Merz

250

60 GHz-band ultra-miniature monolithic T\\/R modules for multimedia wireless communication systems  

Microsoft Academic Search

60 GHz-band ultra-miniature FM\\/FSK transmitter\\/receiver modules utilizing a complete MMIC chip set including dielectrically stabilized VCO and local oscillator for wireless LANs and video signal transmission systems are reported. The 0.9 cc transmitter module exhibits 11.5 MHz\\/V modulation sensitivity and 10.2 dBm output power with -2.8 ppm\\/°C frequency stability. The receiver module has 9.2 dB downconversion gain and 5.4 dB

K. Ohata; T. Inoue; M. Funabashi; A. Inoue; Y. Takimoto; T. Kuwabara; S. Shinozaki; K. Maruhashi; K. Hosoya; H. Nagai

1996-01-01

251

Characterization of a CMOS sensing core for ultra-miniature wireless implantable temperature sensors with application to cryomedicine.  

PubMed

In effort to improve thermal control in minimally invasive cryosurgery, the concept of a miniature, wireless, implantable sensing unit has been developed recently. The sensing unit integrates a wireless power delivery mechanism, wireless communication means, and a sensing core-the subject matter of the current study. The current study presents a CMOS ultra-miniature PTAT temperature sensing core and focuses on design principles, fabrication of a proof-of-concept, and characterization in a cryogenic environment. For this purpose, a 100 ?m × 400 ?m sensing core prototype has been fabricated using a 130 nm CMOS process. The senor has shown to operate between -180°C and room temperature, to consume power of less than 1 ?W, and to have an uncertainty range of 1.4°C and non-linearity of 1.1%. Results of this study suggest that the sensing core is ready to be integrated in the sensing unit, where system integration is the subject matter of a parallel effort. PMID:25001173

Khairi, Ahmad; Thaokar, Chandrajit; Fedder, Gary; Paramesh, Jeyanandh; Rabin, Yoed

2014-09-01

252

208 IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, VOL. 11, NO. 5, MAY 2001 Novel Low-Cost Ultra-Wideband, Ultra-Short-Pulse  

E-print Network

generated using spark gaps [1]. Recently, a monocycle pulse generator has been developed using Schottky of this letter was arranged by Associate Editor Dr. Arvind Sharma. J. S. Lee is with Filtronic Solid State, Santa

Arslan, Hüseyin

253

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

254

A 315MHz Power-Gated Ultra Low Power Transceiver in 40nm CMOS for Wireless Sensor Network  

NASA Astrophysics Data System (ADS)

A 315MHz power-gated ultra low power transceiver for wireless sensor network is developed in 40nm CMOS. The developed transceiver features an injection-locked frequency multiplier for carrier generation and a power-gated low noise amplifier with current second-reuse technique for receiver front-end. The injection-locked frequency multiplier implements frequency multiplication by edge-combining and thereby achieves 11µW power consumption at 315MHz. The proposed low noise amplifier achieves the lowest power consumption of 8.4µW with 7.9dB noise figure and 20.5dB gain in state-of-the-art designs.

Liu, Lechang; Sakurai, Takayasu; Takamiya, Makoto

255

Wireless  

NSDL National Science Digital Library

Wireless Networking Mini-Tutorial (WKMN) [Macromedia Flash Player]http://www.wkmn.com/newsite/wireless.html#whatWi-Fi Alliancehttp://www.wi-fi.org/OpenSection/index.asp3Com: 802.11b Wireless LANs [pdf]http://www.3com.com/other/pdfs/infra/corpinfo/en_US/50307201.pdfInformation on BlueToothhttp://www.palowireless.com/bluetooth/e-week: WiFi Securityhttp://www.eweek.com/category2/0,1738,1591939,00.aspO'Reilly Network: Wireless Surveyinghttp://www.oreillynet.com/pub/a/wireless/2004/05/27/wirelessonPocketPC.htmlBitpipe: Wireless LAN White Papers [pdf]http://www.bitpipe.com/data/rlist?t=sys_10_34_4_2_np&sort_by=status&src=googleThe first website from WKMN (1) identifies the major types of wireless used today as Local Area Networks (LANs), Wide Area Networks (WANs) and Mobile Wireless, and Personal Area Networks. The WiFi Alliance, which certifies interoperability of IEEE 802.11 products in order "to promote them as the global, wireless LAN standard across all market segments" also gives an overview of WiFi, or Wireless Fidelity, on this second website (2). The IEEE 802.11 is the common standard used for LANs and is described more in this white paper from 3Com (3). The Bluetooth infrastructure, more common in Personal Area Networks, is described on this website (4 ). The current hot issue in the Wi-Fi world is security, which is discussed in this article from e-Week (5). Legal issues are also being raised, especially since the boundaries for wireless are unclear, which means people can survey for wireless networks without paying for access. This process is described in an article from the O'Reilly Network website (6). Finally, this last website (7) offers a number of white papers on wireless LAN.

256

Wideband VGAs Using a CMOS Transconductor in Triode region  

Microsoft Academic Search

Wideband variable gain amplifiers (VGAs) fabricated using 0.18 mum CMOS process are presented. A scheme with a CMOS triode transconductor is proposed to achieve linear-in-dB characteristics of VGAs for ultra wideband (UWB) systems. The implemented transmitter (TX) VGA shows a highly linear gain range of 28.4 dB (7 dB to -21.4 dB) and a bandwidth of 1200 MHz, while drawing

Hui Dong Lee; Kyung Ai Lee; Songcheol Hong

2006-01-01

257

PicoRadio Supports Ad Hoc Ultra-Low Power Wireless Networking  

Microsoft Academic Search

Technology advances have made it conceivable to build and deploy dense wireless networks of heterogeneous nodes collecting and disseminating wide ranges of environmental data. Applications of such sensor and monitoring networks include smart homes equipped with security, identification, and personalization systems; intelligent assembly systems; warehouse inventory control; interactive learning toys; and disaster mitigation. The opportunities emerging from this technology give

Jan M. Rabaey; M. Josie Ammer; Julio Leao da Silva Jr.; Danny Patel; Shad Roundy

2000-01-01

258

Wireless Ultra-Low Power Smart Data Acquisition System for Pressure Sensing in Medical Application  

Microsoft Academic Search

The development of a wireless sensor microsystems containing all the components of data acquisition system, such as sensors, signal-conditioning circuits, analog-digital converter, embedded microcontroller (MCU), and RF communication modules has become now the focus of attention in many biomedical applications. This paper discusses innovation circuits and system techniques for building advanced smart medical devices (SMD). Low power consumption and high

K. Arshak; E. Jafer

2006-01-01

259

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

E-print Network

Modern satellite, wireless communications, and radar systems often demand wideband performance for multi-channel and multi-function operations. Among these applications, phased array antennas play an important role. This dissertation covers two...

Tu, Wen-Hua

2009-05-15

260

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

261

A robust ultra-broad-band wireless communication system using SAW chirped delay lines  

Microsoft Academic Search

Design and performance of a low-cost wireless communication system for indoor and industrial environments are presented. The system is based on chirp-signal transmission to achieve a robust communication link. For the chirp expansion and compression, surface acoustic wave chirped delay lines fabricated from LiTaO3-X112rotY are used. Center frequency, bandwidth, and chirp rate are 348.8 MHz, 80 MHz, and ±40 MHz\\/?s,

Andreas Springer; Mario Huemer; Leonhard Reindl; Clemens C. W. Ruppel; Alfred Pohl; Franz Seifert; Wolfgang Gugler; Robert Weigel

1998-01-01

262

A robust ultra broadband wireless communication system using SAW chirped delay lines  

Microsoft Academic Search

Design and performance of SAW chirped delay lines on LiTaO3 -X112rotY for a wireless communication system are presented. Center frequency, bandwidth and chirp rate are 350 MHz, 80 MHz, and ±20 MHz\\/s, respectively. An optimized square-root weighting was chosen to reduce the sidelobes of the compressed pulse to -42 dB compared to the correlation peak. The chirp filters have been

A. Springer; A. Pohl; W. Gugler; M. Huemer; L. Reindl; C. C. W. Ruppel; F. Seifert; R. Weigel

1998-01-01

263

Ultra low-power sub-band acoustic echo cancellation for wireless headsets  

Microsoft Academic Search

Integrating voice-processing algorithms into headsets is a challenging task due to size and power constraints. As a result of the small size of these headsets, acoustic leakage between the closely located speaker and microphone is a common problem. To address this problem, an oversampled sub-band adaptive acoustic echo cancellation system is proposed and implemented on an ultra-low resource DSP system.

Julie Johnson; Etienne Cornu; Gary Choy; John Wdowiak

2004-01-01

264

Wideband radar phenomenology of forest stands  

Microsoft Academic Search

In this paper, experimental ultra wideband radar backscatter response of a forest stand for remote sensing using applications are presented. The radar signal is a a zero-mean pulse with a duration of 1.5 ns, and rise time of 0.1 ns occupying a bandwidth 3 GHz from 0.5 GHz-3.5 GHz. The transmitter pulse amplitude exceeds 240 V in a 50 ohm

E. D. Telpukhovskiy; V. P. Yakubov; V. L. Mironov; K. Sarabandi; G. M. Tsepelev

2003-01-01

265

An ultra-low energy microcontroller for Smart Dust wireless sensor networks  

Microsoft Academic Search

A 12pJ\\/instruction microcontroller with embedded SPAM designed specifically for use in mm3 wireless sensor nodes is described. It features highly independent subsystems for sensor sampling, transmission, and receiving that maximize the datapath sleep time as well as 100nW integrated oscillators with rapid power-cycling. Designed in 0.25?m technology, the 0.38mm2 core consumes 5.9?W from a 1V supply when running at 500kHz.

Brett A. Warneke; Kristofer S. J. Pister

2004-01-01

266

Wireless ultra-wide-band transmission prototype ASICs for low-power space and radiation applications  

NASA Astrophysics Data System (ADS)

The paper describes the design and the fabrication of a microelectronic circuit composed of a sensor, an oscillator, a modulator, a transmitter and an antenna. The chip embeds a custom radiation sensor, provided by the silicon foundry that has fabricated the prototypes, but in principle the entire system can read a general sensor, as long as a proper interface circuit is used. The natural application for this circuit is radiation monitoring but the low-power budget extends the applications to space where wireless readout circuits can be applied to any type of sensors, even if not radiation sensitive devices.

Gabrielli, A.; Crepaldi, M.; Demarchi, D.; Motto Ros, P.; Villani, G.

2014-11-01

267

Wideband tapped delay line channel model at 3.5 GHz for broadband fixed wireless access system as function of subscriber antenna height in suburban environment  

Microsoft Academic Search

This paper presents the results of measurements made to characterise the 3.5 GHz broadband fixed wireless access channel in a suburban environment, using a sectored base station antenna and a directional subscriber antenna. A tapped delay line channel impulse response model of the single-input single-output (SISO) channel is derived from the measurements. Previously, it has been reported that the delay

Chia Leong Hong; Ian J. Wassell; G. E. Athanasiadou; S. Greaves; M. Sellars

2003-01-01

268

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

269

Rapid Sensing of Underutilized, Wideband Spectrum Using the Random Demodulator  

E-print Network

efficiently use wireless spectrum. The so-called white-space devices are an exam- ple that utilize unused technologies which more efficiently utilize large swaths of spectrum. For example, cognitive radio and white-spaceRapid Sensing of Underutilized, Wideband Spectrum Using the Random Demodulator Andrew Harms1

Bajwa, Waheed U.

270

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

271

Radio frequency identification enabled wireless sensing for intelligent food logistics.  

PubMed

Future technologies and applications for the Internet of Things (IoT) will evolve the process of the food supply chain and create added value of business. Radio frequency identifications (RFIDs) and wireless sensor networks (WSNs) have been considered as the key technological enablers. Intelligent tags, powered by autonomous energy, are attached on objects, networked by short-range wireless links, allowing the physical parameters such as temperatures and humidities as well as the location information to seamlessly integrate with the enterprise information system over the Internet. In this paper, challenges, considerations and design examples are reviewed from system, implementation and application perspectives, particularly with focus on intelligent packaging and logistics for the fresh food tracking and monitoring service. An IoT platform with a two-layer network architecture is introduced consisting of an asymmetric tag-reader link (RFID layer) and an ad-hoc link between readers (WSN layer), which are further connected to the Internet via cellular or Wi-Fi. Then, we provide insights into the enabling technology of RFID with sensing capabilities. Passive, semi-passive and active RFID solutions are discussed. In particular, we describe ultra-wideband radio RFID which has been considered as one of the most promising techniques for ultra-low-power and low-cost wireless sensing. Finally, an example is provided in the form of an application in fresh food tracking services and corresponding field testing results. PMID:24797140

Zou, Zhuo; Chen, Qiang; Chen, Qing; Uysal, Ismail; Zheng, Lirong

2014-06-13

272

A UWB wireless capsule endoscopy device.  

PubMed

Wireless capsule endoscopy (WCE) presents many advantages over traditional wired endoscopic methods. The performance of WCE devices can be improved using high-frequency communication systems such as Impulse Radio-Ultra-Wideband (IR-UWB) to enable a high data rate transmission with low-power consumption. This paper presents the hardware implementation and experimental evaluation of a WCE device that uses IR-UWB signals in the frequency range of 3.5 GHz to 4.5 GHz to transmit image data from inside the body to a receiver placed outside the body. Key components of the IR-UWB transmitter, such as the narrow pulse generator and up-conversion based RF section are described in detail. This design employs a narrowband receiver in the WCE device to receive a control signal externally in order to control and improve the data transmission from the device in the body. The design and performance of a wideband implantable antenna that operates in the aforementioned frequency range is also described. The operation of the WCE device is demonstrated through a proof-of-concept experiment using meat. PMID:25571601

Thotahewa, Kasun M S; Redoute, Jean-Michel; Yuce, Mehmet Rasit

2014-01-01

273

An effective solution of wireless channel sounder and its channel modeling application  

Microsoft Academic Search

A real time wideband wireless channel sounder based on WCDMA system is introduced in this paper. After installing a baseband data acquisition device to the base station and some modifications on test UE, a real time wideband wireless channel sounder is established with fairly high performance and low cost comparing to commercial channel sounders. The time resolution of this sounder

Jiang Peigang; Wang Shaobo; Li Huajia

2004-01-01

274

Wideband ESM receiving systems. I  

Microsoft Academic Search

Three examples of wideband radar systems are discussed: (1) pulse compression, (2) frequency agile, and (3) multibeam. Consideration is given to wideband receiving systems, such as crystal video, acoustooptic, compressive (microscan), and digital IFM receivers.

C. B. Hofmann; A. R. Baron

1980-01-01

275

Wideband ESM receiving systems. I  

NASA Astrophysics Data System (ADS)

Three examples of wideband radar systems are discussed: (1) pulse compression, (2) frequency agile, and (3) multibeam. Consideration is given to wideband receiving systems, such as crystal video, acoustooptic, compressive (microscan), and digital IFM receivers.

Hofmann, C. B.; Baron, A. R.

1980-09-01

276

Wideband DS-CDMA for next-generation mobile communications systems  

Microsoft Academic Search

Wideband wireless access based on direct sequence code division multiple access aimed at third-generation mobile communications systems is reviewed. W-CDMA is designed to flexibly offer wideband services which cannot be provided by present cellular systems, with various data rates as high as 2 Mb\\/s. The important concept of W-CDMA is the introduction of intercell asynchronous operation and the pilot channel

Fumiyuki Adachi; Mamoru Sawahashi; Hirohito Suda

1998-01-01

277

Wide-band orthomode transducers  

Microsoft Academic Search

A summary of the results of a mainly experimental investigation into the development of wideband orthomode transducers (OMTs) is presented. It is shown that satisfactory performance for many applications is possible over bandwidths in excess of 2:1. The wideband return loss and cross-polarization behavior are given where the OMT used is measured in conjunction with a wideband corrugated horn. Two

Stephen J. Skinner; Graeme L. James

1991-01-01

278

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

279

Universal transmitter for wireless and optical access converged networks  

NASA Astrophysics Data System (ADS)

The integration of ultra-wideband (UWB)-over- ber into passive optical network (PON) is of great interest as it bene ts the high bandwidth capability from optical network technologies and the high exibility from wireless network technologies. The later can only be done with a reasonable cost when a universal optical transmitter, which is capable of generation both UWB and PON signals, is available. Direct modulation of semiconductor laser was demonstrated to be suitable for high bit-rate PON systems, however the generation of UWB signals by this technique is still challenging. Using the chirp properties of directly modulated semiconductor lasers, UWB signals are generated. Di erent UWB signal waveforms and polarities are obtained. The received electrical spectra conform to the requirements of indoor UWB systems.

Le, Quang T.; Küppers, Franko

2013-12-01

280

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

2014-12-01

281

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

282

Analysis of a multi-access scheme and asynchronous transmit-only UWB for wireless body area networks.  

PubMed

Ultra Wideband (UWB) has many favorable factors for use in a wireless body area network application. The major drawback is the high power consumption of an UWB receiver. One solution to address this problem is to use a transmit-only UWB sensor node. In this paper, we propose a multi-access scheme that is suitable for asynchronous transmit-only UWB wireless body area networks (UWB-WBAN). Each sensor attached on the patient under monitoring is assigned a unique number of UWB pulses per data bit. The number of UWB pulses assigned to the sensors is optimized to improve the bit error rate and system reliability. Simulation shows that through careful selection of the number of pulses for the sensors, it is possible to maintain almost similar bit error probability, regardless of the distance from the receiver. PMID:19964453

Keong, Ho Chee; Yuce, Mehmet R

2009-01-01

283

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

284

Novel Manufacturing Processes for Ultra-Low-Cost Paper-Based RFID Tags with Enhanced "Wireless Intelligence"  

E-print Network

PIREA RFID/Sensor Lab, Georgia Electronic Design Center School ofElectrical and Computer Engineering tags that can be integrated with batteries and sensors for wireless sensing, tracking and monitoring sensors and batteries to be mounted or embedded. A fast ink jet printing process can be used efficiently

Tentzeris, Manos

285

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 shockwave diode, which increases and sharpens the pulse even more.

McEwan, Thomas E. (Livermore, CA)

1993-01-01

286

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

287

Wideband plasmonic focusing metasurfaces  

NASA Astrophysics Data System (ADS)

We present a technique for designing wideband focusing metasurfaces. The proposed metasurface consists of unit cells of nanoparticle-based spatial phase shifters distributed over a planar surface. The topology of each spatial phase shifter is based on the design of plasmonic frequency selective surfaces. A true ab-initio design procedure for the proposed reflectarray is also proposed for the desired bandwidth and center frequency. A reflectarray for focusing the entire red spectrum (75 nm) is designed, with full-wave simulation results demonstrating desired focusing.

Saeidi, Chiya; Weide, Daniel van der

2014-08-01

288

An ultra low-power and traffic-adaptive medium access control protocol for wireless body area network.  

PubMed

Wireless Body Area Network (WBAN) consists of low-power, miniaturized, and autonomous wireless sensor nodes that enable physicians to remotely monitor vital signs of patients and provide real-time feedback with medical diagnosis and consultations. It is the most reliable and cheaper way to take care of patients suffering from chronic diseases such as asthma, diabetes and cardiovascular diseases. Some of the most important attributes of WBAN is low-power consumption and delay. This can be achieved by introducing flexible duty cycling techniques on the energy constraint sensor nodes. Stated otherwise, low duty cycle nodes should not receive frequent synchronization and control packets if they have no data to send/receive. In this paper, we introduce a Traffic-adaptive MAC protocol (TaMAC) by taking into account the traffic information of the sensor nodes. The protocol dynamically adjusts the duty cycle of the sensor nodes according to their traffic-patterns, thus solving the idle listening and overhearing problems. The traffic-patterns of all sensor nodes are organized and maintained by the coordinator. The TaMAC protocol is supported by a wakeup radio that is used to accommodate emergency and on-demand events in a reliable manner. The wakeup radio uses a separate control channel along with the data channel and therefore it has considerably low power consumption requirements. Analytical expressions are derived to analyze and compare the performance of the TaMAC protocol with the well-known beacon-enabled IEEE 802.15.4 MAC, WiseMAC, and SMAC protocols. The analytical derivations are further validated by simulation results. It is shown that the TaMAC protocol outperforms all other protocols in terms of power consumption and delay. PMID:20703634

Ullah, Sana; Kwak, Kyung Sup

2012-06-01

289

Wide-band orthomode transducers  

NASA Astrophysics Data System (ADS)

A summary of the results of a mainly experimental investigation into the development of wideband orthomode transducers (OMTs) is presented. It is shown that satisfactory performance for many applications is possible over bandwidths in excess of 2:1. The wideband return loss and cross-polarization behavior are given where the OMT used is measured in conjunction with a wideband corrugated horn. Two types of OMT are considered: one based on a finline technique and the other on a quad-ridged waveguide geometry. Overall, the latter design gives superior performance.

Skinner, Stephen J.; James, Graeme L.

1991-02-01

290

Wireless Technologies in Support of ISS Experimentation and Operations  

NASA Technical Reports Server (NTRS)

Presentation reviews: (1) Wireless Communications (a) Internal (b) External (2) RFID (Radio Frequency Identification) (a) Existing and R&D (3) Wireless Sensor Networks (a) Existing and R&D (4) Ultra-Wide Band (UWB) (a) R&D

Wagner, Raymond; Fink, Patrick

2012-01-01

291

A human body model for efficient numerical characterization of UWB signal propagation in wireless body area networks.  

PubMed

Wireless body area network (WBAN) is a new enabling system with promising applications in areas such as remote health monitoring and interpersonal communication. Reliable and optimum design of a WBAN system relies on a good understanding and in-depth studies of the wave propagation around a human body. However, the human body is a very complex structure and is computationally demanding to model. This paper aims to investigate the effects of the numerical model's structure complexity and feature details on the simulation results. Depending on the application, a simplified numerical model that meets desired simulation accuracy can be employed for efficient simulations. Measurements of ultra wideband (UWB) signal propagation along a human arm are performed and compared to the simulation results obtained with numerical arm models of different complexity levels. The influence of the arm shape and size, as well as tissue composition and complexity is investigated. PMID:21062677

Lim, Hooi Been; Baumann, Dirk; Li, Er-Ping

2011-03-01

292

Energy Efficiency of MIMO Transmission Strategies in Wireless Sensor Networks Huaiyu Dai, Liang Xiao, and Quan Zhou  

E-print Network

Energy Efficiency of MIMO Transmission Strategies in Wireless Sensor Networks Huaiyu Dai, Liang in the link adaptation study. Keywords: Cooperative MIMO, Energy Efficiency, MIMO Transmission, Mobile Agent, Sensor Network, Spectral Efficiency, Virtual MIMO, Wideband Regime. #12;Energy Efficiency of MIMO

Dai, Huaiyu

293

A New Wideband MIMO Channel Model for Simulating 5GHz Band Indoor WLANs  

Microsoft Academic Search

Considerable interest in the indoor applications of wireless local-area networks (WLANs) demands some powerful simulation methods of these systems. Proper modeling of the physical propagation channel is crucial in this context. A novel simulation method for indoor wideband multi-input multi-output (MIMO) channel at the operating frequency band of IEEE 802.11a, HIPERLAN\\/2, and the emerging IEEE 802.11n standards is presented in

Esrafil Jedari; Mahdi Golparvar Roozbahani; Amir Ahmad Shishegar; Ali Reza Enayati; Reza Alihemmati

2006-01-01

294

MIMO capacities for different antenna array structures based on double directional wide-band channel measurements  

Microsoft Academic Search

We present an approach for investigating the performance of generic multiple-input multiple-output (MIMO) wireless systems in a realistic way using wideband real-time propagation measurements of the double-directional radio channel. Applying a multidimensional high-resolution channel parameter estimation procedure the descriptive parameters for any relevant propagation path including the path weights, time-delay, Doppler shift and the propagation directions at both ends of

Dirk Hampicke; M. Landmann; C. Schneider; G. Sommerkorn; T. Thoma; T. Fugen; J. Maurer; W. Wiesbeck

2002-01-01

295

Multichannel Detection for Wideband Underwater  

Microsoft Academic Search

Direct-sequence CDMA is considered for future wideband mobile underwater acoustic networks, where a typical configuration may include several autonomous underwater vehicles operating within a few kilometers of a central receiver. Two receivers that utilize multichannel (array) processing of asynchronous multiuser signals are proposed: the symbol decision feedback (SDF) receiver and the chip hypothesis feedback (CHF) receiver. Both receivers use a

Acoustic CDMA Communications; Milica Stojanovic; Lee Freitag

296

Inter/Intra-Vehicle Wireless Communication file:///X:/www-docs/cse574-06/ftp/vehicular_wireless/index.html 1 of 16 5/9/2006 7:32 PM  

E-print Network

, Bluetooth, dedicated short range communication, ultra-wideband, ray optics, signal to noise ratio, omni of the emergency braking of a preceding vehicle, or the presence of an obstacle in the roadway. Such a network

Jain, Raj

297

Wideband beam patterns from sparse arrays  

SciTech Connect

Transient radiated fields due to impulsively excited apertures and aperture response due to incident impulsive waves has been the subject of considerable research in acoustics over the last decade. This research is also of importance to wideband radar. Medical ultrasound steered phased arrays use transmitted pulses consisting of from 1 to 3 cycles of a damped sinusoid, which is similar to certain radar systems. As will be shown, planar arrays using ultra-wide band pulses may be formed with very sparsely spaced elements. This makes feasible very high resolution, economical, and relatively simple, steered beam phased arrays. The resolution may be increased simply by moving the array elements further apart. Grating lobes due to aliasing are not formed when the elements are sparsely spaced. In a very sparse wide band array, element spacing effects the form, or signal shape in time, rather than the peak amplitude of the sidelobe structure. The number of elements in the aperture determines the peak sidelobe level which, in theory, may be decreased without limit. 13 refs., 7 figs.

Anderson, F. (Anderson (Forrest), Bernalillo, NM (USA)); Fullerton, L. (Time Domain Systems, Huntsville, AL (USA)); Christensen, W.; Kortegaard, B. (Los Alamos National Lab., NM (USA))

1990-01-12

298

Characterization of the bistable wideband optical filter on the basis of nonlinear 2D photonic crystal  

SciTech Connect

In our work, we investigated the wideband optical filter on the basis of nonlinear photonic crystal. The all-optical flip-flop using ultra-short pulses with duration lower than 200 fs is obtained in such filters. Here we pay special attention to the stability problem of the nonlinear element. To investigate this problem, the temporal response demonstrating the flip-flop have been computed within the certain range of the wavelengths as well as at different input power.

Guryev, I. V., E-mail: guryev@ieee.org; Sukhoivanov, I. A., E-mail: guryev@ieee.org; Andrade Lucio, J. A., E-mail: guryev@ieee.org; Manzano, O. Ibarra, E-mail: guryev@ieee.org; Rodriguez, E. Vargaz, E-mail: guryev@ieee.org; Gonzales, D. Claudio, E-mail: guryev@ieee.org; Chavez, R. I. Mata, E-mail: guryev@ieee.org; Gurieva, N. S., E-mail: guryev@ieee.org [University of Guanajuato, Engineering division (Mexico)

2014-05-15

299

An Undergraduate Research Experience: Wireless Propagation and Position Location in a Forest Environment  

NSDL National Science Digital Library

Over the past several years, the undergraduate curriculum at many universities has been evolving to incorporate laboratory exercises and research projects to reinforce and support traditional classroom lectures. In particular, involving undergraduates in meaningful research projects is a key to providing them with the hands-on activities students are demanding. Unfortunately, two areas in the electrical engineering curriculum are suffering from a lack of meaningful hands-on learning activities: electromagnetics and communications. At many universities, electromagnetics is taught as a highly theoretical, highly mathematical class with the goal of providing students a deep understanding of Maxwells equations. Students that complete such a course generally struggle when faced with applying Maxwells equations to real-world electromagnetics problems such as transmission lines, antenna design, or wireless propagation. Introductory communications courses may have laboratory components, however, involving students in an undergraduate research project is an excellent mechanism to supplement and reinforce the laboratory exercises. This paper presents a summer undergraduate research experience that involved characterizing ultra wideband wireless propagation and position location in a forest environment. Four undergraduate students were selected to participate in the research experience. All four students had taken the basic electromagnetics and communications courses, although only one had prior hands-on experience. Additionally, the use of impulse ultra-wideband signals represented a new wireless communication scheme that students had to master at the beginning of the research experience. After an initial training period, students were tasked with site selection, experimental design, recording measurements, analyzing data, and troubleshooting equipment failures. Although it is too early to assess the impact of the research experience on these students careers, the experience appears to have been a success. All four students reported a greater depth of understanding of the concepts taught in electromagnetics and communications courses. Additionally, students gained valuable experience in developing and carrying out field experiments sometimes in less than ideal conditions and as a result of this experience, some students expressed a desire to pursue a graduate degree. Designing this research project also provided several valuable lessons to the instructors which will aid in the further development of hands-on learning activities for electromagnetics and communications courses.

Anderson, Christopher

300

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

301

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

302

Constrained State Estimation for Individual Localization in Wireless Body Sensor Networks  

PubMed Central

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

303

A Framework for UWB-Based Communication and Location Tracking Systems for Wireless Sensor Networks  

PubMed Central

Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including Wireless Sensor Networks (WSN) with simultaneous data transmission and location tracking. The combination of location and data transmission is important in order to increase flexibility and reduce the cost and complexity of the system deployment. In this scenario, accuracy is not the only evaluation criteria, but also the amount of resources associated to the location service, as it has an impact not only on the location capacity of the system but also on the sensor data transmission capacity. Although several studies can be found in the literature addressing UWB-based localization, these studies mainly focus on distance estimation and position calculation algorithms. Practical aspects such as the design of the functional architecture, the procedure for the transmission of the associated information between the different elements of the system, and the need of tracking multiple terminals simultaneously in various application scenarios, are generally omitted. This paper provides a complete system level evaluation of a UWB-based communication and location system for Wireless Sensor Networks, including aspects such as UWB-based ranging, tracking algorithms, latency, target mobility and MAC layer design. With this purpose, a custom simulator has been developed, and results with real UWB equipment are presented too. PMID:22164120

Chóliz, Juan; Hernández, Ángela; Valdovinos, Antonio

2011-01-01

304

Handover considerations in VCO design for multistandard wireless receiver  

Microsoft Academic Search

This paper analyses handover scenario used in 3G standard and results are used to design and implement a reconfigurable voltage controlled oscillator (VCO) for multistandard wireless receiver. The third-generation (3G) standard has introduced hybrid wireless network for better use of resources. The typical example of hybrid network is integration of radio access technologies such as Wideband Code Division Multiple-Access (W-CDMA)

V. Vibhute; R. Veljanovski; J. Singh; A. Zayegh; A. Stojcevski

2004-01-01

305

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

306

Detection performance comparison for wideband and narrowband radar in noise  

Microsoft Academic Search

The detection performance of wideband radars in noise is better than that of the narrowband radars under some conditions, due to higher range resolution and less target return fluctuation. The detection probabilities of wideband and narrowband radars for the wideband non-fluctuation, Rayleigh and Ricean target models in white Gaussian noise are deduced. The detection curves show that the wideband radars

Fengzhou Dai; Penghui Wang; Hongwei Liu; Shunjun Wu

2010-01-01

307

Distribution of infrared light power for indoor broadband wireless communications  

Microsoft Academic Search

There has been a growing interest in using infrared light for broadband indoor wireless communications. There are two major limitations for establishing a wideband infrared communications link. The first and most important limit is the power requirements of such a link. The second important impairment is the intersymbol interference caused by multipath dispersion. We address the issue of designing an

M. R. Pakravan; M. Kavehrad

1995-01-01

308

Radio resource management in future wireless networks: requirements and limitations  

Microsoft Academic Search

Comparing market estimates for wireless personal communication and considering proposals for wideband multimedia services with the existing spectrum allocations for these types of systems show that spectrum resource management remains an important topic in the near and distant future. In this article the authors start by presenting a quite general formulation of the radio resource management problem where the three

Jens Zander

1997-01-01

309

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

310

Wideband RELAX and wideband CLEAN for aeroacoustic imaging  

NASA Astrophysics Data System (ADS)

Microphone arrays can be used for acoustic source localization and characterization in wind tunnel testing. In this paper, the wideband RELAX (WB-RELAX) and the wideband CLEAN (WB-CLEAN) algorithms are presented for aeroacoustic imaging using an acoustic array. WB-RELAX is a parametric approach that can be used efficiently for point source imaging without the sidelobe problems suffered by the delay-and-sum beamforming approaches. WB-CLEAN does not have sidelobe problems either, but it behaves more like a nonparametric approach and can be used for both point source and distributed source imaging. Moreover, neither of the algorithms suffers from the severe performance degradations encountered by the adaptive beamforming methods when the number of snapshots is small and/or the sources are highly correlated or coherent with each other. A two-step optimization procedure is used to implement the WB-RELAX and WB-CLEAN algorithms efficiently. The performance of WB-RELAX and WB-CLEAN is demonstrated by applying them to measured data obtained at the NASA Langley Quiet Flow Facility using a small aperture directional array (SADA). Somewhat surprisingly, using these approaches, not only were the parameters of the dominant source accurately determined, but a highly correlated multipath of the dominant source was also discovered.

Wang, Yanwei; Li, Jian; Stoica, Petre; Sheplak, Mark; Nishida, Toshikazu

2004-02-01

311

Rapid Wireless Capacitor Charging Using a Multi-Tapped Inductively-Coupled Secondary Coil  

E-print Network

This paper presents an inductive coupling system designed to wirelessly charge ultra-capacitors used as energy storage elements. Although ultra-capacitors offer the native ability to rapidly charge, it is shown that standard ...

Mercier, Patrick P.

312

Department of Electrical Engineering University of Southern California  

E-print Network

wireless and ultra wideband communications, signal processing, integrated circuits, and very large-scale. Her research interests include musical perception, cognition, visualization and quantitative analysis

Zhou, Chongwu

313

Ultra wideband photonic control of an adaptive phased array antenna  

NASA Astrophysics Data System (ADS)

This paper presents a new concept for a photonic implementation of a time reversed RF antenna array beamforming system. The process does not require analog to digital conversion to implement and is therefore particularly suited for high bandwidth applications. Significantly, propagation distortion due to atmospheric effects, clutter, etc. is automatically accounted for with the time reversal process. The approach utilizes the reflection of an initial interrogation signal from off an extended target to precisely time match the radiating elements of the array so as to re-radiate signals precisely back to the target's location. The backscattered signal(s) from the desired location is captured by each antenna and used to modulate a pulsed laser. An electrooptic switch acts as a time gate to eliminate any unwanted signals such as those reflected from other targets whose range is different from that of the desired location resulting in a spatial null at that location. A chromatic dispersion processor is used to extract the exact array parameters of the received signal location. Hence, other than an approximate knowledge of the steering direction needed only to approximately establish the time gating, no knowledge of the target position is required, and hence no knowledge of the array element time delay is required. Target motion and/or array element jitter is automatically accounted for. This paper presents the preliminary study of the photonic processor, analytical justification, and simulated results. The technology has a broad range of applications including aerospace and defense and in medical imaging.

Cox, Joseph L.; Zmuda, Henry; Li, Jian; Sforza, Pasquale M.

2006-05-01

314

Ultra wideband indoor channel modeling for personal area networking  

Microsoft Academic Search

This paper investigates the Line of Sight (LOS) path loss characteristics of the UWB channel by explicitly focusing on a very short range of 1¿5 m. A vector network analyzer was used to measure the channel transfer function in the frequency band of 6¿8 GHz. It has been observed that the published path loss models for UWB communications report a

Ranjan Bose

2006-01-01

315

Capacity Bounds for an Ultra-Wideband Channel Model  

Microsoft Academic Search

There is an ongoing effort by the IEEE 802.15.3a subcommittee to reach a UWB personal area network standard. We estimate the achievable rates for such networks using a channel model spec- ified by the same group. The analysis of this chan- nel model is of interest in light of recent information- theoretic work on multipath fading channels which show that

Erdal Arõkan

316

Capacity bounds for an ultra-wideband channel model  

Microsoft Academic Search

There is an ongoing effort by the IEEE 802.15.3a subcommittee to reach a UWB personal area network standard. We estimate the achievable rates for such networks using a channel model specified by the same group. The analysis of this channel model is of interest in light of recent information-theoretic work on multipath fading channels which show that in order to

Erdal Arikan

2004-01-01

317

Ultra-wideband radar target modeling using triangular patch model  

Microsoft Academic Search

To understand the UWB radar system, target scattering performance must be studied. As a widely used model in time domain electromagnetics triangular patch model (TPM) is employed to simulate UWB radar targets. But when the scattered fields are treated, singular points would occur of TPM. The singularity analysis is carried out of TPM and a method is proposed to deal

Shi-Wei Dong; Wei Ma; Hong-Tai Zhang; Le-De Qiu

2008-01-01

318

Signal Generation for FMCW Ultra-Wideband Radar  

E-print Network

Ohm N=N0 F0=Freq_0 VCO_Freq=k0*_v 1 fre q VCO . v co n - N. VCO tu ne d N V_1Tone SRC4 Freq=Fref V=(1*exp(-j*pi/2)) V Figure 3.4-ADS Design for PLL The simulation is carried out to generate a 10 GHz RF signal that is phase locked... components equally spaced about the peak indicates that it is coming from amplitude modulation. 43 6.7 6.71 6.72 6.73 6.74 6.75 x 107 5 10 15 20 25 30 35 40 45 Beat Frequency at 67.22 MHz; Delay 3.425 us; Hanning window applied Am pl itu de [d B...

Patel, Aqsa Ejaz

2009-01-01

319

75 FR 62476 - Ultra-Wideband Transmission Systems  

Federal Register 2010, 2011, 2012, 2013, 2014

...Systems proceeding and thus provides certainty for the continued development of UWB equipment, including ground penetrating radars for underground imaging, through wall imaging systems, short- range high capacity data links, and other applications....

2010-10-12

320

Transmission and Reception by Ultra-Wideband (UWB) Antennas  

Microsoft Academic Search

Broadband antennas are very useful in many applications because they operate over a wide range of frequencies. The objective of this paper is to study the transient responses of various well-known antennas over broad frequency ranges. As such, the phase responses of these antennas as a function of frequency are of great interest. In the ensuing analysis, each antenna is

Debalina Ghosh; Arijit de; Mary Taylor; Tapan Sarkar; Michael Wicks; Eric Mokole

2006-01-01

321

Ultra-wideband polarimetric imaging of corner reflectors in foliage  

Microsoft Academic Search

An ultrawideband imaging radar was developed. It is a highly mobile, ground-based system capable of 2D and 3D imaging at very close ranges to a synthetic aperture. The radar is fully coherent over two bandwidths (0.1 to 2 GHz and 2 to 18 GHz) and is being used for target and for foliage penetration measurements. The emphasis of the program

D. J. Blejer; S. M. Scarborough; C. E. Frost; H. R. Catalan; K. H. McCoin; J. Roman; D. M. Mukai

1992-01-01

322

Ultra wideband horn antenna for microwave imaging application  

Microsoft Academic Search

Recently, high-contrast and high-resolution microwave imaging has been extensively studied in the detection of early breast cancer, This method is based on the contrast in electrical properties of healthy fatty breast tissues and malignant tissues. In this paper we design a new TEM double-ridged horn antenna for microwave imaging application. Proposed antenna is simulated with two commercially available packages, namely

Hana Amjadi; Farzad Tavakkol Hamedani

2011-01-01

323

Microwave imaging for ultra-wideband antenna based cancer detection   

E-print Network

Breast cancer is one of the most widespread types of cancer in the world. The key factor in treatment is to reliably diagnose the cancer in the early stages. Moreover, currently used clinical diagnostic methods, such as ...

Zhang, Haoyu

2015-06-29

324

Ultra wideband antenna array processing under spatial aliasing  

E-print Network

to estimate the transmitted data signal and the DOA of each source. In the sequel, a subspace-based algorithm is developed and the prob- lem of order estimation is discussed. The adopted signaling framework assumes a subband hopping transmission in order...

Shapoury, Alireza

2009-05-15

325

Ultra wideband linear horn array antenna with slant polarization  

Microsoft Academic Search

A design of linear 8-element horn array antenna with 45°-slant polarization operating in octave bandwidth (4...8 GHz) is presented. The array antenna is characterized by sector type radiation patterns with gain ranging from 14 dB (at low frequency) to 18 dB (at high frequency) and side lobe levels less than -12dB. Wide bandwidth, slant polarization and relatively simple construction were

F. F. Dubrovka; S. Y. Martynyuk; P. Ya. Stepanenko; V. M. Tereshchenko; V. V. Marchenko

2005-01-01

326

Design of a Practical Scheme for Ultra Wideband Communication  

E-print Network

of the message. We consider schemes that are straightforward to implement in practical systems and propose two parts of the DHTR system on an FPGA prototype board. We propose two hardware architectures for detection-Jan van der Veen Circuit & Systems, Department of Electrical Engineering Delft University of Technology

van der Veen, Alle-Jan

327

Fractal-based wideband invisibility cloak  

NASA Astrophysics Data System (ADS)

A wideband invisibility cloak (IC) at microwave frequencies is described. Using fractal resonators in closely spaced (sub wavelength) arrays as a minimal number of cylindrical layers (rings), the IC demonstrates that it is physically possible to attain a `see through' cloaking device with: (a) wideband coverage; (b) simple and attainable fabrication; (c) high fidelity emulation of the free path; (d) minimal side scattering; (d) a near absence of shadowing in the scattering. Although not a practical device, this fractal-enabled technology demonstrator opens up new opportunities for diverted-image (DI) technology and use of fractals in wideband optical, infrared, and microwave applications.

Cohen, Nathan; Okoro, Obinna; Earle, Dan; Salkind, Phil; Unger, Barry; Yen, Sean; McHugh, Daniel; Polterzycki, Stefan; Shelman-Cohen, A. J.

2015-03-01

328

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

329

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

330

SECURING WIRELESS SECURING WIRELESS  

E-print Network

Network Security: 802.11, Bluetooth and Handheld Devices, in 2002. This guide assists organizations Bluetooth technology and wireless handheld devices such as text messaging devices, PDAs, and smart phones Special Publication (SP) 800-48, Wireless Network Security: 802.11, Bluetooth and Handheld Devices

331

Fiber wireless networks  

NASA Astrophysics Data System (ADS)

Broadband wireless networks based on a number of new frequency windows at higher microwave and millimeter-wave frequencies have been actively pursued to provide ultra-high bandwidth services over a wireless networks. These networks will have a large number of antenna base-stations with high throughput. Significant reductions in antenna base-station complexity can be achieved if most of the signal routing and switching functions centralized at a central office in the network. In such a network, fiber feed networks can be effectively deployed to provide high bandwidth interconnections between multiple antenna base-stations and the central office. With wavelength division multiplexing, efficient optical fiber feed network architectures could be realised to provide interconnection to a large number of antenna base-stations. In this paper, we present an over view of our recent research into system technologies for fiber wireless networks.

Nirmalathas, A.; Bakaul, M.; Lim, C.; Novak, D.; Waterhouse, R.

2005-11-01

332

Wideband Timing of Millisecond Pulsars  

NASA Astrophysics Data System (ADS)

The use of backend instrumentation capable of real-time coherent dedispersion of relatively large fractional bandwidths has become commonplace in pulsar astronomy. However, along with the desired increase in sensitivity to pulsars' broadband signals, a larger instantaneous bandwidth brings a number of potentially aggravating effects that can lead to degraded timing precision. In the case of high-precision timing experiments, such as the one being carried out by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), subtle effects such as unmodeled intrinsic profile evolution with frequency, interstellar scattering, and dispersion measure variation are potentially capable of reducing the experiment's sensitivity to a gravitational wave signal. In order to account for some of these complications associated with wideband observations, we augmented the traditional algorithm by which the fundamental timing quantities are measured. Our new measurement algorithm accommodates an arbitrary two-dimensional model ``portrait'' of a pulsar's total intensity as a function of observing frequency and rotational phase, and simultaneously determines the time-of-arrival (TOA), the dispersion measure (DM), and per-frequency-channel amplitudes that account for interstellar scintillation. Our publicly available python code incorporates a Gaussian-component modeling routine that allows for independent component evolution with frequency, a ``fiducial component'', and the inclusion of scattering. Here, we will present results from the application of our wideband measurement scheme to the suite of NANOGrav millisecond pulsars, which aimed to determine the level at which the experiment is being harmed by unmodeled profile evolution. We have found thus far, and expect to continue to find, that our new measurements are at least as good as those from traditional techniques. At a minimum, by largely reducing the volume of TOAs we will decrease the computational demand associated with probing posterior distributions in the search for gravitational waves. The development of this algorithm is well-motivated by the promise of even larger fractional bandwidth receiver systems in the future of pulsar astronomy.

Pennucci, Timothy; Demorest, Paul; Ransom, Scott M.; North American Nanohertz ObservatoryGravitational Waves (Nanograv)

2015-01-01

333

Ultra Reliability  

NASA Technical Reports Server (NTRS)

This viewgraph presentation gives a general overview of NASA's ultra reliability areas. The contents include: 1) Objectives; 2) Approach; 3) Ultra Reliability Areas; 4) Plan Overview; 5) Work Flows; and 6) Customers.

Napala, Phil; Barnes, Charles; Shapiro, Andrew A.

2004-01-01

334

Quasi-orthogonal wideband radar waveforms based on chaotic systems  

E-print Network

With the development of A/D converters possessing sufficiently high sampling rates, it is now feasible to use arbitrary, wideband waveforms in radar applications. Large sets of quasi-orthogonal, wideband waveforms can be ...

Willsey, Matt (Matt S.)

2007-01-01

335

Digitally-Assisted Mixed-Signal Wideband Compressive Sensing  

E-print Network

Digitizing wideband signals requires very demanding analog-to-digital conversion (ADC) speed and resolution specifications. In this dissertation, a mixed-signal parallel compressive sensing system is proposed to realize the sensing of wideband...

Yu, Zhuizhuan

2012-07-16

336

Centralized Collaborative Compressed Sensing of Wideband Spectrum for Cognitive Radios  

E-print Network

1 Centralized Collaborative Compressed Sensing of Wideband Spectrum for Cognitive Radios Hessam technique for cognitive radio systems which combines algebraic tools and compressive sampling techniques, spectrum sensing, cognitive radio, distri- bution discontinuities, algebraic detection, wideband. I

Paris-Sud XI, Université de

337

Low Power Filtering Techniques for Wideband and Wireless Applications  

E-print Network

in deep submicron technologies. Thirdly, a 20MHz, 68dB dynamic range active RC filter is presented. This filter is designed for a ten bit continuous time sigma delta ADC architecture developed specifically for fine-line CMOS technologies. Inverter based...

Gambhir, Manisha

2010-10-12

338

WIDEBAND SLOT AND PRINTED ANTENNAS ATEF Z. ELSHERBENI  

E-print Network

WIDEBAND SLOT AND PRINTED ANTENNAS ATEF Z. ELSHERBENI ABDELNASSER A. ELDEK CHARLES E. SMITH Center. INTRODUCTION Wideband antenna elements are essential for providing wideband scanning array antennas in industry anten- na systems. Because element size is a critical parameter in determining the scan angle in antenna

Elsherbeni, Atef Z.

339

Multi-antenna compressed wideband spectrum sensing for cognitive radio  

Microsoft Academic Search

This paper proposes a novel wideband spectrum sensing (WSS) scheme, termed multi-antenna compressed wide- band spectrum sensing (MCWSS) scheme, which utilizes com- pressed sensing (CS) to reduce the extremely high sampling rate of wideband signal. Although there are studies on compressed wideband spectrum sensing, they only focus on single antenna signal. Since multi-antenna technology can enhance the detection performance, this

Xianjun Yang; Qimei Cui; Rui Yang; Xiaofeng Tao; Xin Guo

2011-01-01

340

Wideband digital Quadrature Transformation based on perfect reconstruction filter banks  

Microsoft Academic Search

Quadrature Transformation based on Hilbert transform method to wideband signal is not suited to engineering application because the group delay can make severe aliasing. Wideband digital quadrature transformation based on perfect reconstruction filter banks is put forward in this paper. The wideband signal is divided into sub-band signals by analysis filter bank, then let the negative parts of the output

Xiaohong Huang; Zhenmiao Deng

2011-01-01

341

Narrowband to wideband conversion of speech using GMM based transformation  

Microsoft Academic Search

Reconstruction of wideband speech from its narrowband version is an attractive issue, since it can enhance the speech quality without modifying the existing communication networks. This paper proposes a new recovery method of wideband speech from narrowband speech. In the proposed method, the narrowband spectral envelope of input speech is transformed to a wideband spectral envelope based on the Gaussian

Kun-Youl Park; Hyung Soon Kim

2000-01-01

342

30 pJ/b, 67 Mbps, Centimeter-to-Meter Range Data Telemetry With an IR-UWB Wireless Link.  

PubMed

This paper reports an energy-efficient, impulse radio ultra wideband (IR-UWB) wireless link operating in 3-5 GHz for data telemetry over centimeter-to-meter range distances at rates extended to tens of Mbps. The link comprises an all-digital, integrated transmitter (TX) fabricated in 90 nm 1P/9M CMOS that incorporates a waveform-synthesis pulse generator and a timing generator for on-off-keying (OOK) pulse modulation and phase scrambling. The link also incorporates an energy-detection receiver (RX) realized with commercial off-the-shelf (COTS) components that performs radio-frequency (RF) filtering, amplification, logarithmic power detection for data demodulation and automatic level control for robust operation in the presence of distance variations. Employing a miniaturized, UWB, chip antenna for the TX and RX, wireless transmission of pseudo-random binary sequence (PRBS) data at rates up to 50 Mbps over 10 cm-1 m is shown. Further, employing a high-gain horn antenna for the RX, wireless transmission of PRBS data at rates up to 67 Mbps over 50 cm-4 m is shown with a TX energy consumption of 30 pJ/b (i.e., power consumption of 2 mW) from 1.2 V. The measured bit error rate (BER) in both cases is . Results from wireless recording of the background current of a carbon-fiber microelectrode (CFM) in one fast-scan cyclic voltammetry (FSCV) scan using the IR-UWB link are also included, exhibiting excellent match with those obtained from a conventional frequency-shift-keyed (FSK) link at  ? 433 MHz. PMID:25134088

Ebrazeh, Ali; Mohseni, Pedram

2014-08-12

343

Channelization architecture for wide-band slow light in atomic vapors  

E-print Network

We propose a ``channelization'' architecture to achieve wide-band electromagnetically induced transparency (EIT) and ultra-slow light propagation in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong, resonant ``pump'' laser on the atomic medium, which allows slow and unattenuated propagation of a weaker ``signal'' beam, but only when a two-photon resonance condition is satisfied. Our wideband architecture is accomplished by dispersing a wideband signal spatially, transverse to the propagation direction, prior to entering the atomic cell. When particular Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic field with a linear gradient such that the two-photon resonance condition is satisfied for each individual frequency component. Because slow light is a group velocity effect, utilizing differential phase shifts across the spectrum of a light pulse, one must then introduce a slight mismatch from perfect resonance to induce a delay. We present a model which accounts for diffusion of the atoms in the varying magnetic field as well as interaction with levels outside the ideal three-level system on which EIT is based. We find the maximum delay-bandwidth product decreases with bandwidth, and that delay-bandwidth product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a large improvement over the ~1 MHz bandwidths in conventional slow light systems and could be of use in signal processing applications.

Zachary Dutton; Mark Bashkansky; Michael Steiner; John Reintjes

2005-10-20

344

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

345

Optimization of data coils in a multiband wireless link for neuroprosthetic implantable devices.  

PubMed

We have presented the design methodology along with detailed simulation and measurement results for optimizing a multiband transcutaneous wireless link for high-performance implantable neuroprosthetic devices. We have utilized three individual carrier signals and coil/antenna pairs for power transmission, forward data transmission from outside into the body, and back telemetry in the opposite direction. Power is transmitted at 13.56 MHz through a pair of printed spiral coils (PSCs) facing each other. Two different designs have been evaluated for forward data coils, both of which help to minimize power carrier interference in the received data carrier. One is a pair of perpendicular coils that are wound across the diameter of the power PSCs. The other design is a pair of planar figure-8 coils that are in the same plane as the power PSCs. We have compared the robustness of each design against horizontal misalignments and rotations in different directions. Simulation and measurements are also conducted on a miniature spiral antenna, designed to operate with impulse-radio ultra-wideband (IR-UWB) circuitry for back telemetry. PMID:21918679

Uei-Ming Jow; Ghovanloo, M

2010-10-01

346

Optimization of Data Coils in a Multiband Wireless Link for Neuroprosthetic Implantable Devices  

PubMed Central

We have presented the design methodology along with detailed simulation and measurement results for optimizing a multiband transcutaneous wireless link for high-performance implantable neuroprosthetic devices. We have utilized three individual carrier signals and coil/antenna pairs for power transmission, forward data transmission from outside into the body, and back telemetry in the opposite direction. Power is transmitted at 13.56 MHz through a pair of printed spiral coils (PSCs) facing each other. Two different designs have been evaluated for forward data coils, both of which help to minimize power carrier interference in the received data carrier. One is a pair of perpendicular coils that are wound across the diameter of the power PSCs. The other design is a pair of planar figure-8 coils that are in the same plane as the power PSCs. We have compared the robustness of each design against horizontal misalignments and rotations in different directions. Simulation and measurements are also conducted on a miniature spiral antenna, designed to operate with impulse-radio ultra-wideband (IR-UWB) circuitry for back telemetry. PMID:21918679

Jow, Uei-Ming; Ghovanloo, Maysam

2011-01-01

347

Challenge: Ultra-Low-Power Energy-Harvesting Active Networked Tags (EnHANTs)  

E-print Network

]@ee.columbia.edu danr@cs.columbia.edu, [wangx, gil]@ee.columbia.edu ABSTRACT This paper presents the design challenges be attached to objects that are traditionally not networked (e.g., books, clothing, and produce), thereby, ultra-wideband (UWB) circuit design, and organic electronic harvesting techniques will enable

Zussman, Gil

348

Channel characterization for indoor wireless communications at 21.6 GHz and 37.2 GHz  

Microsoft Academic Search

This paper presents results of narrowband and wideband measurements of the indoor wireless channel at 21.6 GHz and 37.2 GHz. Narrowband measurements with antenna diversity were carried out using a modified Spectrum Analyzer operating as a two channel receiver. With this arrangement, two different environments were considered and in each between 10 and 20 measurements were taken. Average cumulative distribution

G. Kalivas; M. El-Tanaiiy; S. Mahmoud

1993-01-01

349

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 3, 2004 5 A Multiresonant Single-Element  

E-print Network

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 3, 2004 5 A Multiresonant Single-Element Wideband Slot Antenna Nader Behdad, Student Member, IEEE and Kamal Sarabandi, Fellow, IEEE Abstract--A new be chosen such that the overall bandwidth of the antenna is drastically increased. By using this technique

Sarabandi, Kamal

350

Distributed Algorithms for Multipath Routing in Full-Duplex Wireless Networks Arizona State University  

E-print Network

competitions and constraints. We first propose a collision-free full-duplex broadcast MAC and prove its, unlike prior work [9], supports wideband and high power systems. In theory, this new design has in wireless communication research during the last decades. In this paper, we concentrate on the cross

Xue, Guoliang

351

Miniaturized UHF planar antenna, for wireless indoor systems  

Microsoft Academic Search

In this paper a miniaturized Ultra High Frequency planar microstrip antenna is presented, which can be used in wireless indoor systems, such as on wall receivers, control units etc. The aim of this project was to make a miniaturized antenna for an indoor wireless receiver, operating at 868MHz. The main challenge for designing such an antenna model was the limitation

A. Babar; L. Ukkonen; M. Soini; L. Sydanheimo

2009-01-01

352

Wideband radar micro-doppler applications  

NASA Astrophysics Data System (ADS)

Wideband radar provides a significant improvement over traditional narrowband radars for micro-Doppler analysis because the high bandwidth can be used to separate many of the signals in range, allowing a simpler decomposition of the micro-Doppler signals. Recent wideband radar work has focused on micro-Doppler, but there is a point where the narrowband approach used to analyze the micro-Doppler signals breaks down. The effect is shown to be independent of frequency, but the error relative to the bandwidth is shown to be inversely proportional to the frequency and proportional to the velocity of the subject. This error can create a smearing effect in the observed Doppler if it is not corrected, leading to reduced signal-to-noise and the appearance of more diffuse targets in Doppler space. In range-space, wideband data can also break the subject into several range bins, affecting the observed signal to noise ratio. The possible applications of wideband micro-Doppler radar are also shown, including the separation of arm movement from human motion which implies that the arms are not encumbered.

Tahmoush, Dave

2013-05-01

353

Wideband acoustic communications dispelling narrowband myths  

Microsoft Academic Search

Robust synchronisation is a fundamental requirement for any wideband acoustic communication system. It is shown that the temporal scaling influence of acoustic Doppler arising from platform motion and path length fluctuations between ray arrivals plays a significant role in high and low data rate acoustic system performance. Poor channel time coherence invariably leads to a complex synchronisation problem; an area

J. J. Davies; S. A. Pointer; S. M. Dunn

2000-01-01

354

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

355

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

356

WIDEBAND MIMO MEASUREMENTS OF OUTDOOR NLOS CHANNELS  

E-print Network

communication; wideband channel sounder; mul- tipath delay profile; multiple-input-multiple-output channel capacity INTRODUCTION Multiple-input multiple-output (MIMO) communication systems with multiple antennas to simultaneously transmit multiple pseudo-random signals. Multiple receivers then receive the transmitted signals

Yang, Yaoqing "Lamar"

357

Wideband radar for airborne minefield detection  

Microsoft Academic Search

Ground Penetrating Radar (GPR) has been applied for several years to the problem of detecting both antipersonnel and anti-tank landmines. RDECOM CERDEC NVESD is developing an airborne wideband GPR sensor for the detection of minefields including surface and buried mines. In this paper, we describe the as-built system, data and image processing techniques to generate imagery, and current issues with

William W. Clark; Brian Burns; Gary Dorff; Brian Plasky; George Moussally; Mehrdad Soumekh

2006-01-01

358

Wideband CDMA Scheme for Multimedia Applications  

Microsoft Academic Search

The detection of the wideband code division multiple access (WCDMA) signal at the mobile using a new blind adaptive hybrid approach in the multiple-input multiple-output (MIMO) scenario is taken up. A two step method with only the knowledge of the spreading code of interest and the discard prefix (DP) assumption is proposed. This uses a higher order statistical (HOS) approach

E. Gopalakrishna Sarma; Sakuntala S. Pillai

2007-01-01

359

R. A. Scholtz University of Southern California UltRa Lab Ultra-Wideband Radio  

E-print Network

OneWayAttenuation(dB) Kevlar Sheet Polyethylene Paper Towel (Dry) Fiberglass Insul. concrete block painted 2x6 board 3/4"plywood 3/4" pine board wet paper towel glass drywall asphalt shingle kevlar, polystyrene dry paper to

Southern California, University of

360

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

361

Design of novel on-chip antennas with multi-band for wireless sensor networks  

Microsoft Academic Search

This paper presents a novel on-chip antenna with quintuple band so that it will be able to operate in the ultra wideband (UWB). The antenna consists of two trapezoidal slots which are symmetrical in the patch with coaxial feeding. The two types of substrate we have investigated for antenna design are the HRS and Pyrex glass wafers. The possibility of

Dong H. Park

2008-01-01

362

The ERTS wideband image communication system.  

NASA Technical Reports Server (NTRS)

The ERTS payload includes a three camera return beam vidicon (RBV) television system and a four channel multispectral scanner system (MSS). The communications system described includes spacecraft wideband equipment plus unique payload processing equipment located at three NASA tracking stations. The RBV information, transmitted as analog FM with a baseband response of dc to 3.2 MHz, is telemetered, processed and recorded on a wideband video recorder. The MSS data, consisting of 24 analog sensor outputs, is digitized and encoded as 15 megabit per second PCM. The MSS data is then transmitted as analog FM, demultiplexed, and recorded on a 25 channel recorder. It is shown that bit error rate is an excellent indicator of MSS link performance while signal-to-noise ratio and distortion vs frequency adequately define RBV link performance.

Pandelides, J.; Popowski, W. J.; Vanvleet, R. N.

1972-01-01

363

Wideband Hyperspectral Imaging for Space Situational Awareness  

Microsoft Academic Search

Wideband hyperspectral imaging (WHSI) systems collect simultaneous spectral and spatial imagery across a broad spectrum that includes the visible\\/near infrared (VNIR), short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR) regimes. These passive optical systems capture reflected sunlight and thermal emissions from targets enabling the characterization of surface material, thermal properties, propellants, and gaseous emissions when targets are sunlit

Ian S. Robinson; A. Klier

2006-01-01

364

Wideband radar for airborne minefield detection  

NASA Astrophysics Data System (ADS)

Ground Penetrating Radar (GPR) has been applied for several years to the problem of detecting both antipersonnel and anti-tank landmines. RDECOM CERDEC NVESD is developing an airborne wideband GPR sensor for the detection of minefields including surface and buried mines. In this paper, we describe the as-built system, data and image processing techniques to generate imagery, and current issues with this type of radar. Further, we will display images from a recent field test.

Clark, William W.; Burns, Brian; Dorff, Gary; Plasky, Brian; Moussally, George; Soumekh, Mehrdad

2006-05-01

365

Design of a Wideband Radio Telescope  

Microsoft Academic Search

A wideband Radio Telescope is being designed for use in the Goldstone Apple Valley Radio Telescope program. It uses an existing 34-meter antenna retrofitted with a tertiary offset mirror placed at the apex of the main reflector. It can be rotated to use two feeds that cover the 1.2 to 14 GHz band. The feed for 4.0 to 14.0 GHz

W. A. Imbriale; S. Weinreb; H. Mani

2007-01-01

366

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

367

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

368

4220 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 8, NO. 8, AUGUST 2009 An Empirical Model for Dual-Diversity Reception  

E-print Network

and distribution of users, and the base station and remote terminal antenna patterns can be used to estimate for Dual-Diversity Reception over Fixed Wireless Channels in Suburban Macrocell Environments David G to residences (wideband systems) or to supply automated meter reading and related supervisory control and data

Michelson, David G.

369

A wideband spiral antenna for ingestible capsule endoscope systems: experimental results in a human phantom and a pig.  

PubMed

This paper presents the design of a wideband spiral antenna for ingestible capsule endoscope systems and a comparison between the experimental results in a human phantom and a pig under general anesthesia. As wireless capsule endoscope systems transmit real-time internal biological image data at a high resolution to external receivers and because they operate in the human body, a small wideband antenna is required. To incorporate these properties, a thick-arm spiral structure is applied to the designed antenna. To make practical and efficient use of antennas inside the human body, which is composed of a high dielectric and lossy material, the resonance characteristics and radiation patterns were evaluated through a measurement setup using a liquid human phantom. The total height of the designed antenna is 5 mm and the diameter is 10 mm. The fractional bandwidth of the fabricated antenna is about 21% with a voltage standing-wave ratio of less than 2, and it has an isotropic radiation pattern. These characteristics are suitable for wideband capsule endoscope systems. Moreover, the received power level was measured using the proposed antenna, a circular polarized receiver antenna, and a pig under general anesthesia. Finally, endoscopic capsule images in the stomach and large intestine were captured using an on-off keying transceiver system. PMID:21317074

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

2011-06-01

370

Design and Optimization of Wideband Multilayer Printed Antenna Arrays  

E-print Network

Design and Optimization of Wideband Multilayer Printed Antenna Arrays B. Riviere, Dr. H. Jeuland of ONERA recent research work in the field of wideband printed antenna arrays. A special focus will be given to the comprehensive analysis and design optimization of multilayered printed arrays for wide

371

Survey of worldwide high-power wideband capabilities  

Microsoft Academic Search

Wideband and ultrawideband (UWB) technologies have achieved notable progress in recent years, aided immeasurably by improvements in solid-state manufacturing, computers, and digitizers. As a result, wideband systems that were difficult or impossible to implement ten years ago are now being built for an increasingly wide variety of applications including transient radar, concealed object detection, mine clearing, pipeline inspections, archeology, geology,

William D. Prather; Carl E. Baum; Robert J. Torres; Frank Sabath; Daniel Nitsch

2004-01-01

372

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

373

Wideband high impedance surface for X-band antenna applications  

Microsoft Academic Search

A novel structure composed of frequency selective surface printed elements implemented on a grounded dielectric slab is proposed for the design of wideband artificial magnetic conductors. In this design, a printed cross with a slot at the center is combined with an L-shaped unclosed rectangular loop, which enables to obtain a wideband high impedance surface. The bandwidth of the surface

Gopinath Gampala; Alexander B. Yakovlev

2007-01-01

374

Computer Modeling of Wideband Quad-Ridge Horn  

E-print Network

Computer Modeling of Wideband Quad-Ridge Horn Microwave Antenna Feeds Gabe A. Cohn RF and Microwave. #12;Gabe Cohn 1 Table of Contents 1 Background on Lindgren Quad-Ridge Horn Feeds 4 1.1 ETS discusses the modeling and simulation of wideband quad-ridge microwave feeds made by ETS-Lindgren. Computer

Weinreb, Sander

375

A Miniature Wideband Internal Antenna with Dual Resonant Structures  

E-print Network

A Miniature Wideband Internal Antenna with Dual Resonant Structures Young Jun Cho, Yong Sun Shin a miniature wideband internal antenna with dual resonant structures for operating at multi-band handset. The electrical and structural characteristics of the proposed antenna make it attractive for use in mobile

Park, Seong-Ook

376

Capacity and mutual information of wideband multipath fading channels  

Microsoft Academic Search

We investigate the capacity and mutual information of a broadband fading channel consisting of a finite number of time-varying paths. We show that the capacity of the channel in the wideband limit is the same as that of a wideband Gaussian channel with the same average received power. However, the input signals needed to achieve the capacity must be “peaky”

Ì. Emre Telatar; David N. C. Tse

2000-01-01

377

SWARM: A Compact High Resolution Correlator and Wideband VLBI Phased Array Upgrade for SMA  

NASA Astrophysics Data System (ADS)

A new digital back end (DBE) is being commissioned on Mauna Kea. The “SMA Wideband Astronomical ROACH2 Machine”, or SWARM, processes a 4 GHz usable band in single polarization mode and is flexibly reconfigurable for 2 GHz full Stokes dual polarization. The hardware is based on the open source Reconfigurable Open Architecture Computing Hardware 2 (ROACH2) platform from the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). A 5 GSps quad-core analog-to-digital converter board uses a commercial chip from e2v installed on a CASPER-standard printed circuit board designed by Homin Jiang’s group at ASIAA. Two ADC channels are provided per ROACH2, each sampling a 2.3 GHz Nyquist band generated by a custom wideband block downconverter (BDC). The ROACH2 logic includes 16k-channel Polyphase Filterbank (F-engine) per input followed by a 10 GbE switch based corner-turn which feeds into correlator-accumulator logic (X-engines) co-located with the F-engines. This arrangement makes very effective use of a small amount of digital hardware (just 8 ROACH2s in 1U rack mount enclosures). The primary challenge now is to meet timing at full speed for a large and very complex FPGA bit code. Design of the VLBI phased sum and recorder interface logic is also in process. Our poster will describe the instrument design, with the focus on the particular challenges of ultra wideband signal processing. Early connected commissioning and science verification data will be presented.

Weintroub, Jonathan

2014-06-01

378

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

379

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

380

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.

381

Solving Autonomy Technology Gaps through Wireless Technology and Orion Avionics Architectural Principles  

NASA Astrophysics Data System (ADS)

Currently, autonomy in space applications is limited by a variety of technology gaps. Innovative application of wireless technology and avionics architectural principles drawn from the Orion crew exploration vehicle provide solutions for several of these gaps. The Vision for Space Exploration envisions extensive use of autonomous systems. Economic realities preclude continuing the level of operator support currently required of autonomous systems in space. In order to decrease the number of operators, more autonomy must be afforded to automated systems. However, certification authorities have been notoriously reluctant to certify autonomous software in the presence of humans or when costly missions may be jeopardized. The Orion avionics architecture, drawn from advanced commercial aircraft avionics, is based upon several architectural principles including partitioning in software. Robust software partitioning provides "brick wall" separation between software applications executing on a single processor, along with controlled data movement between applications. Taking advantage of these attributes, non-deterministic applications can be placed in one partition and a "Safety" application created in a separate partition. This "Safety" partition can track the position of astronauts or critical equipment and prevent any unsafe command from executing. Only the Safety partition need be certified to a human rated level. As a proof-of-concept demonstration, Honeywell has teamed with the Ultra WideBand (UWB) Working Group at NASA Johnson Space Center to provide tracking of humans, autonomous systems, and critical equipment. Using UWB the NASA team can determine positioning to within less than one inch resolution, allowing a Safety partition to halt operation of autonomous systems in the event that an unplanned collision is imminent. Another challenge facing autonomous systems is the coordination of multiple autonomous agents. Current approaches address the issue as one of networking and coordination of multiple independent units, each with its own mission. As a proof-of-concept Honeywell is developing and testing various algorithms that lead to a deterministic, fault tolerant, reliable wireless backplane. Just as advanced avionics systems control several subsystems, actuators, sensors, displays, etc.; a single "master" autonomous agent (or base station computer) could control multiple autonomous systems. The problem is simplified to controlling a flexible body consisting of several sensors and actuators, rather than one of coordinating multiple independent units. By filling technology gaps associated with space based autonomous system, wireless technology and Orion architectural principles provide the means for decreasing operational costs and simplifying problems associated with collaboration of multiple autonomous systems.

Black, Randy; Bai, Haowei; Michalicek, Andrew; Shelton, Blaine; Villela, Mark

2008-01-01

382

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

383

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

384

Wideband versatile radio-frequency spectrum analyzer  

NASA Astrophysics Data System (ADS)

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.

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

2003-03-01

385

Wide-band laser communications in space.  

NASA Technical Reports Server (NTRS)

Candidate wideband (1 Gbit/sec) satellite laser communications systems are compared with respect to projected component technology and launch cost. It appears that the carbon dioxide (10.6-micron) system offers a SNR advantage over the Nd:YAG (1.06-micron) or doubled Nd:YAG (0.53-micron) systems for comparable satellite burden. The launch costs for the carbon dioxide and doubled Nd:YAG systems can be similar, but the latter is very sensitive to the projected weight of a large lightweight photon-bucket receiving aperture. The most critical technology problem for the carbon dioxide system is that of Doppler compensation.

Forster, D. C.; Goodwin, F. E.; Bridges, W. B.

1972-01-01

386

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. 28 figs.

Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.

1996-09-17

387

System-level Analysis of an Ultra-Low Power, Low Data-rate FHSS Transceiver  

Microsoft Academic Search

The market of wireless connectivity is grow- ing rapidly. Various standards have been developed to sat- isfy the market. The area of ultra-low power, low data rate applications aims to become one of the most attractive ar- eas in terms of revenue. Possible flelds of application for ultra-low power low data rate networks can be the fol- lowing: domotica, automotive,

Emanuele Lopelli; Johan van der Tang; Arthur van Roermund

2004-01-01

388

Wideband Low-Profile Antenna Arrays: Fundamental Limits and Practical Implementations  

NASA Astrophysics Data System (ADS)

Advanced wireless communication and sensing systems have created a growing need for high performance, compact antennas. Low-profile wideband phased arrays are of particular interest, and have recently been shown to be capable of extremely large bandwidths. However, the size, weight, and cost of phased arrays still makes them impractical for many applications. The development of thinner, lightweight, and inexpensive wideband arrays is critical to improving the capabilities of small platforms such as small unmanned aerial vehicles. Like all antennas, phased arrays are limited by a fundamental compromise between size and performance. Although the theoretical limitations of electrically small antennas have been well known for over 60 years, similarly general limits have not yet been developed for periodic antenna arrays. In the first part of this thesis, we derive a new fundamental bandwidth limit for any periodic array that is backed by a conducting ground plane and constructed from passive and reciprocal materials. This limit is related to several critical design factors, including the array's thickness, polarization, scan angle, materials used, as well as the overall complexity of the array design. We also consider the common case when all radiating currents are confined to a thin planar sheet placed above the ground plane. We show here that such planar phased arrays have a fundamental impedance bandwidth limit of 8.3:1 (with VSWR ?2:1), in the absence of material loading. This bandwidth may be further improved by adding dielectric superstrate or magnetic substrate material layers. Knowledge of such fundamental bandwidth limits is extremely useful in the design of practical wideband arrays, which is the focus of the second part of this thesis. A key challenge with many wideband arrays is developing a feed circuit that supports extremely wide bandwidths without significantly adding to the size, weight, and cost of the design. Here, we demonstrate a novel approach that overcomes this problem by exploiting the natural reactance of the feed circuit as a simple impedance matching network for the array. The result is a simultaneous reduction in size and weight and improvement in bandwidth compared to other feeding techniques. We refer to our design as the Tightly Coupled Dipole Array with Integrated Balun (TCDA-IB), and it achieves 7.35:1 bandwidth while maintaining a low VSWR of ? 2.65:1 while scanning to +/- 45° in all planes. A prototype 8x8 array was constructed and demonstrated excellent performance relative to simulation. We also demonstrate that by adding reconfigurable components to the TCDA-IB, its maximum scan angle may by increased to as much as +/- 70° while maintaining a 5:1 impedance bandwidth. Our fundamental bandwidth limits reveal for the first time the extent of the realizable design space for wideband low-profile arrays, and suggest there are significant opportunities for further improvement. Several practical techniques are also presented for increasing bandwidth and scanning performance while reducing the total size, weight and cost of the array. In summary, the ongoing development of high-performance wideband low-profile arrays will likely remain an important and fertile area of research for the foreseeable future.

Doane, Jonathan

389

Wireless Downtowns  

NSDL National Science Digital Library

Coming soon to an urban center near you: wireless connectivity for your laptop or PDA, brought to you by City Hall. At least that's the hot trend among U.S. municipalities, 48 of which now offer wireless access, according to a recent report. Most municipal systems are the result of public-private partnerships, and many offer some level of free access. The first website (1) is an overview of the wireless downtown phenomenon which notes the importance of such systems for local economic development. The second link (2) is to a fact sheet about Wireless Philadelphia, which, as one of the first and largest downtown wi-fi projects, helped spark the national trend. The third website is a node map of NYCwireless (3) and the 147 access points where that municipal network currently can be accessed. The fourth link leads to a case study of chaska.net (4) , which provides wireless access to the 7,500 homes and 18,000 residents of that Minneapolis suburb. The fifth website is a pdf (5) of a slick brochure produced by the city of Gainesville, Fla., to promote its Digital Downtown project. The sixth link is to a Sacramento Bee editorial (6) making the case for downtown wireless. The seventh website is a free database listing 10,840 wireless access points in 767 locations worldwide (7) , organized by geographic region.

390

High temperature superconductive wideband compressive receivers  

SciTech Connect

Wideband compressive receivers are an attractive application niche for analog high temperature superconductive (HTS) microwave filters. Chirp filters form the basis of compressive receivers, implementing a chirp-transform algorithm in the analog domain for real-time spectral analysis. HTS tapped-delay-line chirp filters are an enabling technology for instantaneous bandwidths greater than 1 GHz, and have evolved sufficiently to support dispersive delays as long as 40 ns with multigigahertz bandwidths and time-bandwidth products in excess of 100. Long dispersive delays have been obtained using a bonded/thinned-wafer technique to fabricate YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} stripline devices on 5-mil-thick, 2-in-diameter LaAlO{sub 3} substrates. These filters have produced better than {minus}18-dB error sidelobes. In addition, a 3-GHz-bandwidth HTS compressive cueing receiver was recently delivered to the Naval Research Laboratory to be flown on the high temperature superconductor space experiment (HTSSE), and demonstrations have been performed combining HTS chirp filters with conventional compressive-receiver hardware. A novel compressive cryoreceiver architecture is proposed combining HTS, cryoelectronic, and advanced high-speed semiconductor technologies. The proposed receiver will rival the sensitivity of a narrowband receiver while providing unprecedented wideband instantaneous frequency coverage. Future developments will extend the bandwidth capability. Applications include electronic warfare and dynamic molecular spectroscopy for remote sensing.

Lyons, W.G.; Arsenault, D.R.; Anderson, A.C.; Sollner, T.C.L.G.; Murphy, P.G.; Seaver, M.M.; Boisvert, R.R.; Slattery, R.L.; Ralston, R.W. [Massachusetts Inst. of Tech., Lexington, MA (United States)] [Massachusetts Inst. of Tech., Lexington, MA (United States)

1996-07-01

391

Dynamic range considerations in narrowband and wideband superheterodyne surveillance receivers  

NASA Astrophysics Data System (ADS)

This report examines the dynamic range performance of narrowband and wideband superheterodyne surveillance receivers. A theoretical review of parameters indicative of the dynamic range performance of each type of receiver is presented. It is seen that for a narrowband superheterodyne receiver, the dynamic range performance can be specified using a parameter based on a single tone at the input. For a wideband superheterodyne receiver, one or more two tone dynamic range parameters are needed. These two tone dynamic range parameters are then used to predict the dynamic range performance of a wideband superheterodyne surveillance receiver currently being built for DREO. Some anticipated dynamic range problems specific to this system are discussed.

Mudry, Andrew

1988-03-01

392

1370 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 57, NO. 5, MAY 2009 Paper-Based RFID-Enabled Wireless  

E-print Network

-Based RFID-Enabled Wireless Platforms for Sensing Applications Rushi Vyas, Student Member, IEEE, Vasileios- tion (RFID), sensor, temperature, transmitter, ultra high frequency (UHF), wireless. I. INTRODUCTION AS THE demand for low cost, flexible, and power-efficient broadband wireless electronics increases

Tentzeris, Manos

393

Wireless Andrew.  

ERIC Educational Resources Information Center

Describes the use of the Internet and laptops help Carnegie Mellon University students carry out sophisticated research anywhere on campus. How the university became a wireless community is discussed. (GR)

Fickes, Michael

2000-01-01

394

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 Jozef

395

Prospector: Multiscale Energy Measurement of Networked Embedded Systems with Wideband  

E-print Network

-centric embedded systems. This paper describes Prospector, an energy data acquisition system architecture. Prospector uses a distributed control architecture; each component contributes efficiently to controlProspector: Multiscale Energy Measurement of Networked Embedded Systems with Wideband Power Signals

396

Wideband beamforming for a sparse nonuniformly spaced array  

NASA Astrophysics Data System (ADS)

This project concerns the continued development and evaluation of a computationally-efficient wideband adaptive beamformer for a large nonuniformly-spaced sensor array which effectively extends its operation to wavelengths which are considerably smaller than the average interelement spacing.

Krolik, Jeff

1994-01-01

397

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

398

High-latitude upgrade to the Wideband ionospheric scintillation model  

Microsoft Academic Search

The high-latitude sections of the Wideband ionospheric scintillation model (WBMOD) have been upgraded extensively, based on analysis of scintillation data from the De- fense Nuclear Agency Wideband, HiLat, and Polar BEAR satellite-beacon experiments. Data collected at Sondre Stromfjord, Greenland; Tromso, Norway; Fort Churchill, Canada; and Belle- vue, Washington (United States) over a 4-year period were analyzed, and the results of

J. A. Secan; R. M. Bussey; E. J. Fremouw; S. Basu

1997-01-01

399

High-latitude upgrade to the Wideband ionospheric scintillation model  

Microsoft Academic Search

The high-latitude sections of the Wideband ionospheric scintillation model (WBMOD) have been upgraded extensively, based on analysis of scintillation data from the Defense Nuclear Agency Wideband, HiLat, and Polar BEAR satellite-beacon experiments. Data collected at Sondre Stromfjord, Greenland; Tromso, Norway; Fort Churchill, Canada; and Bellevue, Washington (United States) over a 4-year period were analyzed, and the results of these analyses

J. A. Secan; R. M. Bussey; E. J. Fremouw; S. Basu

1997-01-01

400

Wideband scalable probe for Spherical Near-Field Antenna measurements  

Microsoft Academic Search

The paper presents a design of an open-boundary quad-ridged horn to be used as a wideband scalable dual-linearly polarized probe for spherical near-field antenna measurements. With a new higher-order probe correction technique developed at the Technical University of Denmark, the probe will enable high-accuracy wideband antenna measurements at the DTU-ESA Spherical Near-Field Antenna Test Facility at frequencies down to 400

Oleksiy S. Kim; Sergey Pivnenko; Olav Breinbjerg

2011-01-01

401

Co-design implementation of wireless bio-implant for real-time control and monitoring  

Microsoft Academic Search

Wireless biomedical implants are motivating great interest in modern medicine. Research challenges are presented due to the need for having a biocompatible, fault-tolerant, energy-efficient, and scalable design. Figuring out how to arrange and implant these wireless chips in human body adds additional research challenges. Wireless biomedical implants should be ultra-save in power consumption and reliable and have nominal maintenance. To

Lazhar Khriji; Nabil Hamza; Farid Touati

2008-01-01

402

A wireless body area network of intelligent motion sensors for computer assisted physical rehabilitation  

Microsoft Academic Search

BACKGROUND: Recent technological advances in integrated circuits, wireless communications, and physiological sensing allow miniature, lightweight, ultra-low power, intelligent monitoring devices. A number of these devices can be integrated into a Wireless Body Area Network (WBAN), a new enabling technology for health monitoring. METHODS: Using off-the-shelf wireless sensors we designed a prototype WBAN which features a standard ZigBee compliant radio and

Emil Jovanov; Aleksandar Milenkovic; Chris Otto; Piet C de Groen

2005-01-01

403

Design of Balanced RF Filter for Wireless Applications Using FBAR Technology  

Microsoft Academic Search

We present a balanced RF filter based on thin film bulk acoustic resonator (FBAR) technology for wireless applications, and demonstrate its usage in the wide-band code division multiple access (WCDMA) front-end as post-LNA filter. The filter, which consists of two lattice sections and one symmetric ladder section, provides deep rejection at stop-band, particularly at transmitter band (1920-1980 MHz), steep roll-off

Hao Jin; Shurong Dong; Demiao Wang

2005-01-01

404

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.

405

Design of a Wideband Radio Telescope  

NASA Technical Reports Server (NTRS)

A wideband Radio Telescope is being designed for use in the Goldstone Apple Valley Radio Telescope program. It uses an existing 34-meter antenna retrofitted with a tertiary offset mirror placed at the apex of the main reflector. It can be rotated to use two feeds that cover the 1.2 to 14 GHz band. The feed for 4.0 to 14.0 GHz is a cryogenically cooled commercially available open boundary quadridge horn from ETS-Lindgren. Coverage from 1.2 to 4.0 GHz is provided by an un-cooled scaled version of the same feed. The performance is greater than 40% over most of the band and greater than 55%from 6 to 13.5 GHz.

Imbriale, William A.; Weinreb, Sander; Mani, Handi

2007-01-01

406

Wideband DMOS amplifier competes with bipolars  

NASA Astrophysics Data System (ADS)

A wideband (40-350 MHz) hybrid DMOS or double-diffused metal oxide semiconductor amplifier is described that has been designed and built to demonstrate the feasibility of the device in cable communications systems (currently dominated by bipolar hybrid IC). The advantages of the DMOS transistor include high input impedance, high current gain and power gain, and no thermal runaway problems. Furthermore, in a DMOS, a very short channel length (a micron or less) is possible without submicrometer lithography, and a high breakdown voltage can be obtained and tailored independently of the channel length by incorporating a lightly doped drift region between the active region and the drain contact. Three circuit configurations were investigated: multiple feedback, cascode, and cascade. Thick-film technology was used to implement the circuit. Amplifier characteristics are tabulated.

Salama, C. A. T.; Sin, J. K. O.

1986-06-01

407

Wideband RF Structure for Millimeter Wave TWTs  

NASA Astrophysics Data System (ADS)

LANL has developed a new vane loaded waveguide RF structure for a sheet electron beam traveling wave tube (TWT). The goal was to create a new class of wideband RF structures that allow simple mechanical fabrication and have geometry suitable for interaction with sheet electron beams. We have concentrated on structures at 94 GHz. We have achieved 6% bandwidth and believe that 10% is possible. We have performed 3D electromagnetic simulations using the codes Microwave Studio and HFSS, and fabricated several aluminium cold models of RF structures at 10GHz to confirm the design. Agreement between the 10 GHz cold test data and computer simulations was excellent. An RF structure at 94GHz was fabricated using electrical discharge machining (EDM) with a 0.004 inch wire and cold tested.

Earley, Lawrence; Carlsten, Bruce; Krawczyk, Frank; Potter, James; Sigler, Floyd; Smirnova, Evgenia; Wheat, Robert; Heath, Cynthia; Bailey, Aimee

2006-01-01

408

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

409

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

410

Application of the Method of Auxiliary Sources to the Wideband Electromagnetic Induction Problem  

E-print Network

Application of the Method of Auxiliary Sources to the Wideband Electromagnetic Induction Problem F of auxiliary sources (MAS) is formulated and applied to solution of wideband electromagnetic induction problems. INTRODUCTION The investigation of electromagnetic induction (EMI) problems involving highly conducting

Shubitidze, Fridon

411

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

412

Software defined radio layer for IR-UWB systems in Wireless Sensor Network Context  

E-print Network

This paper addresses the radio interface problematic for MANET (Mobile Ad-hoc NETwork) applications. Here we propose to study the radio reconfigurability in order to provide a unique physical layer which is able to deal with all MANET applications. For implementing this reconfigurable physical layer, we propose to use Impulse Radio Ultra WideBand (IRUWB). This paper presents also our two level design approach for obtaining our reconfigurable IR-UWB receiver on FPGA (Field Programmable Gate Array).

Lecointre, Aubin; Plana, Robert

2010-01-01

413

Comparative analysis of the narrowband and wideband methods of target recognition  

Microsoft Academic Search

Results of comparative study of radar recognition with the use of narrowband and wideband signals as well as various recognition signatures are presented. The advantage of wideband radar signals is emphasized. The results show that use of wideband signals allow increasing the accuracy of radar measurements and radar immunity against interference providing the same detection range.

S. P. Leshchenko

2004-01-01

414

Analysis and Design of Compact Wideband Baluns on Multilayer Liquid Crystalline Polymer (LCP) Based Substrates  

E-print Network

Analysis and Design of Compact Wideband Baluns on Multilayer Liquid Crystalline Polymer (LCP) Based LCP packaging technology, a wideband balun operating in the 5GHz band has been designed and fabricated circuits, wideband, embedded passives, LCP, organic substrates, SOP, system-on-package. I. INTRODUCTION

Swaminathan, Madhavan

415

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 to design a traditional wideband LPDA antenna to operate in the range from 1 GHz to 10 GHz. WIPL-D allows

Elsherbeni, Atef Z.

416

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.

417

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

418

Wireless Protection.  

ERIC Educational Resources Information Center

Discusses wireless access-control equipment in the school and university setting, particularly the integrated reader lock at the door with a panel interface module at the control panel. Describes its benefits, how it works, and its reliability and security. (EV)

Conforti, Fred

2003-01-01

419

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

420

Tremor acquisition system based on UWB Wireless Sensor Network  

E-print Network

Tremor acquisition system based on UWB Wireless Sensor Network G. Blumrosen1 , M. Uziel2 , B.porrat@huji.ac.il, rubinsky@cs.huji.ac.il Abstract--This work suggest to quantify and analyze tremor using Ultra Wide contact tremor assessment with extremely low radiation and penetration through walls. Tremor is the target

Porrat, Dana

421

Wireless communication using detectors located inside vacuum chambers  

Microsoft Academic Search

Progress in modern vacuum technology requires an increasing number of measurements to be performed in the vacuum environment itself and in many applications data transfer outside the vacuum vessels is both difficult and expensive. This paper explores the potential of wireless technology to transmit data from and into ultra high vacuum (UHV) compatible vacuum chambers using glass viewport windows attached

A. Murari; L. Lotto

2003-01-01

422

A Wideband Spectrometer with RFI Detection  

NASA Astrophysics Data System (ADS)

We report on the design and construction of a wideband spectrometer of 500 MHz instantaneous bandwidth that includes automatic radio frequency interference (RFI) detection. The implementation is based on hardware developed at the Center for Astronomical Signal Processing and Electronics Research (CASPER). The unique aspect of the spectrometer is that it accumulates both power and power-squared, which are then used to develop a spectral kurtosis (SK) estimator. The SK estimator statistics are used for real-time detection and excision of certain types of RFI embedded in the received signal. We report on the use of this spectrometer in the Korean Solar Radio Burst Locator (KSRBL). This instrument utilizes four of these 500 MHz bandwidth SK spectrometers in parallel, to achieve a 2 GHz instantaneous bandwidth that is time multiplexed over the entire 0.24-18 GHz radio frequency range, to study solar bursts. The performance of the spectrometers for excising RFI over this range is presented. It is found that the algorithm is especially useful for excising highly intermittent RFI but is less successful for RFI due to digital signals. A method we call multiscale SK is presented that addresses the known blindness of Kurtosis-based estimators to 50% duty-cycle RFI. The SK algorithm can also be applied to spectral channels prior to correlation to remove unwanted RFI from interferometer data.

Gary, Dale E.; Liu, Zhiwei; Nita, Gelu M.

2010-05-01

423

Wideband Frequency Synthesizer at X/Ku Band by Mixing and Phase Locking of Half Frequency Output of VCO  

NASA Astrophysics Data System (ADS)

A wideband low phase noise frequency synthesizer at X/Ku band has been developed by using phase locking and mixing technique at half frequency of voltage controlled oscillator (VCO). The half frequency output signal of the VCO is down converted by a balanced mixer at C band to obtain an intermediate frequency (IF) signal used for phase locking of the VCO. An ultra low phase noise local signal source at 6 GHz is developed with a frequency multiplying chain driven by a 100 MHz oven controlled crystal oscillator (OCXO). Coupling circuit outside the VCO chip to the mixer does not need to be specially designed, which is beneficial to simplify the circuit scheme and improve the phase noise performance. Measurement results show that the phase noise of the output signal at 10.6 GHz to 11.8 GHz and 12.3 GHz to 13.0 GHz is better than -102 dBc/Hz at 10 kHz away form the carrier center. This frequency synthesizer can be used as local signal source or driving source for the development of wideband millimeter-wave frequency synthesizer systems.

Chen, Mo; Xu, Jinping

2010-01-01

424

EMC and wireless healthcare  

Microsoft Academic Search

Electromagnetic compatibility (EMC) is a critical part of addressing the risks related to the effects of electromagnetic interference (EMI) on active medical devices exposed to emissions from wireless technology. In addition, for wireless technology in healthcare to be safe, effective, reliable, and secure specific wireless issues must also be addressed including quality of service, coexistence with other wireless equipment, data

Donald Witters; Seth Seidman; Howard Bassen

2010-01-01

425

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

426

Wideband Gap Coupled Assembly of Rectangular Microstrip Patches for Wi-Max Applications  

NASA Astrophysics Data System (ADS)

This paper presents a wideband gap coupled assembly of rectangular microstrip patches applicable in lower and upper band of Wi-Max applications utilizing six directly and parasitically coupled patches. Considered assembly of patches on glass epoxy FR4 substrate has overall dimension of 40.0 mm by 52.88 mm. The proposed antenna is designed to function in the lower band (2.4-2.69 GHz) and upper band (5.25-5.85 GHz) of Wi-Max systems. The antenna is simulated using IE3D simulation software in view of the Wi-Max standards adopted by IEEE 802.16 working group. The simulated and measured results are well in agreement and show that antenna resonates in two bands proposed for wireless communication applications and successfully achieves the bandwidth of 11.2% (at VSWR: 1.5) with respect to the center frequency of 2.84 GHz in lower band and 9.7% with respect to the center frequency of 5.39 GHz in upper band. Gain and efficiency of antenna in these two bands are however low due to lossy substrate but radiation patterns in each of these two bands are identical in shape in entire bandwidth region. In lower band maximum radiations may be achieved normal to patch geometry but in upper band, direction of maximum radiations is inclined at ? = 60° perhaps due to the generation of higher mode.

Sharma, Vijay; Sharma, M. M.

2014-01-01

427

An Inverter-Based Wideband Low-Noise Amplifier in 40 nm Complementary Metal Oxide Semiconductor  

NASA Astrophysics Data System (ADS)

Multistandard RF chips have been highly demanded for multipurpose wireless applications. However, in RF circuits, a low-noise amplifier (LNA) plays an important role in determining the receiver's performance. In this paper, we present a scalable wideband LNA based on complementary metal oxide semiconductor (CMOS) inverters, employing two bandwidth expansion techniques to achieve a large bandwidth without using inductors. Fabricated by the 40 nm CMOS process, the LNA attains 0.1-8.0 GHz of flat bandwidth with S21=17.5 dB and S11?-10 dB. The minimum NF measured is 5.1 dB and the power consumption is 14.3 mW at 1.3 V. The LNA core circuit is as small as 0.001 mm2 since no large passive device is used. A study of LNA scalability has been conducted by comparing the performances of circuits with the same topology fabricated by the 65, 90, and 180 nm CMOS processes.

Nur Salmi Dharmiza, Dayang; Oturu, Mototada; Tanoi, Satoru; Ito, Hiroyuki; Ishihara, Noboru; Masu, Kazuya

2012-04-01

428

An Inverter-Based Wideband Low-Noise Amplifier in 40 nm Complementary Metal Oxide Semiconductor  

NASA Astrophysics Data System (ADS)

Multistandard RF chips have been highly demanded for multipurpose wireless applications. However, in RF circuits, a low-noise amplifier (LNA) plays an important role in determining the receiver's performance. In this paper, we present a scalable wideband LNA based on complementary metal oxide semiconductor (CMOS) inverters, employing two bandwidth expansion techniques to achieve a large bandwidth without using inductors. Fabricated by the 40 nm CMOS process, the LNA attains 0.1--8.0 GHz of flat bandwidth with S21=17.5 dB and S11? -10 dB. The minimum NF measured is 5.1 dB and the power consumption is 14.3 mW at 1.3 V. The LNA core circuit is as small as 0.001 mm2 since no large passive device is used. A study of LNA scalability has been conducted by comparing the performances of circuits with the same topology fabricated by the 65, 90, and 180 nm CMOS processes.

Dharmiza, Dayang Nur Salmi; Oturu, Mototada; Tanoi, Satoru; Ito, Hiroyuki; Ishihara, Noboru; Masu, Kazuya

2012-04-01

429

Wideband Gapfiller Satellite system support for the Global Hawk mission  

Microsoft Academic Search

The main purpose of this paper is to document the findings of a study tasked by the joint staff regarding the potential supportability of the Global Hawk (GH) high data rate requirements using the Wideband Gapfiller Satellite (WGS). The joint staff tasking was based upon an intelligence program decision memorandum (IPDM) tasking investigating options for the support of the Global

R. A. Williams; H. I. Paul

2002-01-01

430

Spectral estimation of migrating targets in wideband radar  

Microsoft Academic Search

Low pulse repetition frequency radars aimed at detecting moving targets are faced with the problem of blind velocities, since Doppler ambiguous targets have to compete with clutter and possibly the sidelobes of strong targets. On the other hand, wideband radars offer high range resolution, and hence fast moving targets, in contrast to clutter or non moving targets, are likely to

F. Deudon; S. Bidon; O. Besson; J.-Y. Tourneret

2011-01-01

431

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

432

Timing Acquisition of Wideband PPM Systems over Multipath  

E-print Network

Timing Acquisition of Wideband PPM Systems over Multipath Dana Porrat School of Engineering for proper operation of PPM systems, and timing errors seriously degrade PPM system performance [1], [2]. Our- formed by a correlation operation followed by a threshold decision [5], [6], [7]. However, we have shown

Porrat, Dana

433

Compact wideband downconverter module for Electronic Warfare applications  

Microsoft Academic Search

Analysis and design of a compact wideband downconverter module for EW applications are presented in this paper. Architectural and circuit solutions trade-offs are described and related to the module's electrical and mechanical requirements and the key components characteristics. RF chain simulations and their comparison with measurements of the manufactured module are finally illustrated.

C. Pandolfi; M. Bartocci; G. Gabrielli; P. E. Longhi; A. Megna; B. Orobello

2009-01-01

434

Wideband beamforming for a sparse nonuniform spaced sensor array  

NASA Astrophysics Data System (ADS)

This project concerns the continued development and evaluation of a computationally-efficient wideband adaptive beamformer for a large non-uniformly-spaced sensor array which effectively extends its operation to wavelengths which are considerably smaller than the average inter-element spacing.

Krolik, Jeffrey

1993-04-01

435

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

436

WIDEBAND BOW-TIE SLOT ANTENNA WITH TUNING STUBS  

E-print Network

stub to a bow-tie slot antenna design to enhance the antenna bandwidth for X-band operation. Our study the commercial computer software package, Momentum of Agilent Technologies, Advanced Design System (ADS antenna that has wideband characteristics. A number of bow-tie slot designs are introduced in [8

Elsherbeni, Atef Z.

437

WIDEBAND 2D ARRAY OF MICROSTRIP FED RECTANGULAR-  

E-print Network

of antennas [2­12]. One purpose of the design of wideband antenna elements is to arrange them into an array array of a microstrip-proximity- fed rectangular-slot antenna is designed to support the new wide- band-antenna ele- ments and feed network are performed using the Momentum software package Advanced Design System

Elsherbeni, Atef Z.

438

Evolutionary Design of Wide-Band Parasitic Dipole Arrays  

Microsoft Academic Search

An innovative antenna design technique, based on evolutionary programming, has been devised and applied to the design of broadband parasitic wire arrays for VHF-UHF bands with a significant gain. The chosen fitness function includes far-field requirements, as well as wideband input matching speci- fications. The latter requirements, which must be present in every useful antenna design, allow to stabilize the

Giovanni Andrea Casula; Giuseppe Mazzarella; Nicola Sirena

2011-01-01

439

Real-Time Wideband Telemetry Receiver Architecture and Performance  

NASA Astrophysics Data System (ADS)

We describe the architecture and algorithm development for a field programmable gate array (FPGA) wideband telemetry receiver prototype capable of processing data rates in excess of 100 megabits per second (Mbps). The high-speed parallel implementations of the matched filter, carrier phase tracking loop, and symbol timing recovery loop are discussed, along with simulation and hardware performance results.

Andrews, K.; Gin, J.; Lay, N.; Quirk, K.; Srinivasan, M.

2006-08-01

440

Asymptotically perfect wideband focusing of multiring circular arrays  

Microsoft Academic Search

The concept of coherent focusing of sensor arrays, introduced by Wang and Kaveh, led to the development of high-performance and computationally efficient algorithms for wideband direction finding and beamforming. Nonetheless, the quality of focusing depends on the understanding and the proper exploitation of specific array manifold properties. Circular arrays exhibit uniform (isotropic) performance over the entire azimuthal range and allow

Elio D. Di Claudio

2005-01-01

441

An electromagnetic micro power generator for wideband environmental vibrations  

Microsoft Academic Search

This paper presents a wideband electromagnetic vibration-to-electrical micro power generator. The micro generator is capable of generating steady power over a predetermined frequency range. Power is generated by means of the relative motion between a magnet and coils fabricated over resonating cantilevers through electromagnetic induction. The reported generator covers a wide band of external vibration frequency by implementing a number

Ibrahim Sari; Tuna Balkan; Haluk Kulah

2008-01-01

442

Wideband nulling capability estimate of a tapped delay line beamformer  

Microsoft Academic Search

We have attempted to quantify the maximum number of wideband interference signals that can be sufficiently nulled under severe interference scenarios, using a tapped delay line beamformer with a fixed number of antenna elements (M). Evaluation of simulation results shows that for increasing the fractional bandwidth, more taps are needed, but to a certain limit. In addition, the results show

L. Y. Materum

2003-01-01

443

Wide-band array signal processing via spectral smoothing  

NASA Astrophysics Data System (ADS)

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

1989-11-01

444

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

E-print Network

and for IF amps in THz receivers 3. Recent SiGe LNA developments 4. 1 to 20 and 8 to 50 GHz LNA designs 5. Quad-ridge flared horn wideband feeds #12;Wafer Fabrication of LNA's and Other Radiometer Components 20-Sep-2011

Weinreb, Sander

445

A note on the wide-band Gaussian broadcast channel  

NASA Technical Reports Server (NTRS)

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

1987-01-01

446

Simple phenomenological models for wideband frequency-domain electromagnetic induction  

Microsoft Academic Search

The authors propose three phenomenological models for wideband electromagnetic induction (EMI) response of buried conductors, such as unexploded ordnance (UXO) or metal parts in landmines. The models are based on analytic solutions for spheres, cylinders, and wire loops, and produce physically reasonable predictions for a variety of targets at all frequencies of interest including matches to theory in the low-

Jonathan T. Miller; Thomas H. Bell; Judy Soukup; Dean Keiswetter

2001-01-01

447

Frequency and bandwidth agile pulser for use in wideband applications  

Microsoft Academic Search

We have developed an architecture to produce a wideband pulser that is tunable in the important parameters of pulsewidth, bandwidth, and center frequency. The pulser is based on a parallel plate Blumlein pulse-forming network (PFN) with a movable center (charge) conductor. When the center conductor is displaced from the ideal Blumlein position, the balance in the PFN is lost, resulting

J. Scott Tyo; Michael C. Skipper; Michael D. Abdalla; Samuel P. Romero; Brett Cockreham

2004-01-01

448

Determination of Propagation Mechanisms Using Wideband Measurement Techniques - Abstract  

Microsoft Academic Search

In this paper we propose using wideband measurement techniques to determine propagation mechanisms. The factors that can affect the accuracy of the measurements are analyzed. The delay profiles can be obtained by applying inverse fast Fourier transforming (IFFT) on the measured frequency response. To avoid range ambiguity in the delay profile, the frequency response should be finely sampled. The peak

H. J. Li; H. C. Lin; C. C. Chen; T. Y. Liu

1998-01-01

449

Wide-band gas leak imaging detection system using UFPA  

NASA Astrophysics Data System (ADS)

The leakage of toxic or hazardous gases not only pollutes the environment, but also threatens people's lives and property safety. Many countries attach great importance to the rapid and effective gas leak detection technology and instrument development. However, the gas leak imaging detection systems currently existing are generally limited to a narrow-band in Medium Wavelength Infrared (MWIR) or Long Wavelength Infrared (LWIR) cooled focal plane imaging, which is difficult to detect the common kinds of the leaking gases. Besides the costly cooled focal plane array is utilized, the application promotion is severely limited. To address this issue, a wide-band gas leak IR imaging detection system using Uncooled Focal Plane Array (UFPA) detector is proposed, which is composed of wide-band IR optical lens, sub-band filters and switching device, wide-band UFPA detector, video processing and system control circuit. A wide-band (3µm~12µm) UFPA detector is obtained by replacing the protection window and optimizing the structural parameters of the detector. A large relative aperture (F#=0.75) wide-band (3?m~12?m) multispectral IR lens is developed by using the focus compensation method, which combining the thickness of the narrow-band filters. The gas leak IR image quality and the detection sensitivity are improved by using the IR image Non-Uniformity Correction (NUC) technology and Digital Detail Enhancement (DDE) technology. The wide-band gas leak IR imaging detection system using UFPA detector takes full advantage of the wide-band (MWIR&LWIR) response characteristic of the UFPA detector and the digital image processing technology to provide the resulting gas leak video easy to be observed for the human eyes. Many kinds of gases, which are not visible to the naked eyes, can be sensitively detected and visualized. The designed system has many commendable advantages, such as scanning a wide range simultaneously, locating the leaking source quickly, visualizing the gas plume intuitively and so on. The simulation experiment shows that the gas IR imaging detection has great advantages and widely promotion space compared with the traditional techniques, such as point-contact or line-contactless detection.

Jin, Wei-qi; Li, Jia-kun; Dun, Xiong; Jin, Minglei; Wang, Xia

2014-11-01

450

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

451

An ultra-low-power RF transceiver for WBANs in medical applications  

Microsoft Academic Search

A 2.4 GHz ultra-low-power RF transceiver with a 900 MHz auxiliary wake-up link for wireless body area networks (WBANs) in medical applications is presented. The RF transceiver with an asymmetric architecture is proposed to achieve high energy efficiency according to the asymmetric communication in WBANs. The transceiver consists of a main receiver (RX) with an ultra-low-power free-running ring oscillator and

Zhang Qi; Kuang Xiaofei; Wu Nanjian

2011-01-01

452

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

453

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 Recent Results: CAD Software for Modeling Arbitrary UWB Antennas and Links How can antennas and realistic: Practical Antenna Designs for UWB Systems What is the best antenna for UWB radio systems ? The choice

Southern California, University of

454

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

455

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

456

Wide-Band Source Localization in the Alpha-Stable In this chapter, we study the problem of localizing wide-band sources in the presence of  

E-print Network

Chapter 6 Wide-Band Source Localization in the Alpha-Stable Framework In this chapter, we study the problem of localizing wide-band sources in the presence of noise modeled as a complex isotropic stable to the localization problem of narrow-band sources in the presence of noise modeled as a complex isotropic Cauchy

Tsakalides, Panagiotis

457

Ultra-high throughput real-time instruments for capturing fast signals and rare events  

NASA Astrophysics Data System (ADS)

Wide-band signals play important roles in the most exciting areas of science, engineering, and medicine. To keep up with the demands of exploding internet traffic, modern data centers and communication networks are employing increasingly faster data rates. Wide-band techniques such as pulsed radar jamming and spread spectrum frequency hopping are used on the battlefield to wrestle control of the electromagnetic spectrum. Neurons communicate with each other using transient action potentials that last for only milliseconds at a time. And in the search for rare cells, biologists flow large populations of cells single file down microfluidic channels, interrogating them one-by-one, tens of thousands of times per second. Studying and enabling such high-speed phenomena pose enormous technical challenges. For one, parasitic capacitance inherent in analog electrical components limits their response time. Additionally, converting these fast analog signals to the digital domain requires enormous sampling speeds, which can lead to significant jitter and distortion. State-of-the-art imaging technologies, essential for studying biological dynamics and cells in flow, are limited in speed and sensitivity by finite charge transfer and read rates, and by the small numbers of photo-electrons accumulated in short integration times. And finally, ultra-high throughput real-time digital processing is required at the backend to analyze the streaming data. In this thesis, I discuss my work in developing real-time instruments, employing ultrafast optical techniques, which overcome some of these obstacles. In particular, I use broadband dispersive optics to slow down fast signals to speeds accessible to high-bit depth digitizers and signal processors. I also apply telecommunication multiplexing techniques to boost the speeds of confocal fluorescence microscopy. The photonic time stretcher (TiSER) uses dispersive Fourier transformation to slow down analog signals before digitization and processing. The act of time-stretching effectively boosts the performance of the back-end electronics and digital signal processors. The slowed down signals reach the back-end electronics with reduced bandwidth, and are therefore less affected by high-frequency roll-off and distortion. Time-stretching also increases the effective sampling rate of analog-to-digital converters and reduces aperture jitter, thereby improving resolution. Finally, the instantaneous throughputs of digital signal processors are enhanced by the stretch factor to otherwise unattainable speeds. Leveraging these unique capabilities, TiSER becomes the ideal tool for capturing high-speed signals and characterizing rare phenomena. For this thesis, I have developed techniques to improve the spectral efficiency, bandwidth, and resolution of TiSER using polarization multiplexing, all-optical modulation, and coherent dispersive Fourier transformation. To reduce the latency and improve the data handling capacity, I have also designed and implemented a real-time digital signal processing electronic backend, achieving 1.5 tera-bit per second instantaneous processing throughput. Finally, I will present results from experiments highlighting TiSER's impact in real-world applications. Confocal fluorescence microscopy is the most widely used method for unveiling the molecular composition of biological specimens. However, the weak optical emission of fluorescent probes and the tradeoff between imaging speed and sensitivity is problematic for acquiring blur-free images of fast phenomena and cells flowing at high speed. Here I introduce a new fluorescence imaging modality, which leverages techniques from wireless communication to reach record pixel and frame rates. Termed Fluorescence Imaging using Radio-frequency tagged Emission (FIRE), this new imaging modality is capable of resolving never before seen dynamics in living cells - such as action potentials in neurons and metabolic waves in astrocytes - as well as performing high-content image assays of cells and particles in high-speed flow.

Buckley, Brandon Walter

458

A wide-band slot antenna design employing a fictitious short circuit concept  

Microsoft Academic Search

A wide-band slot antenna element is proposed as a building block for designing single- or multi-element wide-band or dual-band slot antennas. It is shown that a properly designed, off-centered, microstrip-fed, moderately wide slot antenna shows dual resonant behavior with similar radiation characteristics at both resonant frequencies and therefore can be used as a wide-band or dual-band element. This element shows

Nader Behdad; Kamal Sarabandi

2005-01-01

459

High quality coding of wideband speech at 24 kbit\\/s  

Microsoft Academic Search

This paper proposes a Wideband-CELP-Coding scheme (bandwidth 7kHz) at 24 kbit\\/s. The codec introduces a de- lay of just 10 ms. This fulfills the requirements of a possible codec candidate for wideband speech coding within DECT or video applications (I). The analysis-by-synthesis struc- ture of the proposed Wideband-CELP-Codec includes an alternative LPC analysis concept, where the autocorrela- tion function is

Jurgen Paulus; Christiane Antweiler; Christian G. Gerlach

1993-01-01

460

All-fiber, ultra-wideband tunable laser at 2 ?m.  

PubMed

We report a direct diode-pumped all-fiber tunable laser source at 2 ?m with a tuning range of more than 250 nm. A 3 dB power flatness of 200 nm with a maximum output power of 30 mW at 1930 nm was achieved. The laser has a high optical signal-to-noise ratio (OSNR) of more than 40 dB across the whole tuning range. PMID:24322120

Li, Z; Alam, S U; Jung, Y; Heidt, A M; Richardson, D J

2013-11-15

461

Experimental evaluation of a SAGE algorithm for ultra wideband channel sounding in an anechoic chamber  

Microsoft Academic Search

The paper presents the results of experiments in an anechoic chamber that assessed the reliability of a UWB channel sounding system based on a deterministic approach with a SAGE algorithm. The system could resolve and detect waves separated by 10° in the angle domain, which was near the resolution limit. In the delay domain, waves separated by 0.67 ns could

K. Haneda; J. I. Takada; T. Kobayashi

2004-01-01

462

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

463

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

464

Graphene as a high impedance surface for ultra-wideband electromagnetic waves  

SciTech Connect

The metals are regularly used as reflectors of electromagnetic fields emitted by antennas ranging from microwaves up to THz. To enhance the reflection and thus the gain of the antenna, metallic high impedance surfaces (HIS) are used. HIS is a planar array of continuous metallic periodic cell surfaces able to suppress surface waves, which cause multipath interference and backward radiation in a narrow bandwidth near the cell resonance. Also, the image currents are reduced, and therefore the antenna can be placed near the HIS. We demonstrate that graphene is acting as a HIS surface in a very large bandwidth, from microwave to THz, suppressing the radiation leakages better than a metal.

Aldrigo, Martino; Costanzo, Alessandra [Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi” – DEI, University of Bologna, Viale del Risorgimento, 2, 40132 Bologna (Italy); Dragoman, Mircea [National Institute for Research and Development in Microtechnology (IMT), P.O. Box 38-160, 023573 Bucharest (Romania); Dragoman, Daniela [Department of Physics, University of Bucharest, P.O. Box MG-11, 077125 Bucharest (Romania)

2013-11-14

465

Accurate permittivity measurements for microwave imaging via ultra-wideband removal of spurious reflectors  

Technology Transfer Automated Retrieval System (TEKTRAN)

The use of microwave imaging is becoming more prevalent for detection of interior hidden defects in manufactured and packaged materials. In applications for detection of hidden moisture, microwave tomography can be used to image the material and then perform an inverse calculation to derive an estim...

466

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

467

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

468

CMOS Integrated Circuit Design for Ultra-Wideband Transmitters and Receivers  

E-print Network

radar, distance sensor, through wall radar to high speed, short distance communications. The CMOS integrated circuit is an attractive, low cost approach for implementing UWB technology. The improving cut-off frequency of the transistor in CMOS process...

Xu, Rui

2010-10-12

469

Performance of an Optimally Spaced PPM Ultra-Wideband System with Direct Sequence  

E-print Network

position modulation (PPM) for data modulation and direct sequence (DS) spreading for multiple access]. Time hopping (TH) has been found to be a good technique for multiple access [1]. Direct sequence (DS signaling for UWB systems with direct sequence spreading for multiple access and compare the performance

Liu, Huaping

470

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

E-print Network

microstrip quasi-horn antenna was optimized for short pulse transmission with respect to the input return loss and the pulse stretching effect. For signal detection in the signal processing stage, the background subtraction technique and B-scan data format...

Han, Jeongwoo

2006-08-16

471

Multi-pulse frequency shifted (MPFS) multiple access modulation for ultra wideband  

DOEpatents

The multi-pulse frequency shifted technique uses mutually orthogonal short duration pulses o transmit and receive information in a UWB multiuser communication system. The multiuser system uses the same pulse shape with different frequencies for the reference and data for each user. Different users have a different pulse shape (mutually orthogonal to each other) and different transmit and reference frequencies. At the receiver, the reference pulse is frequency shifted to match the data pulse and a correlation scheme followed by a hard decision block detects the data.

Nekoogar, Faranak (San Ramon, CA); Dowla, Farid U. (Castro Valley, CA)

2012-01-24

472

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

473

A Comprehensive Spatial-Temporal Channel Propagation Model for the Ultra-Wideband Spectrum 28 GHz  

E-print Network

, the FCC mask of -41.3 dBm/MHz EIRP in the spectrum 3.1­10.6 GHz translates to a maximum transmission power spatial-temporal model. Specifically, the main contributions of this paper are: · a frequency

474

Silicon-Based Ultra-Wideband Beamforming J. Roderick, H. Krishnaswamy, K. Newton, and H. Hashemi  

E-print Network

B BW Tapped Delay Trombone Line Variable Delay d L Incident Wave UWB Beamforming Array UWB Chip Size: 2.5mm x 0.9mm Broadband Variable Gain Amplifier MSB Delay Element Trombone 8-tap Variable 100 200 300 d Ideal Antennas Input Time (ps) Output Time (ps) Performance Result UWB delay resolution

Southern California, University of

475

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

E-print Network

of cross-couple transconductors multiplier ........................ 15 Fig 2.8 Differential pair with source degeneration ................................................. 16 Fig 2.9 Complementary differential pair with source degeneration... differential pairs with source degeneration as its input transconductor to convert the input voltage into current, then a programmable current mirror as its current gain stage to further amplify the current, and fixed load resistors to provide the linear...

Chen, Lin

2007-09-17

476

A 264 MHz CMOS Gm—C LPF for ultra-wideband standard  

NASA Astrophysics Data System (ADS)

A 264 MHz CMOS 4th Gm—C LPF target for the UWB standard is presented. The filter is designed by cascading two biquad cells. Compared with the previously published biquad cells, the biquad proposed here saves 1 transconductor, 3 CMFB networks and 2 capacitors. Benefiting from these merits, the power consumption and chip area of the 4th order UWB LPF are reduced dramatically without other characteristics being affected. The LPF is designed and fabricated with TSMC 0.18 ?m 1P6M CMOS technology. The implemented LPF achieves a power gain of -0.5 dB. The measured frequency response matches well with that of the simulating results. The core chip area is only 0.06 mm2, which has a wonderful advantage over those from similar work. The LPF excluding test-buffers dissipates a total current of 3 mA from the 1.8 V power supply.

Zhendong, Gao; Zhiqiang, Li; Hongkun, Li; Haiying, Zhang

2010-11-01

477

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

E-print Network

in literature that cancerous tissue in the breast exhibits separate dielectric properties than normal breast microwave antenna which must serve as an element in a sensor array for early-stage breast-cancer detection tomography, breast cancer detection, breast phantom, phantom fabrication #12;

Haykin, Simon

478

Small High Performance Ultra Wideband UHF Multipurpose Planar Antenna A. Babar* (1)  

E-print Network

. As the antenna is made of a simple microstrip structure [5], it can be embedded and integrated in various small, with no copper on the opposite side of the antenna structure of the PCB. The copper underneath the antenna system. As the antenna structure is not shorted with the ground plane like PIFA [7], it becomes less

Elsherbeni, Atef Z.

479

Ultra-Wideband Printed-Circuit Array Antenna for Medical Monitoring Applications  

E-print Network

structure for medical monitoring purpose is introduced. It consists of one single transmitting antenna would be to detect a person's heart and respiration rates [1] ­ [3]. Figure 1. UWB antenna structure of patients in elder care and health care facilities. The UWB antenna structure in Fig. 1 is designed

Bornemann, Jens

480

Planar half-disk antenna structures for ultra-wideband communications  

Microsoft Academic Search

Printed antennas are cheap, lightweight, easy to-fabricate with high precision, and adaptable to mass production. These features are desirable for both indoor and outdoor handheld UWB antenna applications. In this paper, we consider planar versions of the half-disk antenna with different feed structures. These versions are compared with respect to radiated pulse width (to get higher data throughput), pulse amplitude

Taeyoung Yang; William A. Davis

2004-01-01

481

An analog approach to interference suppression in ultra-wideband receivers  

E-print Network

of the interference, and includes a Least Means Squared (LMS) tuning scheme to maximize attenuation. The filter uses the Fast Fourier Transform (FFT) result for interference detection and discrete center frequency tuning of the filter. It was fabricated in a 0.18 Ã...

Fischer, Timothy W.

2007-09-17

482

ULTRA-UNIVERSAL MODELS  

Microsoft Academic Search

The concept of ultra-universal algebras in varieties is generalized to models of first order theories. Characterizations of theories which have ulta-universal models are found and general examples of ultra-universal models are investigated. In particular we show that a theory has an ultra-universal model iff it is consistent and its class of models satisfies the joint embedding property.

Colin Naturman; Henry Rose

1992-01-01

483

A Wireless Sensor Enabled by Wireless Power  

PubMed Central

Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network. PMID:23443370

Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

2012-01-01

484

A wireless sensor enabled by wireless power.  

PubMed

Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network. PMID:23443370

Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

2012-01-01

485

A 2.3?W wireless intraocular pressure\\/temperature monitor  

Microsoft Academic Search

We present the design of an ultra-low power, wireless capacitance\\/temperature sensing device for continuous intraocular pressure monitoring. The device is wirelessly powered and demonstrates a power consumption of 2.3?W at 1.5V during continuous reading. The chip converts both capacitance and temperature to frequency using a time-interleaved relaxation oscillator, which modulates RF backscatter to a reader for computation of measured samples.

Yi-Chun Shih; Tueng Shen; Brian Otis

2010-01-01

486

The wireless revolution  

Microsoft Academic Search

Current demand for and recent developments in wireless communication are described. Funding for wireless worldwide is examined. Tools and techniques used to characterize radio propagation are discussed, and some research results are presented

T. S. Rappaport

1991-01-01

487

Wideband adaptive beamforming to control time sidelobes and null depth  

NASA Astrophysics Data System (ADS)

High resolution radars use wide bandwidth waveforms to create images of unknown objects. In military systems, such radar images can be used for target identification and discrimination functions as long as the time sidelobes are kept low. However, the need for low sidelobes imposes constraints on the design of the radar in general, and the signal processing in particular. Furthermore, since military radars must operate in the presence of strong interference, wideband Adaptive Beam Forming techniques (ABF), such as Space-Time Adaptive Processing (STAP), are needed. This paper describes signal processing techniques for wideband digital radars that utilize stretch processing at each receiver. It analyzes the impact of stretch ABF techniques on time sidelobes, showing how sidelobe levels depend on the ABF architecture. It describes the impact of channel errors on time sidelobes and null depth, and proposes a digital filtering architecture for channel equalization, digital beamforming, and STAP.

Rabideau, Daniel J.; Parker, Peter

2003-08-01

488

Wideband direction finding via shielded gradient beamspace techniques  

NASA Astrophysics Data System (ADS)

Monopulse techniques have been used for over 50 years in the radar community to estimate the direction of arrival (DOA) of incoming echoes. In recent years, a variant of the monopulse technique has been developed, termed the shielded gradient technique, which allows DOA estimation for signals of arbitrary bandwidth. The technique maps the array-output M-vector into a frequency-invariant B-dimensional beamspace. The work presented here describes the shielded gradient beamspace model in its higher-order form, and develops wideband DOA estimation algorithms analogous to the narrow-band MUSIC, root-MUSIC, and ESPRIT algorithms. The performance of these new algorithms is studied through simulation and application to measured, in-water sonar data. They are also compared via simulation to existing wideband DOA estimation algorithms. [Work supported by the Internal Research and Development Program under Contract No. FEE-800.

Brudner, Terry J.; Henderson, Terry L.

2003-10-01

489

Direction Dependent Effects In Widefield Wideband Full Stokes Radio Imaging  

NASA Astrophysics Data System (ADS)

Synthesis imaging in radio astronomy is affected by instrumental and atmospheric effects which introduce direction dependent gains.The antenna power pattern varies both as a function of time and frequency. The broad band time varying nature of the antenna power pattern when not corrected leads to gross errors in full stokes imaging and flux estimation. In this poster we explore the errors that arise in image deconvolution while not accounting for the time and frequency dependence of the antenna power pattern. Simulations were conducted with the wideband full stokes power pattern of the Very Large Array(VLA) antennas to demonstrate the level of errors arising from direction-dependent gains. Our estimate is that these errors will be significant in wide-band full-pol mosaic imaging as well and algorithms to correct these errors will be crucial for many up-coming large area surveys (e.g. VLASS)

Jagannathan, Preshanth; Bhatnagar, Sanjay; Rau, Urvashi; Taylor, Russ

2015-01-01

490

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

...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...

2012-10-01

491

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

492

UMTS\\/IMT2000 based on wideband CDMA  

Microsoft Academic Search

The UMTS terrestrial radio access is based on wideband 4.096 Mchip\\/s DS-CDMA technology. UTRA will be connected to an evolved GSM core network for both circuit and packet services. A merger between ETSI\\/Europe and ARIB\\/Japan based on W-CDMA, a GSM core network, and a common frequency allocation according to the ITU Recommendation of 2 GHz makes a global IMT-2000 standard

Erik Dahlman; Bjorn Gudmundson; Mats Nilsson; A. Skold

1998-01-01

493

Wideband probe-fed circularly polarised circular loop antenna  

E-print Network

of the printed loops was chosen to be w ¼ 4r0. The antenna was initially designed using a method-of-moment based software, NEC 1.1, and optimised by a full-wave (transmission-line matrix method based) design toolWideband probe-fed circularly polarised circular loop antenna R.L. Li, J. Laskar and M.M. Tentzeris

Tentzeris, Manos

494

A Wideband Circularly Polarized Patch Antenna with Conical Radiation Pattern  

Microsoft Academic Search

A circularly polarized conical-beam patch antenna that employs a hybrid feeding mechanism for wideband operation is presented in this paper. It is implemented through using a pair of L-probes and apertures, which are connected by the feeding network, to excite the circular patch in orthogonal directions. The patch is supported by two plastic posts of 0.084 lambda0 height in the

K. L. Lau; K. M. Luk

2005-01-01

495

A Wideband SMM Antenna with Gap and Dielectric Loadings  

Microsoft Academic Search

A wideband four-arm spiral mode microstrip (SMM) antenna, which is loaded by dielectric and gap, is introduced in this paper. This antenna, which operates at mode 0, uses a shallow back cavity to suppress back radiation. Gap-loading and dielectric-loading are used to decrease the voltage standing wave ratio (vswr) of the antenna. A capacitive gap is introduced by a metal

Zhang Feng; Ji Yicai; Fang Guangyou; Ju Hanji

2011-01-01

496

Compact wide-band polymer wavelength-division multiplexers  

Microsoft Academic Search

Wide-band wavelength-division multiplexers (WDMs) have been developed for applications in short-haul and satellite communications. Device designs based on Mach-Zehnder interferometers (MZIs) and arrayed waveguide gratings (AWGs) have been fabricated using AlliedSignal Inc. low-loss acrylate polymer materials. Low channel-counts and channel separations of 5-30 nm result in compact devices with relaxed processing tolerances, thus minimizing the cost and increasing the yields

J.-F. Viens; C. L. Callender; J. P. Noad; L. Eldada

2000-01-01

497

Iterative direction-of-arrival estimation with wideband chirp signals  

NASA Astrophysics Data System (ADS)

Amin et. al. recently developed a time-frequency MUSIC algorithm with narrow band models for the estimation of direction of arrival (DOA) when the source signals are chirps. In this research, we consider wideband models. The joint time-frequency analysis is first used to estimate the chirp rates of the source signals and then the DOA is estimated by the MUSIC algorithm with an iterative approach.

Wang, Genyuan; Xia, Xiang-Gen; Chen, Victor C.

1999-11-01

498

Generalized architecture for DOA estimation for wideband/narrowband sources  

NASA Astrophysics Data System (ADS)

The high-resolution direction-of-arrival (DOA) estimation algorithms are studied to develop architecture for real time applications. Methods for DOA estimation for wideband sources proposed by Buckley and Griffiths and MUSIC algorithm for narrowband sources proposed by Schmidt have been selected for hardware implementation. These algorithms have been simplified and generalized into one common programmable algorithm. It is then parallelized and is executed in a pipelined fashion. A parallel architecture has been designed for this generalized algorithm.

Tabar, R.; Jamali, Mohsin M.; Kwatra, S. C.; Djouadi, A. H.

1993-10-01

499

A wideband orthogonal-mode junction using ridged sectoral waveguides  

Microsoft Academic Search

A wideband orthogonal-mode junction (OMJ) using a quad-ridged circular coaxial waveguide and four single-ridged sectoral waveguides is described. The new structure is used for extracting a wide lower band signal from a coaxial dual-band feed. Theoretical results show that the broadband incoming signal in the quad-ridged coaxial waveguide can be coupled to four single-ridged sectoral waveguides with low reflection. The

Henry Z. Zhang

2002-01-01

500

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