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1

Minimizing average network delay for ultra-wideband wireless networks  

Microsoft Academic Search

Ultra-wideband wireless (UWB) may provide the physical layer for high capacity personal area networks in the future. Certain characteristics of the wireless links possible using this technology give rise to properties not seen with other wireless technologies. Two such properties are long synchronization times for link establishment and the ability to change individual link capacities by choosing PN codes of

Christopher S. Taggart; Yannis Viniotis; Mihail L. Sichitiu

2005-01-01

2

Packet Scheduling with Fairness Adaptation in Ultra Wideband Wireless Networks  

Microsoft Academic Search

Ultra-wideband (UWB) transmission is an emerging wireless technology, and medium access control (MAC) with quality of service (QoS) provisioning is essential to coordinate the access among competing devices in UWB-based wireless networks. In this paper, we study the exclusive region concept (which was previously proposed) to determine the active set of senders at a time. We find out that, different

Hai Jiang; Weihua Zhuang

3

Measurement and characterization of ultra-wideband wireless interconnects within active computing systems  

Microsoft Academic Search

This paper presents experimental measurements of ultra-wideband (UWB) wireless interconnects within an operational computer system chassis. Using an impulse-radio ultra-wideband (IR-UWB) 3-5GHz transceiver, this paper analyzes and verifies the implementation of high-bandwidth wireless communications within an enclosed, heavy multipath, metallic environment such as a computer server chassis. Bit-error-rate (BER) and recovered clock jitter were measured at various positions within the

Sirikarn Woracheewan; Changhui Hu; Rahul Khanna; Jay Nejedlo; Huaping Liu; Patrick Chiang

2011-01-01

4

A CMOS low-noise amplifier with impedance feedback for ultra-wideband wireless receiver system  

Microsoft Academic Search

In this paper, a CMOS low-noise amplifier (LNA) is designed for ultra-wideband (UWB) wireless receiver system. The design consists of a wideband input impedance matching network, a cascoded amplifier with shunt-peaked load, a RLC-impedance feedback loop and an output buffer for measurement purpose. It is fabricated in TSMC 0.18 um standard RF CMOS process. The LNA gives 11.5 dB maximum

Zhe-Yang Huang; Che-Cheng Huang; Chun-Chieh Chen; Chung-Chih Hung; Christina F. Jou

2008-01-01

5

Ultra-wideband Communications  

Microsoft Academic Search

Many applications in wireless communications often require short-range systems capable of rapidly collecting data and transmitting it reliably. Commercial communication systems operate in fixed frequency bands and are easily detectable and are prone to jamming by the enemy, among other shortcomings. The new ultra-wideband (UWB) communications system in the 3.1 to 10 GHz band is of significant interest to a

K Waltjen; C Romero; S Azevedo; F Dowla; A Spiridon; D Benzel; P Haugen

2004-01-01

6

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

7

Performance evaluation for WiMedia Ultra-wideband simultaneous transmission with wireless LAN over cable and fiber  

Microsoft Academic Search

This paper investigates the performances of the WiMedia Ultra-wideband signal simultaneously transmitted with the wireless local area nework signals using either coaxial cables or radio-over-fiber links. Error vector magnitude and packet error rate were carried out to evaluate the system characteristics.

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

2008-01-01

8

Ultra-wideband Communications  

SciTech Connect

Many applications in wireless communications often require short-range systems capable of rapidly collecting data and transmitting it reliably. Commercial communication systems operate in fixed frequency bands and are easily detectable and are prone to jamming by the enemy, among other shortcomings. The new ultra-wideband (UWB) communications system in the 3.1 to 10 GHz band is of significant interest to a number of Lawrence Livermore National Laboratory (LLNL) programs including the Nonproliferation, Arms Control, and International Security (NAI) Directorate. Ultra-Wideband (UWB) technology has received a significant degree of attention from communications industry since the Federal Communications Commission (FCC) rulings in February 2002. According to FCC, UWB signals have fractional bandwidth (B{sub f}) of 20% or larger at -10 dB cut-off frequencies, with minimum bandwidth of 500 MHz. Unlike traditional communication systems, UWB systems modulate carrier-less, short-duration (picosec to nanosec) pulses to transmit and receive information. A number of programmatic problems at LLNL, particularly in the NAI and other national security Directorates, require collecting information from multiple sensors distributed over a local area. The information must be collected covertly and by wireless means. The sensors produce data using low power devices and the communication link must operate in severe multipath environments over tens of meters; often the links must be channelized to handle multiple sensors. The communications links between these sensors is a critical issue in the development of LLNL programs to demonstrate distributed sensor network performance in real-time. In summary, such systems must be robust; have a low probability of detection and intercept; employ low-power, small-size hardware; and interface easily with other systems for analysis or to establish long-distance links. The purpose of this work was to develop a new UWB radio-frequency (RF) communications system for the UWB RF band. In this project we addressed the need for robust UWB communication systems with low-power, small-size sensor communication hardware. Our research results have successfully addressed these issues and we developed UWB radios and interfaced these radios with repeater radios for longer distance links. In particular, research and development challenges included signal processing and communication design problems, including developing novel UWB modulation and demodulation schemes, link budget analysis for ultra-wideband signals, multipath mitigation, short-pulse signal synchronization, and building real working radios. We have had a significant degree of success in solving these technical challenges. As a result, several programmatic efforts have spun off from our R&D work in FY04.

Waltjen, K; Romero, C; Azevedo, S; Dowla, F; Spiridon, A; Benzel, D; Haugen, P

2004-02-06

9

Effective Packet Scheduling with Fairness Adaptation in Ultra Wideband Wireless Networks  

Microsoft Academic Search

The inherent spread spectrum nature in ultra- wideband (UWB) communications can support simultaneous transmissions. Two nearby transmissions do not collide, but rather generate interference to each other, thus requiring dif- ferent coordination mechanisms from those in the single-channel case. This research is to design effective packet scheduling to determine when, where, and how to allow simultaneous transmissions, and how to

Hai Jiang; Weihua Zhuang

2006-01-01

10

Neuromorphic interconnects using Ultra Wideband radio  

Microsoft Academic Search

We present the architecture and testing of an address event representation (AER) wireless link that uses ultra wideband (UWB) radio as the physical layer. The wireless protocol layers from high to low level are: AER events, asynchronous handshaking, PRN coding, and UWB transmission. The top three layers are implemented in digital logic in an FPGA, while the UWB physical layer

Andrew Cassidy; Zhaonian Zhang; Andreas G. Andreou

2008-01-01

11

CMOS low-noise amplifier with shunt-peaking load for group 1?3 MB-OFDM ultra-wideband wireless receiver  

Microsoft Academic Search

In this paper, a CMOS low-noise amplifier (LNA) is designed for ultra-wideband (UWB) wireless receiver system. The design consists of a wideband input impedance matching network, two stage cascode amplifiers with shunt-peaking load and an output buffer for measurement purpose. It was fabricated in UMC 0.18 mum standard RF CMOS process. The LNA provides 14.1 dB maximum power gain between

Zhe-Yang Huang; Che-Cheng Huang; Chun-Chieh Chen; Chung-Chih Hung; Christina F. Jou

2008-01-01

12

Ultra-wideband generators.  

National Technical Information Service (NTIS)

High-power ultra-wideband pulses with equivalent center frequences of 10 GHz require picosecond switching times of high electric fields. We are developing a high-pressure gas switch that is designed to store several joules of energy. The switch has an ove...

P. A. Pincosy P. Poulsen J. J. Morrison

1991-01-01

13

Ultra-wideband generators  

Microsoft Academic Search

High-power ultra-wideband pulses with equivalent center frequences of 10 GHz require picosecond switching times of high electric fields. We are developing a high-pressure gas switch that is designed to store several joules of energy. The switch has an overvoltaged gap that is pulse charged to operating voltages before the electron avalanche causes the voltage to collapse. Depending on the gas

P. A. Pincosy; P. Poulsen; J. J. Morrison

1991-01-01

14

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

15

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

16

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

17

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

18

Ultra-wideband generators  

NASA Astrophysics Data System (ADS)

High-power ultra-wideband pulses with equivalent center frequences of 10 GHz require picosecond switching times of high electric fields. We are developing a high-pressure gas switch that is designed to store several joules of energy. The switch has an overvoltaged gap that is pulse charged to operating voltages before the electron avalanche causes the voltage to collapse. Depending on the gas pressure (designed for up to 100 atm) and the electric field, the voltage collapse time can be hundreds of picoseconds down to a few picoseconds. Uniform development of the avalanche is initiated by photoionization from a bare spark or an ultraviolet laser. The pulse-power charging system is designed to charge the transmission line in a few nanoseconds. The stored energy that would flow as a post-pulse component is to be minimized. Tests of the repetition rate for the switch are part of the development. Data in this paper indicate the achieved gap electric field, the voltage collapse time, and the launched pulse power and energy down transmission line.

Pincosy, P. A.; Poulsen, P.; Morrison, J. J.

1991-12-01

19

Medical applications of the Ultra Wideband technology  

Microsoft Academic Search

In this paper the application of the Ultra Wideband technology in the medical field is investigated. This is done by presenting a mathematical description of the Ultra Wideband medical scenario and a model of the human body. Besides, the requirements of antennas for Ultra Wideband medical applications are discussed. The most important existing applications of the UWB technology in the

Elena Pancera

2010-01-01

20

An integrated 3.1-5.1 GHz pulse generator for ultra-wideband wireless localization systems  

Microsoft Academic Search

This paper presents an implementation of an integrated Ultra-wideband (UWB), Binary-Phase Shift Keying (BPSK) Gaussian modulated pulse generator. VCO, multiplier and passive Gaussian filter are the key components. The VCO provides the carrier frequency of 4.1 GHz, the LC Gaussian filter is responsible for the pulse shaping in the baseband. Multiplying the baseband pulse and the VCO frequency shifts the

X. Fan; G. Fischer; B. Dietrich

2006-01-01

21

A practical wireless charging system based on ultra-wideband retro-reflective beamforming  

Microsoft Academic Search

Numerous portable electronic devices (such as laptops, cell phones, digital cameras, and electric shavers) rely on rechargeable batteries and must be routinely charged by the line power. A wireless charging technique capable of delivering electromagnetic energy to these portable devices would make them tether free and \\

Huiqing Zhai; Helen K. Pan; Mingyu Lu

2010-01-01

22

State of arts in ultra wideband (UWB) wireless technology and global harmonization  

Microsoft Academic Search

As a center of mobile multimedia of the 21st century, it is very much looking forward to explosion of R&D and business of various wireless communication systems. In order to maintain advancement of communications and its related industries in Japan, there is a demand to keep creating new high technologies and theories and to educate a high level of experts

Ryuji KOHNO

2004-01-01

23

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

24

Ultra-wideband (UWB) geolocation in NLOS multipath fading environments  

Microsoft Academic Search

Geolocation aware services are becoming attractive with the deployment of next generation wireless networks and broadband multimedia wireless networks (i.e. ubiquitous and pervasive computing) especially in indoor and campus areas. In order to construct an ad-hoc network the upcoming ultra-wideband (UWB) radio technology holds great promise for revolutionizing wireless communications especially in indoor environments (office, residential, industrial). The two proposals

R. A. Saeed; S. Khatun; B. M. Ali; M. A. Khazani

2005-01-01

25

An Ultra-Wideband CMOS Receiver Front-End  

Microsoft Academic Search

A CMOS receiver front-end for ultra-wideband (UWB) wireless communications based on multi-band OFDM -Alliance (MBOA) \\/ WiMedia standard proposal is presented. Employing a direct conversion architecture, the RF front-end chip integrates a single-ended wideband low-noise amplifier (LNA) and two double-balanced downconversion mixers. To reduce power consumption, the conversion of single ended LNA output to differential is embedded in the RF

Bo Shi; Michael Yan; Wah Chia

2007-01-01

26

An ultra-wideband CMOS receiver front-end  

Microsoft Academic Search

A CMOS receiver front-end for ultra-wideband (UWB) wireless communications based on multi-band OFDM alliance (MBOA)\\/WiMedia standard proposal is presented. Employing a direct conversion architecture, the RF front-end chip integrates a single-ended wideband low-noise amplifier (LNA) and two double-balanced downconversion mixers. To reduce power consumption, the conversion of single ended LNA output to differential is embedded in the RF transconductance circuit

Bo Shi; M. Y. W. Chia

2007-01-01

27

Noncoherent ultra-wideband systems  

Microsoft Academic Search

The need for low-complexity devices with low-power consumption motivates the application of suboptimal noncoherent ultra-wideband (UWB) receivers. This article provides an overview of the state of the art of recent research activities in this field. It introduces energy detection and autocorrelation receiver front ends with a focus on architectures that perform the initial signal processing tasks in the analog domain,

Klaus Witrisal; Geert Leus; Gerard Janssen; Marco Pausini; Florian Troesch; Thomas Zasowski; Jac Romme

2009-01-01

28

Ultra-wideband range estimation: Theoretical limits and practical algorithms  

Microsoft Academic Search

The high time resolution of ultra-wideband (UWB) signals enables wireless devices to perform accurate range estimation. In order to realize UWB systems with accurate ranging capabilities, both theoretical limits on range estimation and practical algorithms that approach those limits should be investigated. This paper provides a survey of various UWB ranging algorithms and discusses their performance and complexity tradeoffs. In

Ismail Guvenc; Sinan Gezici; Zafer Sahinoglu

2008-01-01

29

An integrated 3.1-5.1 GHz pulse generator for ultra-wideband wireless localization systems  

NASA Astrophysics Data System (ADS)

This paper presents an implementation of an integrated Ultra-wideband (UWB), Binary-Phase Shift Keying (BPSK) Gaussian modulated pulse generator. VCO, multiplier and passive Gaussian filter are the key components. The VCO provides the carrier frequency of 4.1 GHz, the LC Gaussian filter is responsible for the pulse shaping in the baseband. Multiplying the baseband pulse and the VCO frequency shifts the pulse to the desired center frequency. The generated Gaussian pulse ocupppies the frequency range from 3.1 to 5.1 GHz with the center frequency at 4.1 GHz. Simulations and measured results show that this spectrum fulfills the mask for indoor communication systems given by the FCC (Federal Communications Commission, 2002). The total power consumption is 55 mW using a supply voltage of 2.5 V. Circuits are realized using the IHP 0.25 ?m SiGe:C BiCMOS technology.

Fan, X.; Fischer, G.; Dietrich, B.

2006-09-01

30

Experimental and theoretical investigation of the multiband OFDM ultra-wideband radio over multimode fiber transmission  

Microsoft Academic Search

A combined wireless and optical channel for multiband orthogonal frequency division multiplexing (MB OFDM) ultra-wideband (UWB) radio transmission has been investigated both experimentally and theoretically. The channel consists of a directly modulated vertical cavity surface emitting laser (VCSEL), wireless channel, ultra-wideband (UWB) antenna, multimode optical fiber (MMF) and a p-i-n diode as a photodetector (PD). It has been shown both

Y. Ben Ezra; B. I. Lembrikov; M. Ran; A. Leibovich; E. Borohovich

2008-01-01

31

A multibanded system architecture for ultra-wideband communications  

Microsoft Academic Search

The FCC ruling in 2002 allowing for the unlicensed deployment of ultra-wideband (UWB) devices for communications purposes in the 3.1-10.6 GHz band has sparked great interest in the industry. In particular, the IEEE 802.15.3a task group is currently developing a standard for high-rate, short-range wireless communication systems that is expected to use UWB technology. One of the main challenges for

Jefiey R. Foerster; V. Somayazulu; Sumit Roy

2003-01-01

32

UCom: Ultra-wideband Communications in Harsh Propagation Environments  

SciTech Connect

LLNL has developed an ultra-wideband (UWB) system that provides unique, through-the-wall wireless communications in heavy metallic and heavy concrete indoor channels. LLNL's UWB system is the only available wireless communications system that performs successfully and reliably in facilities where conventional narrowband communications usually fail due to destructive reflections from multiple surfaces. These environments include: cargo ships and reinforced, heavy concrete buildings. LLNL's revolutionary system has applications for the military, as well as commercial indoor communications in multistory buildings, and cluttered industrial structures.

Nekoogar, F

2007-03-14

33

Modified Chirp Waveforms for Cognitive Ultra Wideband Radio - Work in Progress  

Microsoft Academic Search

Cognitive Radio (CR) is an intelligent wireless communication system which is aware of its environment and can adjust its spectrum to utilize the frequency holes in the wireless environment. By this way, a highly efficient utilization of the radio resource can be achieved. We propose a novel CR modulation method that is based on the Ultra-wideband (UWB) chirp waveform in

Hanbing Shen; Weihua Zhang; Kyung Sup Kwak

2007-01-01

34

Ultra-wideband phased antenna arrays  

Microsoft Academic Search

A new type of ultra-wideband nonuniformly spaced antenna array is designed. So-called modified FCAA can work at a frequency band of up to 10:1. Under multiple frequency change the FCAA ensures the uniqueness of the main lobe in the space, constancy of the peak sidelobe level and directivity

Bohdan V. Koval

2001-01-01

35

An overview of ultra-wideband technique  

Microsoft Academic Search

In recent years, ultra-wideband (UWB) technique was considered as a candidate for short range high data rate communications with precise location and positioning ability at the order of centimeter, and many contributions have been presented by researchers, which promoted the development of UWB technique. In this paper, the state of the art and new development of UWB technique was presented

Sha Xue-jun; Wu Xuan-li; Zhang Qin-yu; Wang Yang

2010-01-01

36

Ultra-Wideband (UWB) Bandpass Filter With Embedded Band Notch Structures  

Microsoft Academic Search

A compact ultra-wideband (UWB) bandpass filter (BPF) with narrow notched (rejection) band in the UWB passband realized on a microstrip line is implemented and presented in this letter for use in wireless communication applications within the unlicensed UWB range set by the Federal Communications Commission (FCC). The filter consists of five short-circuited stubs separated by nonredundant connecting lines in order

Hussein Shaman; Jia-Sheng Hong

2007-01-01

37

Low-complexity training for rapid timing acquisition in ultra wideband communications  

Microsoft Academic Search

Rapid timing acquisition with low complexity constitutes a major challenge in realizing the high potential ultra wideband (UWB) technology promises for indoor wireless communications. We design and test such a timing acquisition algorithm based on training symbols. Relying on a judiciously designed preamble, our algorithm achieves clock synchronization at the receiver using simple integrate-and-dump operations over the symbol duration. Analysis

Liuqing Yang; Georgios B. Giannakis

2003-01-01

38

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

39

A Novel Framework for Medium Access Control in Ultra-Wideband Ad Hoc Networks  

Microsoft Academic Search

Ultra-wideband (UWB) communication is becoming an important technology for future Wireless Personal Area Networks (WPANs). A critical challenge in UWB system design is that a receiver usually needs tens of micro-seconds or even tens of milliseconds to synchronize with transmitted signals, known as timing acquisition problem. Such a long synchronization time will cause significant overhead, since the data rate of

Kejie Lu; Dapeng Wu; Yuguang Fang

2005-01-01

40

A Low-Power High-Speed Ultra-Wideband Pulse Radio Transmission System  

Microsoft Academic Search

We present a low-power high-speed ultra-wideband (UWB) transmitter with a wireless transmission test platform. The system is specifically designed for low-power high-speed wireless implantable biosensors. The integrated transmitter consists of a compact pulse generator and a modulator. The circuit is fabricated in the 0.5-mum silicon-on-sapphire process and occupies 420 mum times 420 mum silicon area. The transmitter is capable of

Wei Tang; Eugenio Culurciello

2009-01-01

41

Ultra-wideband sensing: The road to new radar applications  

Microsoft Academic Search

Research on ultra-wideband topics started about 50 to 60 years ago driven by needs in radar and communication technology as well as to emulate EMPs of nuclear explosions. Meanwhile, ultra-wideband sensing opens new perspectives for radar applications. Small and cost effective devices, high resolution and sensitivity, as well as low exposition by radio waves will give this radar technology access

J. Sachs

2010-01-01

42

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

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. 15 figs.

McEwan, T.E.

1994-11-01

44

MAC protocols for wideband wireless local access: evolution toward wireless ATM  

Microsoft Academic Search

The wireless local area network (WLAN) and wireless ATM are emerging technologies for wideband wireless local access. Two standards, IEEE 802.11 and ETSI HIPERLAN type 1, are currently available for WLAN; the standardization process of wireless ATM, involving, among others, the wireless ATM Group of the ATM Forum and the broadband radio access networks project of the ETSI, is ongoing

GIUSEPPE ANASTASI; LUCIANO LENZINI; ENZO MINGOZZI; ANDREAS HETTICH; A. Kramling

1998-01-01

45

Compact Ultra-wideband Microstrip Antenna with Metamaterials  

NASA Astrophysics Data System (ADS)

An improved compact ultra-wideband (UWB) microstrip antenna with metamaterials is proposed. The total size is slightly reduced and the measured impedance bandwidth operates from 3.84 to 22.77 GHz for a return loss of less than -10 dB. Compared with the original patch antenna, the bandwidth of this antenna is about six times broader. Moreover, the antenna has an average gain of 6.2 dB, which is 1.2 dB larger than the original one. Both strong radiation in the horizontal direction and practical characteristics are observed. Thus, this antenna would have some specific applications for UWB wireless communications in the future.

Xiong, Han; Hong, Jin-Song; Zhu, Qing-Yi; Jin, Da-Lin

2012-11-01

46

Design and Development of Ultra Wideband Antennas for Various Applications  

Microsoft Academic Search

The paper summarizes results of investigations, design and development of ultra wideband antennas carried out during the last ten years in the laboratory of antennas and telecommunication systems of NTUU (\\

F. Dubrovka; S. Martynyuk

2006-01-01

47

Compressed Sensing Based Ultra-Wideband Communication System.  

National Technical Information Service (NTIS)

Sampling is the bottleneck for ultra-wideband (UWB) communication. Our major contribution is to exploit the channel itself as part of compressed sensing, through waveformbased pre-coding at the transmitter. We also have demonstrated a UWB system baseband ...

B. M. Sadler P. Zhang R. C. Qiu Z. Hu

2009-01-01

48

A MULTI-BANDED SYSTEM ARCHITECTURE FOR ULTRA-WIDEBAND COMMUNICATIONS  

Microsoft Academic Search

The FCC ruling in 2002 allowing for the unlicensed deployment of ultra-wideband (UWB) devices for communications purposes in the 3.1-10.6 GHz hand has sparked great interest in the industry. In particular, the IEEE 802.15.3a task group is currently developing a standard for high-rate, short-range wireless communication systems that is expected to use UWB technology. One of the main challenges for

Jefiey R. Foerster; V. Somayazulu; Sumit Roy

2009-01-01

49

A low-power high-speed ultra wideband pulse radio system  

Microsoft Academic Search

We present a low-power high-speed ultra-wideband (UWB) pulse radio transmission test platform. The transmitter circuit is fabricated on the Peregrine semiconductors 0.5 micron silicon-on-sapphire (SOS) CMOS process and packaged in a DIP16 package. 12.5 Mbps data rate of wireless transmission is achieved. The power consumption of the transmitter is 10 mW when the pulse rate is 90 MHz. The core

Wei Tang; Eugenio Culurciello

2009-01-01

50

Timing Acquisition with Noisy Template for Ultra-Wideband Communications in Dense  

Microsoft Academic Search

Timing acquisition is critical to enabling the poten- tial of ultra-wideband radios in high-speed, short-range indoor wireless networking. An effective timing acquisition method should not only operate at a low sampling rate to reduce implementation complexity and synchronization time, but also be able to collect sufficient signal energy in order to operate in a rea- sonable transmit-SNR regime. Energy capture

Zhi Tian; Lin Wu

51

Two-Step Time of Arrival Estimation for Pulse-Based Ultra-Wideband Systems  

Microsoft Academic Search

In cooperative localization systems, wireless nodes need to exchange accurate position-related information such as time-of-arrival (TOA) and angle-of-arrival (AOA), in order to obtain accu- rate location information. One alternative for providing accurate position-related information is to use ultra-wideband (UWB) signals. The high time resolution of UWB signals presents a potential for very accurate positioning based on TOA estimation. However, it

Sinan Gezici; Zafer Sahinoglu; Andreas Molisch; Hisashi Kobayashi; H. Vincent Poor

2009-01-01

52

A Digital Polar Amplifier for Ultra-Wideband with dynamic element matching  

Microsoft Academic Search

Digital polar architectures have been employed on wireless standards with low fractional bandwidths (FB) and high power requirements. To study if they can be adopted for low-power and high FB requirements, we propose a low-voltage 3-bit Digital Polar Amplifier (DPA) for Ultra-Wideband (FB of 15.4%). The DPA comprises 7 parallel RF amplifiers driven by the RF phase-modulated component and 7

Kwang-Hwee Seah; Michael Yan-Wah Chia

2010-01-01

53

Non-data aided timing acquisition of ultra-wideband transmissions using cyclostationarity  

Microsoft Academic Search

Low-complexity rapid timing acquisition constitutes a major challenge in realizing the high potential that ultra-wideband (UWB) wireless technology promises for indoor communications. We derive and test two such timing acquisition algorithms which capitalize on the cyclostationarity that is naturally present in UWB transmissions. Our novel schemes are blind, they do not require multiple antennas or oversampling, and rely on frame-rate

Liuqing Yang; Zhi Tian; Georgios B. Giannakis

2003-01-01

54

A Simple Ultra-Wideband Wake-up Scheme for SemiActive Sensor Nodes  

Microsoft Academic Search

Ultra-wideband impulse radio (UWB-IR) merges low complexity system design with good localization capabilities enabling low-data-rate\\/location-tracking (LDR\\/LT) sensor network design. However power consumption of the sensor nodes is a fundamental problem. Therefore, a simple wake-up scheme for asymmetric network topologies is investigated, where a static wireless backbone communicates with many semi-active sensor nodes. At sensor side only a low power wake-up

Florian Troesch; A. Wittneben

2006-01-01

55

Effects of location and room height on ultra wideband propagation around the human body  

Microsoft Academic Search

Radio propagation has been intensively studied for recently-emerging wireless body area network (WBAN) applications. To facilitate high-speed WBAN, ultra wideband (UWB) is a promising technology because of its low power consumption and anti-multipath capabilities. The authors have focused UWB (typically 3.1 to 10.6 GHz) propagation measurements around the human body in various environments. A new UWB propagation loss model was

M. Koiwai; T. Kobayashi

2011-01-01

56

A 3?5 GHz low-complexity ultra-wideband CMOS RF front-end for low data-rate WPANs  

Microsoft Academic Search

This paper presents a 3-5 GHz ultra-wideband radio front-end for low data-rate wireless personal area network applications. The circuit, implemented in a 90-nm CMOS technology, includes a carried-based ultra-wideband transmitter, a sub-optimal coherent down-converter and a low-power LO signal generator. Thanks to a pseudo-Gaussian pulse generator, the transmitter is able to run up to 500 Mpps satisfying the FCC mask

Marco Cavallaro; Alessandro Italia; Giuseppina Sapone; Giuseppe Palmisano

2008-01-01

57

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

58

A survey of antennas for ultra-wideband applications  

NASA Astrophysics Data System (ADS)

The usage of ultra-wideband (UWB) technology is growing in many communication systems such as radar systems, communication and measurement systems and imaging systems mainly because unlike the other wireless technologies UWB is not restricted to using a narrow waveband and it has high speed data rate. The large transmission bandwidth makes UWB-based electronic device resistive to interferences and gives immunity against getting detected. Typical operational frequency range of the UWB devices varies from few 100s MHz to 10 GHz. However, the most popular UWB devices are designed to operate between 1-3 GHz. This paper presents an overview of different types of commercially available antennas suitable for UWB applications. The paper begins with the basics of understanding of antennas properties. Next, it discusses the main antenna characteristics like: radiation pattern (directional or omni-directional), gain, bandwidth, size, etc for different UWB applications and explains criterions for quantitative and qualitative performance measure of the antennas. The antennas covered in this paper include: TEM Horn, Folded horn, Dipole, Planner Fat Dipole, Cross Dipole, Rolled Dipole, UWB dielectric, Bowtie, Wire Bowtie, etc. This paper describes the pros and cons of each antenna and highlights the application areas of each antenna. Lastly, this paper summaries the important characteristics of the antennas and presents several promising directions for future enhancement of UWB antenna systems.

Sarfaraz, Maysam; Shirkhodaie, Amir

2008-05-01

59

A PPM Gaussian Monocycle Transmitter for Ultra-Wideband Communications  

Microsoft Academic Search

A Gaussian pulse generator incorporating a pulse position modulator for use in an impulse radio ultra- wideband system is described. The pulse generator is preceded by a programmable pulse-position modulator and comprises of a cascade of complex first-order systems, which, in turn, are made up of differential pairs employing partial positive feedback. The resulting PPM Gaussian pulse generator is designed

Sumit Bagga; Wouter A. Serdijn; John R. Long

60

Evaluation of an Ultra-Wideband Propagation Channel  

Microsoft Academic Search

This paper describes the results of an ultra- wideband (UWB) propagation study in which arrays of propagation measurements were made. After a description of the propagation measurement technique, an approach to the spatial and temporal decomposition of an array of mea- surements into wavefronts impinging on the receiving array is presented. Based on am odification of the CLEAN algo- rithm,

J. M. Cramer; R. A. Scholtz; M. Z. Win

2002-01-01

61

Ultra-wideband communication using hybrid matched filter correlation receivers  

Microsoft Academic Search

For ultra-wideband (UWB) communication, Rake receivers using matched filter detection show the best performance but they are complex to realize due to the inherent channel estimation problem and combining problem. Transmitted reference schemes, on the other hand, allow for a less complex receiver structure that is able to combine the energy from different multipath components without channel estimation. These schemes,

Fredrik Tufvesson; Andreas F. Molisch

2004-01-01

62

State of the art in ultra-wideband antennas  

Microsoft Academic Search

Ultra wide-band (UWB) technology is one of the most promising solutions for future communication systems due to its high-speed data rate and excellent immunity to multipath interference. In this context, the UWB antenna design plays a unique role because it behaves like a band pass filter and reshapes the spectra of the pulses, so it should be designed to avoid

M. A. Peyrot-Solis; G. M. Galvan-Tejada; H. Jardon-Aguilar

2005-01-01

63

An ultra-wideband monocycle pulse generator with good performance  

Microsoft Academic Search

A new ultra-wideband monocycle pulse generator with good performance is designed and demonstrated. The pulse generator circuits employ SRD(step recovery diode), Schottky diode, and simple RC coupling and decoupling circuit, and are completely fabricated on the planar microstrip structure, which have the characteristic of low cost and small size. Through SRD modeling, the accuracy of the simulation is improved, which

Zhong Li; Xin-Xin Lv; Yun-Fu Long; Tian Qin

2011-01-01

64

Ultra wideband DSSS for multiple access communications using antipodal signaling  

Microsoft Academic Search

Ultra wideband (UWB) technology is characterized by transmitting extremely short duration radio impulses. To improve its multiple access (MA) capability, UWB technology can be combined with traditional spread spectrum techniques. So far, much of the research has focused on employing time hopping spread spectrum with impulse radio using pulse position modulated (PPM) signals. In this paper, we outline the attractive

N. Boubaker; K. B. Letaief

2003-01-01

65

The low dispersion coaxial cavity as an ultra wideband antenna  

Microsoft Academic Search

A coaxial cavity antenna, patent pending, has been developed by Raytheon. It exhibits low dispersion over a wide field-of-view (FOV) and multiple octaves or ultra wideband. This antenna has essentially a flat phase and amplitude response over a ±60 degree FOV. The design is scaleable over multiple frequency ranges and antennas have been built covering frequency ranges from 200 MHz

Tim Holzheimer; Garland Texas

2002-01-01

66

On the Design of Ultra Wideband FCC Compliant Integrated Radars  

Microsoft Academic Search

In this paper the design of a simple monostatic impulse radar is analyzed. The well known radar equations are revised accounting for the FCC rules. The required radar performances are quickly translated into the pulse parameters to obtain an FCC compliant radar. The effects of two major system weaknesses are also investigated: the effects of the ultra wideband channel and

Alessio Cacciatori; L. Colalongo; Z. Miklos; K. Vajna

2006-01-01

67

Optimal pilot waveform assisted modulation for ultra-wideband communications  

Microsoft Academic Search

Performance of ultra-wideband (UWB) communication systems can be enhanced by collecting multipath diversity gains, once the channels are acquired at the receiver. In this paper, we develop a novel pilot waveform assisted modulation (PWAM) scheme that is tailored for power-limited UWB communications, and can be implemented in analog form. The PWAM parameters are designed to jointly optimize performance and information

Liuqunig Yang; Georgios B. Giannakis

2002-01-01

68

Commercialization of an ultra wideband precision asset location system  

Microsoft Academic Search

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

Robert J. Fontana; Edward Richley; JoAnn Barney

2003-01-01

69

A novel ultra-wideband pulse design algorithm  

Microsoft Academic Search

We present a new algorithm to numerically generate pulses that not only have a short time duration for multiple access, but also meet the power spectral constraint of Federal Communications Commission (FCC) ultra-wideband (UWB) mask. In fact, applying our algorithm to the FCC spectral mask for UWB systems can lead to the design of multiple orthogonal pulses that are compliant.

Brent Parr; ByungLok Cho; K. Wallace; Zhi Ding

2003-01-01

70

Decision directed autocorrelation receivers for pulsed ultra-wideband systems  

Microsoft Academic Search

The need for effective capture of multipath energy presents a key challenge to receiver design for pulsed ultra- wideband (UWB) systems operating in non-line-of-sight propa- gation environments. Conventional RAKE receivers can capture only a fraction of the received signal energy under practical implementation constraints, and have to deal with stringent synchronization and channel estimation requirements. Transmit- reference and autocorrelation receivers

Shiwei Zhao; Huaping Liu; Zhi Tian

2006-01-01

71

Ultra-Wideband Multifunctional Communications\\/Radar System  

Microsoft Academic Search

We have designed, simulated, fabricated, and tested an ultra-wideband (UWB) multifunctional communication and radar system utilizing a single shared transmitting antenna aperture. Two surface acoustic wave bandpass chirp filters were used to modulate the radar and communications pulses, generating linear frequency modulation waveforms with opposite slope factors. The system operates at a center frequency of 750 MHz with 500 MHz

George N. Saddik; Rahul S. Singh; Elliott R. Brown

2007-01-01

72

Timing acquisition in ultra-wideband communication systems  

Microsoft Academic Search

The goal of this paper is to highlight the significance of the timing acquisition problem in ultra-wideband (UWB) communication systems and discuss efficient solutions to the problem. We discuss how the distinguishing features of UWB communication systems, such as their wide bandwidth and low transmission power constraints, are responsible for making the acquisition of UWB signals a difficult task. A

Sandeep R. Aedudodla; Saravanan Vijayakumaran; Tan F. Wong

2005-01-01

73

Acquisition of direct-sequence ultra-wideband signals  

Microsoft Academic Search

Very high rate packet data systems, such as those based on ultra-wideband (UWB) signaling, face an increasingly important challenge - achieving fast timing acquisition and synchronization (which must be done typically on an individual packet basis) to minimize preamble overhead and optimize (packet) throughput. Impulse based UWB modulation schemes use short (nano-second) time-duration pulses that are appropriately shaped - the

Iyappan Ramachandran; Sumit Roy

2005-01-01

74

Small Antennas for Mobile and Ultra-Wideband Communication  

Microsoft Academic Search

Mobile communication is an enormous growing market of communication and has a strong influence on the RF and microwave world. While UMTS is on the way of installation and going into business, new communication system technologies can be seen at the horizon of the communication world. One of this is UWB, the ultra wideband communication. This promising technology can become

D. Heberling; D. Manteuffel; M. Martínez-Vázquez; M. Geissler; O. Litschke

75

Ultra wideband interference effects on an amateur radio receiver  

Microsoft Academic Search

This paper illustrates the complexity of issues that arise in the accurate measurement and interpretation of ultra wideband (UWB) interference effects in narrowband receivers. The behavior of an amateur radio receiver in the presence of sinusoidal and UWB interference is studied. We characterize antenna response and receiver nonlinearities, which lead to an understanding of UWB effects on the receiver output

R. D. Wilson; R. D. Weaver; M.-H. Chung; R. A. Scholtz

2002-01-01

76

Frequency domain detectors for ultra-wideband indoor communications  

Microsoft Academic Search

In this paper we propose an innovative communication scheme for ultra-wideband systems which are based on impulse radio. The proposed system relies on both the introduction of the cyclic prefix at the transmitter and the use of a frequency domain detector at the receiver. Two different detection strategies based either on the zero forcing (ZF) or the minimum mean square

Simone Morosi; Tiziano Bianchi

2006-01-01

77

Ultra-wideband radar using Fourier synthesized waveforms  

Microsoft Academic Search

Traditional methods of ultra-wideband (UWB) radar signal generation suffer from several disadvantages such as low antenna radiation efficiency and lack of accurate control of signal parameters like pulse shape, pulse repetition interval (PRI), and its spectrum. UWB signals can be generated by expanding the desired radar waveform in a Fourier series and then synthesizing the waveform by generating the individual

Gurnam Singh Gill

1997-01-01

78

Augmented Reality Using Ultra-Wideband Radar Imagery.  

National Technical Information Service (NTIS)

The U.S. Army Research Laboratory (ARL) has been investigating the utility of ultra-wideband (UWB) synthetic aperture radar (SAR) technology for detecting concealed targets in various applications. We have designed and built a vehicle-based, low-frequency...

F. Koenig K. Sherbondy L. Nguyen

2010-01-01

79

Ultra-Wideband Tracking System Design for Relative Navigation.  

National Technical Information Service (NTIS)

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 loca...

D. Arndt J. Dusl J. D. Ni K. Dekome P. Bgo

2011-01-01

80

An Overview of the Recent Wideband Transcutaneous Wireless Communication Techniques  

PubMed Central

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

Ghovanloo, Maysam

2013-01-01

81

Effective notch Ultra-Wideband filter using ring resonator for the rejection of IEEE 802.11a  

Microsoft Academic Search

This paper proposes Ultra-Wideband (UWB) bandpass filters with dual notched band for the purpose of avoiding the interference between the UWB radio system and the existing WLAN system. The 5 GHz WLAN (Wireless Local Area Network) IEEE 802.11a exists in 5.15-5.35 GHz and 5.725-5.825 GHz which are called as lower and upper band respectively. The filter is based on ring

K. Thirumalaivasan; R. Nakkeeran; S. O. Coumar

2010-01-01

82

Non-line of Sight Error Mitigation in Ultra-wideband Ranging Systems Using Biased Kalman Filtering  

Microsoft Academic Search

In this paper, a non-line of sight (NLOS) error mitigation method based on biased Kalman filtering for ultra-wideband (UWB)\\u000a ranging is proposed. The NLOS effect on the measures of signal arrival time is considered one of the major error sources in\\u000a range estimation and time-based wireless location systems. An improved biased Kalman filtering system, incorporated with sliding-window\\u000a data smoothing and

Chin-Der Wann; Chih-Sheng Hsueh

83

Low power complementary-colpitts self-quenched super-regenerative ultra-wideband (UWB) bandpass filter in CMOS technology  

Microsoft Academic Search

This paper presents the complementary colpitts self-quenched super-regenerative ultra-wideband (UWB) bandpass filter for low power, low cost and medium data rate wireless communication systems. The high gain, large bandwidth and low power consumption are the attractive properties of self-quenched super-regenerative filters for UWB systems. The bandwidth of 1.5 GHz across the central frequency of 7.5 GHz is measured for complementary

M. Anis; R. Tielert; N. Wehn

2008-01-01

84

Atmospheric distortions of ultra-wideband pulses: method of temporal moments  

Microsoft Academic Search

Results of numerical simulation of ultra-wideband electromagnetic pulses distortions in the Earth atmosphere using the concept of temporal moments are presented. The relative broadening, the skewness, and the kurtosis of the ultra-wideband pulses as functions of a distance from source to the point of observation are computed under standard atmospheric conditions. Generalization of the form of ultra-wideband pulse radiated by

A. M. Stadnik; G. V. Ermakov

2000-01-01

85

Transform domain communication system as an ultra-wideband radar  

NASA Astrophysics Data System (ADS)

Traditionally, ultra-wideband radars increase bandwidth by using shorter pulses. However, by decreasing the pulse width, the power on target decreases and radar detection probabilities decrease. Therefore, new approaches to increase bandwidth are needed that still have adequate power on target. One radical new approach is to use a Transform Domain Communication System (TDCS) as an ultra-wideband radar. The primary advantage of this technique is that it has properties similar to Gaussian noise meaning that the radar would improve bandwidth similar to pseudo-noise (PN) sequences. Also, based on the number of carriers used to generate the TDCS code, multiple pulses can be made mutually orthogonal. This orthogonality can be exploited to effectively increase the maximum unambiguous range for pulse-Doppler radars up to the range of the horizon. In essence, TDCS radar possesses a high pulse repetition frequency (PRF) for velocity estimation and large unambiguous range.

Nunez, Abel S.; Caldwell, James T.

2005-05-01

86

Repetitive, plasma switched, gigawatt, ultra-wideband impulse transmitter development  

Microsoft Academic Search

Sandia National Laboratories has developed several repetitive, ultra-wideband (UWB), impulse transmitters to address impulse source, and to support experimental applications. The sources fall into two different classes, pulse peaking and pulse shorting. SNIPER (Sub-Nanosecond ImPulsE Radiator) is a source which uses an oil peaking switch to obtain a fast risetime (250-pS) pulse of 2-nS duration. The output voltage ranges between

R. S. Clark; L. F. Rinehart; M. T. Buttram; J. F. Aurand; J. M. Lundstrom; P. E. Patterson; L. D. Roose; W. Crowe

1992-01-01

87

A novel synchronization algorithm in ultra-wideband system  

Microsoft Academic Search

Synchronization remains one of the biggest challenges in the ultra-wideband (UWB) impulse radio system. In this paper, a frame-level synchronization algorithm is proposed in differential transmitted reference (DTR) UWB systems in the multipath environment. The signal structure is judiciously designed with the aided data and m-sequence code. Enjoying the fine property of m-sequence autocorrelation function, the proposed algorithm can suppress

Biao Liu; Tiejun Lv; Yongwei Qiao; Weidong Liu; Long Gao

2009-01-01

88

Ultra-wideband Active Receiving Array Antenna with Dual Polarization  

Microsoft Academic Search

\\u000a This chapter presents results of the investigations directed to creation of large ultra-wideband active receiving array antennas\\u000a with dual polarization. The array element is made on the basis of two crossed electric dipoles. Each arm of the dipoles is\\u000a loaded to the single-stage FET amplifier. Four such elements form a 2 × 2 module being a component of a multielement

V. I. Koshelev; E. V. Balzovsky; Yu. I. Buyanov

2010-01-01

89

Spatial group delay patterns for three ultra wideband spline antennas  

Microsoft Academic Search

The IEEE ultra wideband (UWB) standard includes both a multiple frequency carrier (MB-OFDM) and an impulse spectrum (DS-UWB) method, for which application antennas should be appropriately optimized. Small printed monopoles with outline features that can be defined by a Bezier-spline [1] have good matched impedance performance across the 3.1 - 10.6 GHz band. For communications applications, an omni-directional pattern, where

Patrick McEvoy; Matthias John; Sergio Curto; Max J Ammann

2008-01-01

90

Ultra-wideband spectral analysis using S2 technology  

Microsoft Academic Search

This paper outlines the efforts to develop an ultra-wideband spectrum analyzer that takes advantage of the broad spectral response and fine spectral resolution (?25kHz) of spatial-spectral (S2) materials. The S2 material can process the full spectrum of broadband microwave transmissions, with adjustable time apertures (down to 100?s) and fast update rates (up to 1kHz). A cryogenically cooled Tm:YAG crystal that

R. Krishna Mohan; T. Chang; M. Tian; S. Bekker; A. Olson; C. Ostrander; A. Khallaayoun; C. Dollinger; W. R. Babbitt; Z. Cole; R. R. Reibel; K. D. Merkel; Y. Sun; R. Cone; F. Schlottau; K. H. Wagner

2007-01-01

91

A novel auto-reference ultra-wideband receiver scheme  

Microsoft Academic Search

A new auto-reference (AR) transmit-receive scheme and a corresponding group decision algorithm on the generalized likelihood\\u000a ratio testing (GLRT) principle is proposed in this paper to overcome the drawbacks of the power inefficiency and the high\\u000a noise vulnerability in transmitted-reference (TR) ultra-wideband (UWB) systems. A partly overlapped detection window structure\\u000a is introduced in which the decided data frames are regarded

Xuewen Liao; Shihua Zhu; Erlin Zeng

2007-01-01

92

Human detection and tracking via Ultra-Wideband (UWB) radar  

Microsoft Academic Search

This paper presents an algorithm for human presence detection and tracking using an Ultra-Wideband (UWB) impulse-based mono-static radar. UWB radar can complement other human tracking technologies, as it works well in poor visibility conditions. UWB electromagnetic wave scattering from moving humans forms a complex returned signal structure which can be approximated to a specular multi-path scattering model (SMPM). The key

SangHyun Chang; Michael T. Wolf; Joel W. Burdick

2010-01-01

93

Silicon-Based Ultra-Wideband BeamForming  

Microsoft Academic Search

Ultra-wideband (UWB) beam-forming, a special class of multiple-antenna systems, allows for high azimuth and depth resolutions in ranging and imaging applications. This paper reports a fully integrated UWB beam-former featuring controllable true time delay and power gain. Several system and circuit level parameters and characterization methods influencing the design and testing of UWB beam-formers are discussed. A UWB beam-former prototype

Jonathan Roderick; Harish Krishnaswamy; Kenneth Newton; Hossein Hashemi

2006-01-01

94

Low power 8GHz ultra-wideband active balun  

Microsoft Academic Search

A new low-power CMOS active balun is designed for ultra-wideband applications, using a pair of common-source NMOS and common-gate PMOS transistors. This balun gives an impedance transformation ratio of 1:2. Without compensation feedback, the circuit provides a differential signal within 2dB and 3deg of gain and phase imbalance, respectively, up to 8-GHz. Total power consumption is only 1.44 mW at

Ta-Tao Hsu; Chien-Nan Kuo

2006-01-01

95

Planar elliptical element ultra-wideband dipole antennas  

Microsoft Academic Search

Abstract: This note introduces a new class of ,planar ultra-wideband (UWB) dipoles that use elliptical elements. These ,antennas offer good ,dipole performance ,over nearly two octaves in frequency. Unlike ,more traditional broadband dipole elements that must be around a quarter-wavelength to radiate efficiently, planar elliptical UWB dipoles still exhibit a –10 dB return loss for a 0.20? element size, and

H. G. Schantz

2002-01-01

96

Daredevil: ultra-wideband radar sensing for small UGVs  

Microsoft Academic Search

We are developing an ultra wideband (UWB) radar sensor payload for the man-portable iRobot PackBot UGV. Our goal is to develop a sensor array that will allow the PackBot to navigate autonomously through foliage (such as tall grass) while avoiding obstacles and building a map of the terrain. We plan to use UWB radars in conjunction with other sensors such

Brian Yamauchi

2007-01-01

97

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

98

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

99

The Interval Modulation System For The Ultra-Wideband Vehicular Radar  

Microsoft Academic Search

Since the (FCC) Federal Communications Commission approved the (UWB) Ultra-wideband application into the civilian areas, research on the UWB vehicular radar aroused much interest. Using of vehicular sensing radar is an important method in preventing the occurrence of traffic accidents, and enhance the radar's performance can directly improve the effectiveness of the collision prevention system. Ultra-wideband is a relatively new

Xi Li; Zhiguo Wang; Yuanchun Fei; Dechun Guo

2006-01-01

100

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

101

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

102

Analysis of Ultra-wideband Impulse Radio Over Multimode Fiber Ranging System  

NASA Astrophysics Data System (ADS)

Ultra-wideband impulse radio (UWB-IR)-based systems are well known for their inherent capability to provide accurate ranging [1-3]. Remote positioning of such systems using Radio over MultiMode Fiber (RoMMF) technology is advantageous, for it provides a cost-effective way of system deployment by the consolidation of head-end equipment. In this chapter, we describe the details of a system model for evaluating the performance of a ranging system employing UWB-IR over multimode fiber. As the system uses low data rate digital communication to obtain range information, its quality can be studied using Bit Error Ratio (BER). This model combines wireless and radio over fiber sections of the system to predict system performance in terms of BER.

George, J.; Thelen, D.; Chamarti, A.; Ng'oma, A.; Sauer, M.

103

Ultra-wideband direction finding using fiber optic transversal filters  

NASA Astrophysics Data System (ADS)

This report describes a wideband electro-optic direction finding (DF) processor using an array of laser diodes, an array of photodetectors, and a network of fiber optic delay lines. This DF filter offers a potential operational bandwidth in excess of 10 GHz and allows for multiple, simultaneous beam angular responses with peaks that are independent of frequency. Two eight-laser, two-transversal filter laboratory test model DF devices, one using multimode optical fiber and the other single-mode fiber, were constructed. These experimental matched-delay filters are operable in the 200- to 1800- systems' sensitivity, dynamic range, angular resolution, and frequency response. It is concluded from theoretical and experimental results obtained in this investigation that the multitude DF device is slightly superior in performance to the single-mode system due to the higher throughput optical power levels possible with multimode systems. Further, it is concluded that the fiber optics matched-delay filter can be a useful device for ultra-wideband direction finding.

Pappert, S. A.

1987-03-01

104

Ultra-wideband millimetre-wave self-oscillating mixer  

NASA Astrophysics Data System (ADS)

The performance of an ultra-wideband millimeter-wave GaAs self-oscillating harmonic mixer (SOHM) is presented. Conversion gain, minimum detectable signal (MDS) and 'self-pumping' power level have been measured for the 30 GHz frequency coverage centred at approximately 85 GHz. Sensitivity better than - 71 dBm (without automatic frequency control) using 33 MHz bandwidth, and conversion gain as high as 12 dB have been achieved. For input mm-wave dynamic range of 55 dB (from -20 dBm to -75 dBm), a useful down conversion gain-compression has led to a corresponding variation of only 0.5 mV in the peak-to-peak 70 MHz IF signal (from 0.94 kmV to 0.44 mV).

Lazarus, M. J.; Pantoja, F. R.

1983-08-01

105

Ultra-wideband noise radar based on optical waveform generation  

NASA Astrophysics Data System (ADS)

A microwave-photonic, ultra-wideband (UWB) noise radar system is proposed and demonstrated. The system brings together photonic generation of UWB waveforms and fiber-optic distribution. The use of UWB noise provides high ranging resolution and better immunity to interception and jamming. Distribution over fibers allows for the separation the radar-operating personnel and equipment from the location of the front-end. The noise waveforms are generated using the amplified spontaneous emission that is associated with stimulated Brillouin scattering in a standard optical fiber, or with an erbium-doped fiber amplifier. Our experiments demonstrate a proof of concept for an integrated radar system, driven by optically generated UWB noise waveforms of more than 1 GHz bandwidth that are distributed over 10 km distance. The detection of concealed metallic object and the resolving of two targets with the anticipated ranging resolution are reported.

Grodensky, Daniel; Kravitz, Daniel; Zadok, Avi

2012-05-01

106

Performance analysis of ultra-wideband antennas for microradar applications  

NASA Astrophysics Data System (ADS)

This paper presents three different types of ultra-wideband (UWB) antennas for RF micro-radar applications in range of 1-3 GHz and discusses performance characteristics of each antenna. The electromagnetic radiation properties of antennas are analyzed based on their gain, bandwidth, voltage standing wave ratio (VSWR), conductivity, and form and size factors. In addition, the performance of each antenna is investigated with different feed line configuration to determine influence of feed line configuration upon the performance of each UWB antenna. The antennas were modeled using electromagnetic simulation software, FEKO. The software simulates the performance of each antenna via Method of Moment (MoM) technique that is a powerful method for analysis of electromagnetic radiation characteristics of RF antennas. This paper presents the simulation-based performance comparison of the three selected UWB antennas under the same operational bandwidth.

Sarfaraz, Maysam; Shirkhodaie, Amir; Mitra, Atindra

2009-05-01

107

Daredevil: ultra-wideband radar sensing for small UGVs  

NASA Astrophysics Data System (ADS)

We are developing an ultra wideband (UWB) radar sensor payload for the man-portable iRobot PackBot UGV. Our goal is to develop a sensor array that will allow the PackBot to navigate autonomously through foliage (such as tall grass) while avoiding obstacles and building a map of the terrain. We plan to use UWB radars in conjunction with other sensors such as LIDAR and vision. We propose an algorithm for using polarimetric (dual-polarization) radar arrays to classify radar returns as either vertically-aligned foliage or solid objects based on their differential reflectivity, a function of their aspect ratio. We have conducted preliminary experiments to measure the ability of UWB radars to detect solid objects through foliage. Our initial results indicate that UWB radars are very effective at penetrating sparse foliage, but less effective at penetrating dense foliage.

Yamauchi, Brian

2007-05-01

108

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

109

Ultra-wideband radar methods and techniques of medical sensing and imaging  

NASA Astrophysics Data System (ADS)

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, Christine N.; Chang, John T.; Romero, Carlos E.; Watson, Joseph; Pearce, Fred J.; Levin, Nathan

2005-11-01

110

SEMICONDUCTOR INTEGRATED CIRCUITS: A 6-9 GHz ultra-wideband CMOS PA for China's ultra-wideband standard  

NASA Astrophysics Data System (ADS)

A 6-9 GHz ultra-wideband CMOS power amplifier (PA) for the high frequency band of China's UWB standard is proposed. Compared with the conventional band-pass filter wideband input matching methodology, the number of inductors is saved by the resistive feedback complementary amplifying topology presented. The output impendence matching network utilized is very simple but efficient at the cost of only one inductor. The measured S22 far exceeds that of similar work. The PA is designed and fabricated with TSMC 0.18 ?m 1P6M RF CMOS technology. The implemented PA achieves a power gain of 10 dB with a ripple of 0.6 dB, and S11 < -10 dB over 6-9 GHz, S22 < -35 dB over 4-10 GHz. The measured output power at the 1 dB compression point is over 3.5 dBm from 6 to 9 GHz. The PA dissipates a total power of 21 mW from a 1.8 V power supply. The chip size is 1.1 × 0.8 mm2.

Zhendong, Gao; Zhiqiang, Li; Haiying, Zhang

2010-09-01

111

System Analysis of Ultra-Wideband Instrumentation Radars: Impulse vs. Stepped-Chirp Approaches.  

National Technical Information Service (NTIS)

As part of an ongoing effort to determine the utility of ultra-wideband (UWB) radar systems for military application, an experimental program was developed and executed to collect terrain clutter data using high resolution waveforms in the ultra high freq...

J. Ralston

1993-01-01

112

Ultra-wideband signal propagation experiments in liquid media  

NASA Astrophysics Data System (ADS)

Ultra-wideband (UWB) signals exhibit different characteristics upon propagation through matter compared with narrowband signals. The latter keeping a sinusoidal shape during different forms of signal propagation. The behavior of narrowband signals does not apply to UWB signals in many cases. Presently, the possibilities for development of UWB signaling technology remain largely unexplored. Only a few applications have been developed due to strict regulations by the Federal Communications Commission (FCC). In this paper we describe a series of experiments that have been carried out to determine the behavior of UWB signals and their properties. A TEM horn antenna has been made for radiating UWB signals. Experiments on pulse propagation have been carried out including an application to detection of stationary metal objects. A high accuracy in detecting metal objects has been achieved. A procedure for propagating UWB signals through a liquid medium of given salt concentration has been demonstrated, providing a basis for studying UWB signal propagation in biological matter. A new pulsewidth definition was adopted which is suitable for UWB signal propagation.

Challa, Shravan; Mitra, Atindra; Selmic, Rastko; Simicevic, Neven

2008-05-01

113

Design of 3.1–10.6 GHz ultra-wideband CMOS low noise amplifier with current reuse technique  

Microsoft Academic Search

A new low complexity ultra-wideband 3.1–10.6GHz low noise amplifier (LNA), designed in a chartered 0.18?m RFCMOS technology, is presented in this paper. The ultra-wideband LNA only consists of two simple amplifiers with an inter-stage inductor connected. The first stage utilizing a resistive current reuse and dual inductive degeneration techniques is used to attain a wideband input matching and low noise

Qiuzhen Wan; Chunhua Wang

2011-01-01

114

Ultra-Wideband Tapered Slot Antenna Arrays with Parallel-Plate Waveguides  

NASA Astrophysics Data System (ADS)

Owing to their ultra-wideband characteristics, tapered slot antennas (TSAs) are used as element antennas in wideband phased arrays. However, when the size of a TSA is reduced in order to prevent the generation of a grating lobe during wide-angle beam scanning, the original ultra-wideband characteristics are degraded because of increased reflections from the ends of the tapered slot aperture. To overcome this difficulty, we propose a new antenna structure in which parallel-plate waveguides are added to the TSA. The advantage of this new structure is that the reflection characteristics of individual antenna elements are not degraded even if the width of the antenna aperture is very small, i.e., approximately one-half the wavelength of the highest operating frequency. In this study, we propose a procedure for designing the new antenna through numerical simulations by using the FDTD method. In addition, we verify the performance of the antenna array by experiments.

Yamaguchi, Satoshi; Miyashita, Hiroaki; Takahashi, Toru; Otsuka, Masataka; Konishi, Yoshihiko

115

An overview of Sandia National Laboratories' plasma switched, gigawatt, ultra-wideband impulse transmitter program  

Microsoft Academic Search

Sandia National Laboratories has developed several repetitive, ultra-wideband (UWB), impulse transmitters to address impulse source technology and to support experimental applications. The sources fall into two different classes, pulse peaking and pulse shorting depending on how the UWB frequency components are generated. The frequency spectrum of the radiated pulse from these sources include the spectrum of 100-MHz to 3-GHz. Depending

R. S. Clark; L. F. Rinehart; M. T. Buttram; J. F. Aurand

1992-01-01

116

Timing synchronization for ultra-wideband (UWB) multi-band OFDM systems  

Microsoft Academic Search

An algorithm based on distinguishing the first significant multipath (FTA) is proposed to address the critical issue of symbol timing synchronization in Ultra wideband (UWB) Multi-band OFDM (MB-OFDM) systems. The algorithm attempts to locate the frame synchronization sequence and pinpoint the exact start of the Fast Fourier Transform (FFT) window by first accumulating multipath energies and then discerning for first

Chin Wee Yak; Zhongding Lei; S. Chattong; Thiang Tjeng Tjhung

2005-01-01

117

Timing synchronization and frequency offset estimation for Ultra-Wideband (UWB) MultiBand OFDM systems  

Microsoft Academic Search

An algorithm based on distinguishing the first significant multipath (FTA) is proposed to address the critical issue of symbol timing synchronization and carrier frequency offset estimation in ultra wideband (UWB) multi-band OFDM (MB-OFDM) systems. FTA pinpoints the frame synchronization sequence and the start of its fast Fourier transform (FFT) window by accumulating multipath energies and then discerning for first significant

Chin Wee Yak; Zhongding Lei; S. Chattong; Tjeng Thiang Tjhung

2005-01-01

118

An Ultra-Wideband Bidirectional Antenna with Modified Circular Disc Monopole Excited Elliptical Ring  

Microsoft Academic Search

The antenna design for ultra-wideband (UWB) signal radiation is one of the main challenges of the UWB system, especially when the antenna can satisfy the requirement of low-cost, compactness, linear polarization and bidirectional pattern. This paper proposes a UWB bidirectional antenna with introducing the psi shape feeder to circular disc monopole (CDM) excited elliptical ring for modern base station in

Krittaya Chawanonphithakl; Chuwong Phongcharoenpanich; Sompol Kosulvit; Monai Krairiksh

2007-01-01

119

Feasibility of ultra-wideband SAW RFID tags meeting FCC rules  

Microsoft Academic Search

We discuss the feasibility of surface acoustic wave (SAW) radio-frequency identification (RFID) tags that rely on ultra-wideband (UWB) technology. We propose a design of a UWB SAW tag, carry out numerical experiments on the device performance, and study signal processing in the system. We also present experimental results for the proposed device and estimate the potentially achievable reading distance. UWB

S. Harma; V. P. Plessky; Xianyi Li; P. Hartogh

2009-01-01

120

Ultra-wideband radio-over-optical fiber: Technologies and applications  

Microsoft Academic Search

This paper investigates the concepts, technologies and applications of ultra-wideband radio over optical fiber (UROOF) and provides overview of key results obtained through EC funded project UROOF. We study the theoretical aspects of the UROOF channel, and demonstrate experimentally, key features of this new technology, through a validation platform. UROOF envision that within 3-5 years, fiber optics will be widely

Moshe Ran; Yossef Ben-Ezra; Boris Lembrikov

2008-01-01

121

Practical search strategy for ultra wideband signal acquisition in the dense multipath channel  

Microsoft Academic Search

In a previous work the authors proposed a search strategy based on the golden section for coarse acquisition of ultra wideband (UWB) signals in the dense multipath channel. The proposed method achieved practically the minimum mean acquisition time under a simplistic model. In this paper those results are extended by showing that the golden section strategy is especially advantageous when

Eva Arias-de-Reyna; J. I. Acha-Catalina

2006-01-01

122

Ultra-wideband radar sensors for short-range vehicular applications  

Microsoft Academic Search

The recent approval granted by the Federal Communications Commission (FCC) for the use of ultra-wideband signals for vehicular radar applications has provided a gateway for the introduction of these sensors in the commercial arena as early as 2004. However, the rules governing the allowable spectral occupancy create significant constraints on the sensors' operation. This is further complicated by the variety

Ian Gresham; Alan Jenkins; Robert Egri; Channabasappa Eswarappa; Noyan Kinayman; Nitin Jain; Richard Anderson; Frank Kolak; Ratana Wohlert; Shawn P. Bawell; Jacqueline Bennett; Jean-Pierre Lanteri

2004-01-01

123

Development of band pass filter for ultra wideband (UWB) communication systems  

Microsoft Academic Search

This paper presents a band pass filter for ultra wideband (UWB) communication systems. The Federal Communication Commission (FCC) authorized the commercial use of the UWB technology in February 2002. Where, the frequency range of the spectrum mask in an indoor environment is from 3.1 GHz to 10.6 GHz. To transmit digital information on the maximum of 1 Gbps using this

A. Saito; H. Harada; A. Nishikata

2003-01-01

124

Antenna-source integrated ultra-wideband electromagnetic pulses radiating device  

Microsoft Academic Search

In 1901 Marconi tested the propagation property of electromagnetic fields using the folded monopole antenna, which was 150 ft in height, 200 ft in width, and excited at the tip of the monopole by the shorting of a spark gap. In the study of ultra-wideband electromagnetic pulse technology, we noted that with some improvements, the prototype method Marconi used has

Xiaoxin Song; Guozhi Liu; Yajun Fan; Xiaolong Liu; Feng Liu

1998-01-01

125

Comparison between two simulation techniques and measurement results for ultra wideband indoor radio channels  

Microsoft Academic Search

Two three-dimensional simulation techniques (Polyhedral Beam Tracing and Finite Difference Time Domain) for modeling an ultra wideband (850 MHz) indoor radio channel are compared among themselves and with experimental data. Measurements were performed within a typical hall (indoor) scenario at Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) to extract channel parameters such as the power delay profiles. I. INTRODUCTION

F. J. B. Barros; L. A. R. Ramirez; E. Costa; F. J. V. Hasselmann; G. L. Siqueira

2011-01-01

126

Ultra-wideband two-cluster tracking system design with angle of arrival algorithm  

Microsoft Academic Search

This paper describes a design 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 during early exploration missions when satellite navigation systems are not available. The UWB technology is exploited to implement the tracking system due to its

J. Ni; D. Arndt; P. Ngo; C. Phan; J. Gross

2006-01-01

127

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

128

Design of CMOS based ultra wideband low noise amplifier using active shunt feedback technique  

Microsoft Academic Search

This paper presents design technique of CMOS based UWB low noise amplifier using active shunt feedback technique at 0.18µm technology. The proposed low noise amplifier is able to provide high gain with flatness at ultra wideband (UWB) range, which yet consumes small power with simple and compact design model. This LNA is implemented using Cascode amplifier topology with active shunt

Ashish Bharade; Hemant Ghyvat; D. S. Ajnar; Pramod Jain

2011-01-01

129

Performance Analysis of Channel Shortening of RAKE Receiver in Ultra-Wideband Systems  

Microsoft Academic Search

In this paper, the performance of RAKE receiver on channel shortening in ultra-wideband (UWB) systems is studied by analyzing the impact of inter-symbol interference (ISI) on the bit error rate (BER) error floor in dense multipath channel environments. A closed form expression for BER with Nakagami channel model is developed. The equivalent channel length after RAKE receiver is derived by

Liang Zhang; Chenyang Yang

2006-01-01

130

Performance of an ultra wideband radar for detection of water accumulation in the human bladder  

Microsoft Academic Search

This paper presents an Impulse Radio Ultra Wideband (IR-UWB) radar for detecting water accumulation in the human bladder. The goal is to monitor the level of urine in patients who suffer from urinary incontinence. This is achieved by detecting the reflected UWB signals from the boundaries of human tissues such as muscle and urine. The reflection properties are investigated both

Xuyang Li; Elena Pancera; Lukasz Niestoruk; Wilhelm Stork; Thomas Zwick

2010-01-01

131

Design of Ultra-Wideband Substrate Integrated Waveguide (SIW) Filters in Zigzag Topology  

Microsoft Academic Search

In this letter we propose a modified substrate integrated waveguide (SIW) zigzag filter topology, which allows the flexible introduction of extra cross-couplings between non adjacent resonators. This novel topology permits to control the location of the transmission zeros, thus improving the resulting filter selectivity. Therefore, it has been used to design filters in compliance with the restrictive ultra-wideband European mask.

FermÍn Mira; Jordi Mateu; Santiago Cogollos; Vicente E. Boria

2009-01-01

132

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

133

Frequency domain detection for ultra-wideband communications in the indoor environment  

Microsoft Academic Search

We propose an innovative communication scheme for ultra-wideband systems which are based on impulse radio technologies. The proposed system relies on both the introduction of the cyclic prefix at the transmitter and the use of a frequency domain detector at the receiver. In particular, two different detection strategies based either on the zero forcing (ZF) or the minimum mean square

Tiziano Bianchi; Simone Morosi

2004-01-01

134

Improved Design Guidelines for the Ultra Wideband Monopole-Dielectric Resonator Antenna  

Microsoft Academic Search

This letter examines in detail multiple resonance phenomenon responsible for the ultra wideband response of the hybrid monopole-dielectric resonator antenna (DRA). The physical insight gained by this investigation has lead to improved guidelines for designing the antennas for any specified frequency band. These simple guidelines are then verified using both simulated and measured data

Debatosh Guha; Yahia M. M. Antar; Apisak Ittipiboon; Aldo Petosa; David Lee

2006-01-01

135

Ultra-wideband antennas for combined magnetic resonance imaging and UWB radar applications  

Microsoft Academic Search

Magnetic resonance imaging (MRI) is one of the most highly appreciated medical diagnostic techniques worldwide. Recent developments aim at adding the capability of creating focused images of moving objects. Among the potential navigator techniques required for such an improved MRI is ultra-wideband (UWB) radar. We have studied the performance of UWB antennas for biomedical imaging inside the 3-Tesla MRI system

U. Schwarz; F. Thiel; F. Seifert; R. Stephan; M. Hein

2009-01-01

136

Low-frequency ultra-wideband synthetic aperture radar 1995 BoomSAR tests  

Microsoft Academic Search

The Army Research Laboratory has been investigating the potential of ultra-wideband synthetic aperture radar (UWB SAR) technology to detect and classify targets embedded in foliage or in the ground. The UWB foliage penetration (FOPEN) radar program has been extended to include the evaluation of ground penetration (GPEN) radar technology. ARL is investigating these problems by collecting high quality, precision data

Lynn Happ; Karl A. Kappra; Marc A. Ressler; Jeffrey P. Sichina; Keith Sturgess; Francis Le

1996-01-01

137

On the coexistence of ultra-wideband and narrowband radio systems  

Microsoft Academic Search

Ultra-wideband (UWB) signals will encounter many interference sources, primarily from relatively narrowband (NB) systems. In addition., UWB signals will also affect a large number of NB radios; of critical importance is the potential interference with GPS, E-911, and navigation bands, as well as cellular bands. There is a rich and growing literature on UWB radios; however, issues related to interference

Ananthram Swami; Brian Sadler; Joi Turner

2001-01-01

138

Wideband antenna and wideband bandpass filter for wearable systems  

Microsoft Academic Search

With the rapid development in wearable systems in recent years, the need for wireless communication components integrated into clothing is increasing. Wearable antennas and radio frequency (RF) devices are faced with a considerable design challenge, especially in the gains of antennas and performances of filters. This paper presents a wearable antenna and a wearable bandpass filter for ultra-wideband (UWB) communication

Shanshan Gao; Shaoqiu Xiao; Bing-Zhong Wang; Xinhe Xu

2010-01-01

139

Ultra-Wideband Direction Finding Using Fiber Optic Transversal Filters.  

National Technical Information Service (NTIS)

This report describes a wideband electro-optic direction finding (DF) processor using an array of laser diodes, an array of photodetectors, and a network of fiber optic delay lines. This DF filter offers a potential operational bandwidth in excess of 10 G...

S. A. Pappert

1987-01-01

140

An Open Access Wideband Multi-Antenna Wireless Testbed with Remote Control Capability  

Microsoft Academic Search

This paper introduces an open access wideband multi- antenna wireless testbed. The testbed is configured as a four transmit antenna by four receive antenna system based on software defined radio techonology. It operates in the 2.4GHz ISM band and supports an RF bandwidth compati- ble to IEEE 802.11a\\/g standard. A robotic positioning sys- tem has been developed to automatically control

Weijun Zhu; David W. Browne; Michael P. Fitz

2005-01-01

141

Ultra Wideband (UWB) communication vulnerability for security applications  

Microsoft Academic Search

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

Cooley; H. Timothy

2010-01-01

142

Ultra-Wideband Ultra-Low-DC-Power High Gain Differential-Input Low Noise Amplifier MMIC Using InAs\\/AlSb HEMT  

Microsoft Academic Search

This paper reports an ultra-wideband ultra-low-DC power high gain MMIC low noise amplifier (LNA) with differential RF input using 0.1-mum gate length InAs\\/AlSb metamorphic HEMTs, fabricated and characterized on a GaAs substrate. For testing purpose and for generating a differential RF input, a 3-12 GHz wideband on-chip MMIC balun is connected to the differential input. Even with the loss of

Bob Y. Ma; Joshua Bergman; Peter S. Chen; Jonathan B. Hacker; Gerard Sullivan; Bobby Brar

2007-01-01

143

Ultra-Wideband Transmission Over Low Loss PCF  

Microsoft Academic Search

The explosive growth in Internet traffic will lead to a demand for greater capacity. Wavelength-division-multiplexing (WDM) transmission using a broad wavelength region is considered a promising candidate transmission technology with which to meet this demand. Photonic crystal fibers (PCF) are attractive in terms of realizing wideband WDM transmission because they have unique features that are unavailable with conventional single-mode fibers,

Kenji Kurokawa; Kazuhide Nakajima; Kyozo Tsujikawa; Takashi Yamamoto; Katsusuke Tajima

2009-01-01

144

An ultra-wideband microwave tomography system: Preliminary results  

Microsoft Academic Search

We describe a 2D wide-band multi-frequency microwave imaging system intended for biomedical imaging. The system is capable of collecting data from 2-10 GHz, with 24 antenna elements connected to a vector network analyzer via a 2 times 24 port matrix switch. Through the use of two different nonlinear reconstruction schemes: the Multiplicative-Regularized Contrast Source Inversion method and an enhanced version

Colin Gilmore; Puyan Mojabi; Amer Zakaria; Majid Ostadrahimi; Cam Kaye; Sima Noghanian; Lotfollah Shafai; Stephen Pistorius; Joe LoVetri

2009-01-01

145

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

146

A novel orthogonal linearly polarized directional antenna for ultra wideband applications  

Microsoft Academic Search

In this paper, a novel ultra wideband (UWB) Vee dipole antenna with dual linear orthogonal polarization is introduced. The antenna consists of a 4-arm Vee dipole antenna with a novel arm shape fed by two coaxial cables with UWB baluns. The antenna occupies a volume of (0.44 ?L × 0.44 ?L × 0.44 ?L) without the coaxial balun. The boresight

Abdelhalim Mohamed; Lotfollah Shafai

2010-01-01

147

An ultra-wideband transmitter based on a new pulse generator  

Microsoft Academic Search

The paper describes an ultra-wideband transmitter, which incorporates an innovative carrier-based pseudo-Gaussian pulse generator satisfying FCC rules with no-filter and high spectral efficiency. The design includes a BPSK modulator, a ramp generator and an output buffer. The transmitter is designed for run up to 500 Mpps in the UWB 3-5-GHz band and it is implemented in 0.28-mum CMOS technology with

Marco Cavallaro; Egidio Ragonese; Giuseppe Palmisano

2008-01-01

148

Ultra-wideband omnidirectional conformable low-profile mode-0 spiral-mode microstrip (SMM) antenna  

Microsoft Academic Search

An ultra-wideband low-profile platform-conformable omnidirectional antenna based on the mode-0 SMM antenna has been developed. Its 10:1 gain bandwidth is slightly larger than that of the well-established conical monopole, yet its height is less than half that of the monopole. Compared with other well-known low-profile omnidirectional antennas with a gain bandwidth over 2:1, its gain bandwidth of 10:1 is much

Johnson J. H. Wang; Chris J. Stevens; D. J. Triplett

2005-01-01

149

A Power-Efficient Ultra-Wideband Pulse Generator Based on Multiple PM-IM Conversions  

Microsoft Academic Search

A novel photonic generation of power-efficient ultra-wideband (UWB) pulse by incoherent summation of two asymmetric monocycle pulses with inverted polarities is experimentally demonstrated. The principles of multiple cross-phase modulations in a highly nonlinear fiber and multiple phase modulation to intensity modulation conversions in a commercially available arrayed-waveguide grating are used. The combined UWB pulse exploiting spectral efficiency of 50.59% in

Enbo Zhou; Xing Xu; King-Shan Lui; Kenneth Kin-Yip Wong

2010-01-01

150

An ultra-wideband vertical transition from microstrip to stripline in PCB technology  

Microsoft Academic Search

An ultra-wideband transition from microstrip to stripline in PCB technology is presented applying only through via holes for simple fabrication. The design is optimized using full-wave EM simulations. A prototype is manufactured and measured achieving a return loss better than 8.7dB and an insertion loss better than 1.2 dB in the FCC frequency range. A meander-shaped delay line in stripline

Mario Leib; Michael Mirbach; Wolfgang Menzel

2010-01-01

151

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

152

Orthogonally-spread block transmissions for ultra-wideband impulse radios  

Microsoft Academic Search

Differential, transmitted reference (TR) and energy detection (ED) based ultra-wideband impulse radios (UWB- IR) can collect the rich multipath energy offered by UWB channels with a low-complexity receiver. However, they perform satisfactorily only when the channel induced inter-pulse inter- ference (IPI) is negligible. This can be achieved by appending a guard interval with duration greater than or equal to the

Shahrokh Farahmand; Xiliang Luo; Georgios B. Giannakis

2008-01-01

153

A 4?7GHz ultra wideband VCO with tunable active inductor  

Microsoft Academic Search

An ultra-wideband CMOS VCO with tuning range of 3.8~7.4 GHz is presented, using tunable active inductor (TAI). The inductance of TAI can be tuned from 0.34~0.61 nH by active tunable resistor, and exhibits a quality factor of about 90. The VCO is designed in a 0.18 um CMOS technology with power dissipation of around 29.1 mW and phase noise (PN)

M. Mehrabian; A. Nabavi; N. Rashidi

2008-01-01

154

pHEMT and mHEMT Ultra Wideband Millimeterwave Balanced Resistive Mixers  

Microsoft Academic Search

Two ultra wideband millimeterwave single balanced resistive mixers utilizing a Marchand balun for the LO-hybrid are simulated, fabricated and characterized for 30-60 GHz in both up and down conversion. Two different versions of the mixer were manufactured in a commercial pHEMT-MMIC and a mHEMT-MMIC process respectively. A measured down conversion loss of approximately 6 to 12 dB over the whole

Sten Gunnarsson; Klas Yhland; Herbert Zirath; Ericsson AB

2003-01-01

155

Ultra wideband signal impact on IEEE802.11b 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

Matti Hämäläinen; Jani Saloranta; Juha-Pekka Mäkelä; Ian Oppermann; Tero Patana

2003-01-01

156

Low Power Digital Baseband for Impulse Radio Ultra-Wideband Transceiver  

Microsoft Academic Search

In this paper, a low power digital baseband to be used together with impulse-radio ultra wideband radio frequency front-end\\u000a has been presented. It can provide received pulse synchronization required for burst mode and low power operation. It also\\u000a overcomes clock drift issue between different transceivers. The clock and data recovery is implemented fully in digital domain\\u000a without the need of

Wei Da Toh; Yuanjin Zheng; Chun-Huat Heng

157

System-on-package ultra-wideband transmitter using CMOS impulse generator  

Microsoft Academic Search

In this paper, a low-cost CMOS ultra-wideband (UWB) impulse transmitter module with a compact form factor is proposed for impulse-radio communications. The module consists of a CMOS impulse generator, a compact bandpass filter (BPF), and a printed planar UWB antenna. The impulse generator is designed using a Samsung 0.35-?m CMOS process for low-cost and low-power fabrication. The measurement shows the

Junwoo Lee; Young-Jin Park; Myunghoi Kim; Changwook Yoon; Joungho Kim; Kwan-Ho Kim

2006-01-01

158

MEMS-integrated ultra-wideband terahertz traveling wave tube amplifier  

Microsoft Academic Search

An ultra-wideband TWT amplifier is being developed for THz communication, sensing, and imaging applications. Using FDTD-PIC simulation, we demonstrated that, for an electron beam power of 5 kW, a staggered double grating array produces 150 to 275 W, corresponding to 3 - 5.5% efficiency, at 0.22 THz over ~ 30% bandwidth with greater than 12 dB\\/cm growth rate. The Ka-band

Young-Min Shin; Jinfeng Zhao; Larry R. Barnett; Neville C. Luhmann Jr

2009-01-01

159

A Two-Step Time of Arrival Estimation Algorithm for Impulse Radio Ultra Wideband Systems  

Microsoft Academic Search

High time resolution of ultra wideband (UWB) signals facilitates very precise positioning capa- bilities based on time-of-arrival (TOA) measurements. Although the theoretical lower bound for TOA estimation can be achieved by the maximum likelihood principle, it is impractical due to the need for extremely high-rate sampling and large number of multipath components. On the other hand, the conventional correlation-based algorithm,

Sinan Gezici; Zafer Sahinoglu; Andreas F. Molisch; Hisashi Kobayashi; H. Vincent Poor

2005-01-01

160

A 30 GHz Variable Gain Amplifier With High Output Voltage Swing for Ultra-Wideband Radar  

Microsoft Academic Search

This paper reports on the analysis, design and characterization of a 30 GHz fully differential variable gain amplifier for ultra-wideband radar systems. The circuit consists of a variable gain differential stage, which is fed by two cascaded emitter followers. Capacitive degeneration and inductive peaking are used to enhance bandwidth. The maximum differential gain is 11.5 dB with plusmn1.5 dB gain

Benjamin Sewiolo; Georg Fischer; Robert Weigel

2009-01-01

161

Dual Time-Interleaved Successive Approximation Register ADCs for an Ultra-Wideband Receiver  

Microsoft Academic Search

Ultra-wideband radio requires Nyquist sampling rates of at least 500 MS\\/s with low resolutions. While flash is the traditional choice for these specifications, a comparative energy model is used to show the potential energy savings of the time-interleaved successive approximation register architecture, which requires only a linear number of comparisons versus exponential for flash. A dual 500-MS\\/s, 5-bit ADC chip

Brian P. Ginsburg; Anantha P. Chandrakasan

2007-01-01

162

Ultra-wideband duplexers for low and high peak power applications  

Microsoft Academic Search

Two different duplexers have been conceived, designed and tested that allow for using an impulse ultra-wideband (UWB) radar in a monostatic configuration. The first one, which is based on a fast GaAs SPDT switch, is usable with a low peak power transmitter (<100 mW), while the second one, completely passive, is intended for high peak power applications (up to 50

M. Piette

1998-01-01

163

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

164

An Ultra-Wideband Impulse-Radio Communication Method and Transceiver  

Microsoft Academic Search

The present paper describes the physical layer of an ultra-wideband impulse radio (UWB-IR) communication system, together with its implementation in a fully integrated transceiver. The objective of this work was to design and test a low-power radio communication system for medium data-rate, short-range communication. The system is based on frequency hopping on-off keying modulation (FH-OOK) for transmission, combined with a

Emil Novakov; Jean-Michel Fournier

2009-01-01

165

pHEMT and mHEMT ultra wideband millimeterwave balanced resistive mixers  

Microsoft Academic Search

Two ultra wideband millimeterwave single balanced resistive mixers utilizing a Marchand balun for the LO-hybrid are simulated, fabricated and characterized for 30-60 GHz in both up and down conversion. Two different versions of the mixer were manufactured in a commercial pHEMT-MMIC and a mHEMT-MMIC process respectively. A measured down conversion loss of approximately 6 to 12 dB over the whole

S. Gunnarsson; Klas Yhland; H. Zirath

2004-01-01

166

Permittivity-matched compact ceramic ultra-wideband horn antennas for biomedical diagnostics  

Microsoft Academic Search

Ultra-wideband (UWB) biomedical radar systems are an important means for the diagnostic inspection and monitoring of physiological signatures. Geometrically small antennas and high-resolution imaging techniques are required for such appli- cations. We have analysed the time-domain reflection and trans- mission characteristics of compact ceramic double-ridged horn antennas, developed for contact-mode measurements with a permittivity matched to human tissues. Preliminary volunteer

F. Scotto di Clemente; M. Helbig; J. Sachs; U. Schwarz; R. Stephan; M. A. Hein

2011-01-01

167

A Novel Modulation Waveform on Ultra-Wideband Based Cognitive Radio Systems  

Microsoft Academic Search

Cognitive radio (CR) permits to satisfy the necessity of more efficiency in the radio spectrum occupation. An important task of CR is dynamic spectrum management of the transmitted signal to avoid the interference to\\/from the existent licensed in-band applications. We propose an adaptive modulation waveform for ultra-wideband (UWB) based CR systems in this paper. By controlling the time intervals between

Weihua Zhang; Hanbing Shen; Zhiquan Bai; Kyung Sup Kwak

2007-01-01

168

Spatial-Temporal Combining-Based ZF Detection in Ultra-Wideband Communications  

Microsoft Academic Search

The performance of ultra-wideband (UWB) multiple input multiple output (MIMO) receiver based on the RAKE maximal ratio combiner (MRC) followed by a zero forcing (ZF) detector is analytically examined. For a UWB MIMO system with NT transmit antennas, NR receive antennas, and L resolvable multipath components, the proposed MIMO detection scheme is shown to have the diversity order of LNR-NT+1

Jinyoung An; Sangchoon Kim

2009-01-01

169

Multiuser Channel Estimation for Ultra-Wideband Systems Using up to the Second-Order Statistics  

Microsoft Academic Search

In a pulse-position modulation-based ultra-wideband (UWB) communication system, multiple access is enabled by assigning unique time-hopping sequences to di erent users. Each user's data information is carried by positions of short pulses which are directly transmitted through an unknown and possibly dense multipath channel. Single-user channel estimation methods have been proposed by maximum likelihood optimization that treats multiple access interference

Zhengyuan Xu; Jin Tang; Ping Liu

2005-01-01

170

The ultra wideband transfer function representation of complex three-dimensional electromagnetic structures  

Microsoft Academic Search

the network-oriented ultra wideband transfer function representation of complex three-dimensional elec- tromagnetic structures is investigated. The transfer function is consisting of two parts: entire function and rational or pole function. The reduction of a rank of an ill-conditioned matrix is performed in accordance with the spectral crite- rion. System identification is carried out by the Matrix Pen- cil Method (MPM)

Yury Kuznetsov; Andrey Baev; Fabio Coccetti; Peter Russer

2004-01-01

171

Compact permittivity-matched ultra-wideband antennas for biomedical imaging  

Microsoft Academic Search

Ultra-wideband biomedical radar systems are an important means for the diagnostic inspection and monitoring of physiological signatures. Geometrically small antennas and high- resolution imaging techniques are required for such applications. We have developed compact ceramic double-ridged horn anten- nas for contact-mode measurements with a permittivity matched to human tissues. In the focus of the present work is the experi- mental

F. Scotto di Clemente; M. A. Hein; R. Stephan

2011-01-01

172

A novel design of an ultra-fast wideband polarimetric radar  

Microsoft Academic Search

Accurate high resolution measurements of both clutter and man-made targets at millimeter-wave frequencies have become an essential requirement for the development of optimal target detection and tracking algorithms. Towards this end, an ultra-fast wideband polarimetric instrumentation radar was developed by The University of Michigan for millimeter-wave frequencies applications. With this new design, the scattering matrix of a target can be

A. Nashashibi; K. Sarabandi; P. Frantzis; R. D. De Roo; F. T. Ulaby

1999-01-01

173

Ultra-wideband, short-pulse ground-penetrating radar: simulation and measurement  

Microsoft Academic Search

Ultra-wideband (UWB), short-pulse (SP) radar is investigated theoretically and experimentally for the detection and identification of targets buried in and placed atop soil. The calculations are performed using a rigorous, three-dimensional (3D) method of moments algorithm for perfectly conducting bodies of revolution. Particular targets investigated theoretically include anti-personnel mines, anti-tank mines, and a 55-gallon drum, for which the authors model

Stanislav Vitebskiy; Lawrence Carin; Marc A. Ressler; Francis H. Le

1997-01-01

174

Alternate bit reversal search for acquisition of ultra wide-band transmissions  

Microsoft Academic Search

Rapid acquisition of ultra wide-band (UWB) signals constitutes a major challenge because of the impulse-like short pulse at the sub-nanosecond scale, which results in a very wide uncertainty region of search. Recent studies have concluded that the process of acquiring the UWB signals can be expedited by the presence of multi-path. Acquisition analysis is made here by a generalized signal

Taeyoung Han; Nam Kim

2004-01-01

175

On Ultra-Wideband MIMO Systems with 1-bit Quantized Outputs: Performance Analysis and Input Optimization  

Microsoft Academic Search

We study the performance of multi-input multi-output (MIMO) channels with coarsely quantized outputs in the low signal-to-noise ratio (SNR) regime, where the channel is perfectly known at the receiver. This analysis is of interest in the context of Ultra-Wideband (UWB) communications from two aspects. First the available power is spread over such a large frequency band, that the power spectral

Amine Mezghani; Josef A. Nossek

2007-01-01

176

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

Microsoft Academic Search

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

John D. Choi; Wayne E. Stark

2002-01-01

177

Tomographic imaging with ultra-wideband noise radar using time-domain data  

NASA Astrophysics Data System (ADS)

This paper investigates the feasibility of using a noise waveform in an ultra-wideband (UWB) radar system for two-dimensional tomographic imaging of a stationary object with a multistatic tomographic geometry. Multiple UWB transmitters and receivers are positioned along each side of the imaging area. We perform several numerical simulations in time-domain, and the successful imaging of the target is achieved by visual inspection of the formed images.

Shin, Hee Jung; Narayanan, Ram M.; Rangaswamy, Muralidhar

2013-05-01

178

Fusion of magnetic resonance imaging and ultra-wideband-radar for biomedical applications  

Microsoft Academic Search

Due to the recent advances in ultra-wideband (UWB)-radar technologies, there has been widespread interest in medical applications of this technology. We propose the multimodal combination of magnetic resonance (MR) and UWB-radar for improved functional diagnosis and imaging. A demonstrator was established to prove the feasibility of simultaneous acquisition of physiological events by magnetic resonance imaging and UWB-radar.

Florian Thiel; Matthias Hein; Ulrich Schwarz; Jürgen Sachs; Frank Seifert

2008-01-01

179

Ultra-wideband circular polarized microstrip Archimedean spiral antenna loaded with chip-resistor  

Microsoft Academic Search

In this paper, an ultra-wideband (UWB) right hand circular polarized (RHCP) low-profile microstrip Archimedean spiral antenna operating with a chip-resistor load is presented. The radiating spiral patch is implemented on a typical FR4 printed circuit board (PCB) and is center fed through an SMA surface-mount connector. A chip-resistor loading at the outer edge of the spiral provides an excellent bandwidth

Christos Kinezos; Vichate Ungvichian

2003-01-01

180

Fusing ultra-wideband radar and lidar for small UGV navigation in all-weather conditions  

Microsoft Academic Search

Autonomous small UGVs have the potential to greatly increase force multiplication capabilities for infantry units. In order for these UGVs to be useful on the battlefield, they must be able to operate under all-weather conditions. For the Daredevil Project, we have explored the use of ultra-wideband (UWB) radar, LIDAR, and stereo vision for all-weather navigation capabilities. UWB radar provides the

Brian Yamauchi

2010-01-01

181

A low-power OOK ultra-wideband transmitter with power cycling and spectral flexibility  

Microsoft Academic Search

This paper presents a reconfigurable 0.13 ?m CMOS impulse radio ultra-wideband transmitter which supports the on-off keying modulation scheme. The transmitter allows for control of the center frequency and bandwidth of the output spectrum, thus providing large spectrum flexibility. A power cycling scheme is implemented to reduce the power consumption, and allows the system to operate within stringent power requirements.

Raslen Hamdi; Kamel Elkhenissi; Dominic Deslandes; Frederic Nabki

2010-01-01

182

Programmable Photonic Microwave Filters With Arbitrary Ultra-Wideband Phase Response  

Microsoft Academic Search

We present a coherent optical signal-processing approach for synthesis of programmable microwave phase filters over an ultra-wideband. Our scheme relies on a programmable optical phase filter implemented in a pulse-shaping geometry incorporating a spatial light modulator and hyperfine (~600-MHz spectral resolution) optical spectral disperser. The user-defined optical phase filter is directly transferred to the electrical domain through heterodyne conversion, and

Shijun Xiao; Andrew M. Weiner

2006-01-01

183

Recent system applications of short-pulse ultra-wideband (UWB) technology  

Microsoft Academic Search

Developed in the early 1960s, time-domain electromagnetics, the study of electromagnetic-wave propagation from a time-domain perspective, has given birth to a fascinating new technology, which today is commonly referred to as ultra-wideband (UWB). It has now been slightly more than 25 years since the 1978 seminal paper of Bennett and Ross, which summarized UWB's early applications. It thus seems appropriate,

Robert J. Fontana

2004-01-01

184

A Frequency Triplexer for Ultra-Wideband Systems Utilizing Combined Broadside and Edge-Coupled Filters  

Microsoft Academic Search

A fully integrated triplexer for multiband ultra-wideband radio is presented. The triplexer utilizes a microstrip network and three combined broadside- and edge-coupled filters. It is fully integrated in a printed circuit board with low requirements on the printed circuit board process tolerance. Three flat subbands in the frequency band 3.1-4.8 GHz have been achieved. The group delay variation within each

Magnus Karlsson; PÄr Hakansson; Shaofang Gong

2008-01-01

185

An ultra-wideband log-periodic vibrator of the mirror antenna  

Microsoft Academic Search

The paper is devoted to investigation of ultra-wideband logarithmically periodic vibrators of mirror antennas. The vibrators\\u000a have the form of cophasal antenna arrays consisting of two log-periodic dipole radiators, comprising a pyramid arranged in\\u000a the H-plane. The asymmetric and symmetric types of excitation of these dipoles are considered, with their calculated and measured\\u000a characteristics included.

F. F. Dubrovka; N. N. Litvin; S. Ye. Martynyuk; M. N. Bilanovskii; G. A. Yena

2007-01-01

186

Free space optical ultra-wideband communications over atmospheric turbulence channels  

Microsoft Academic Search

A hybrid impulse radio ultra-wideband (IR-UWB) communication system in which UWB pulses are transmitted over long distances through free space optical (FSO) links is proposed. FSO channels are characterized by random fluctuations mainly due to the atmospheric turbulence. For this reason, theoretical detection error probability analysis is presented for a time-hopping pulse-position modulated (TH-PPM) UWB signal model under weak, moderate

K. Davasliog?lu; E. C?ag?iral; M. Koca

2010-01-01

187

Coherent power combining of ultra-wideband pulsed radiation in free space  

Microsoft Academic Search

Photoconductive switches are used to trigger an array of three pulsed ultra-wideband antennas. The jitter-free pulses radiated by each antenna add together in free space to produce a radiated field pattern that is steerable via true optical time-delay techniques. This technique can be applied to an N-element phased array for increased radiated power and beam-steering capabilities

Eric E. Funk; Stephen E. Saddow; C. H. Lee

1995-01-01

188

Photonic generation of power-efficient FCC-compliant ultra-wideband waveforms using semiconductor optical amplifier (SOA): theoretical analysis and experiment verification  

NASA Astrophysics Data System (ADS)

We theoretically design a power-efficient ultra-wideband pulse generator by combining three monocycle pulses with different weights. We also experimentally demonstrate a feasible scheme to generate such power-efficient ultra-wideband waveforms using cross-phase modulation in a single semiconductor optical amplifier. The designed ultra-wideband pulse fully satisfies the requirements for the spectral mask specified by the Federal Communications Commission with high power efficiency. In the experiment, a power-efficient ultra-wideband waveform with a pulse duration of 310 ps is achieved, and the power efficiency is greatly improved compared with that of a single monocycle pulse or a mixture of two monocycles.

Dong, Jian-Ji; Luo, Bo-Wen; Huang, De-Xiu; Zhang, Xin-Liang

2012-04-01

189

Land mine detection with an ultra-wideband SAR system  

Microsoft Academic Search

PULSAR is an Ultra Wide Band (UWB) short pulse Radar developed by the CELAR (French Technical Center for Armament Electronics) and the IRCOM (Research Institute of Microwave and Optical Communications) in order to detect foliage and ground concealed mines. An instrumentation measurement system has been designed and implemented, in particular new 2D broad band antennas with a very low pulse

Joel Andrieu; Frederic Gallais; Vincent Mallepeyre; Valerie Bertrand; Bruno Beillard; Bernard Jecko; Regis Guillerey; Marc Legoff

2002-01-01

190

Ultra-Wideband GPR Imaging of the Vaucluse Karst Aquifer  

Microsoft Academic Search

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

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

2008-01-01

191

High power ultra wideband radar exotic material response  

Microsoft Academic Search

This paper is the first of two that present analytical and numerical analysis of high power and ultra wide band radars interacting with EMI and radar suppression materials. Magnetic materials are often used in isolators, thin film EMI materials and\\/or appliques. Such magnetic composites may be exposed to wide band and\\/or high power signals in operational radar systems. We describe

Rick L. Moore; John Meadors; Robert Rice

2008-01-01

192

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

193

Contemporary Wireless Technology  

NSDL National Science Digital Library

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

2012-08-21

194

Suppression of radio frequency inteference (RFI) for synchronous impulse reconstruction ultra-wideband radar  

NASA Astrophysics Data System (ADS)

This paper is concerned with the issues associated with the suppression of radio frequency interference (RFI) for a synchronous impulse reconstruction (SIRE) ultra-wideband (UWB) synthetic aperture radar (SAR) that is currently being designed and built at the Army Research Laboratory. In this effort, we are developing the next version of the UWB radar that can employ inexpensive A/D converters to digitize wideband signals using the equivalent time sampling technique. In this presentation, we provide an analytical model for the signature of the RFI sources that are measured via an equivalent time sampling scheme. This formulation reveals spectral as well as temporal properties of the measured RFI signals that would aid a user in developing sniff (passive) data collection strategies for constructing adaptive digital signal processing methods for suppressing RFI sources.

Nguyen, Lam; Soumekh, Mehrdad

2005-05-01

195

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

196

Analysis of Ultra-wideband Impulse Radio Over Multimode Fiber Ranging System  

Microsoft Academic Search

\\u000a Ultra-wideband impulse radio (UWB-IR)-based systems are well known for their inherent capability to provide accurate ranging\\u000a [1–3]. Remote positioning of such systems using Radio over MultiMode Fiber (RoMMF) technology is advantageous, for it provides\\u000a a cost-effective way of system deployment by the consolidation of head-end equipment. In this chapter, we describe the details\\u000a of a system model for evaluating the

J. George; D. Thelen; A. Chamarti; A. Ng’oma; M. Sauer

2010-01-01

197

A photonic ultra-wideband pulse generator based on relaxation oscillations of a semiconductor laser.  

PubMed

A photonic ultra-wideband (UWB) pulse generator based on relaxation oscillations of a semiconductor laser is proposed and experimentally demonstrated. We numerically simulate the modulation response of a direct modulation laser (DML) and show that due to the relaxation oscillations of the laser, the generated signals with complex shape in time domain match the Federal Communications Commission (FCC) mask in the frequency domain. Experimental results using a DML agree well with simulation predictions. Furthermore, we also experimentally demonstrate the generation of FCC compliant UWB signals by externally injecting a distributed feedback (DFB) laser. PMID:19506617

Yu, Xianbin; Braidwood Gibbon, Timothy; Pawlik, Michal; Blaaberg, Søren; Tafur Monroy, Idelfonso

2009-06-01

198

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.

Rotaru, Mihai; Sykulski, Jan

2010-01-01

199

Chaotic ultra-wideband radio generator based on an optoelectronic oscillator with a built-in microwave photonic filter.  

PubMed

We induce a microwave photonic bandpass filter into an optoelectronic oscillator to generate a chaotic ultra-wideband signal in both the optical and electrical domain. The theoretical analysis and numerical simulation indicate that this system is capable of generating band-limited high-dimensional chaos. Experimental results coincide well with the theoretical prediction and show that the power spectrum of the generated chaotic signal basically meets the Federal Communications Commission indoor mask. The generated chaotic carrier is further intensity modulated by a 10 MHz square wave, and the waveform of the output ultra-wideband signal is measured for demonstrating the chaotic on-off keying modulation. PMID:22614596

Wang, Li Xian; Zhu, Ning Hua; Zheng, Jian Yu; Liu, Jian Guo; Li, Wei

2012-05-20

200

100 GHz ultra-wideband (UWB) fiber-to-the-antenna (FTTA) system for in-building and in-home networks.  

PubMed

Fiber-to-the-antenna (FTTA) system can be a cost-effective technique for distributing high frequency signals from the head-end office to a number of remote antenna units via passive optical splitter and propagating through low-loss and low-cost optical fibers. Here, we experimentally demonstrate an optical ultra-wideband (UWB) - impulse radio (IR) FTTA system for in-building and in-home applications. The optical UWB-IR wireless link is operated in the W-band (75 GHz - 110 GHz) using our developed near-ballistic unitraveling-carrier photodiode based photonic transmitter (PT) and a 10 GHz mode-locked laser. 2.5 Gb/s UWB-IR FTTA systems with 1,024 high split-ratio and transmission over 300 m optical fiber are demonstrated using direct PT modulation. PMID:20173867

Chow, C W; Kuo, F M; Shi, J W; Yeh, C H; Wu, Y F; Wang, C H; Li, Y T; Pan, C L

2010-01-18

201

A Comprehensive Evaluation of Joint Range and Angle Estimation in Ultra-Wideband Location Systems for Indoors  

Microsoft Academic Search

Fine time resolution enables Ultra-Wideband (UWB) ranging systems to reliably extract the first multipath arrival corresponding to the range between a transmitter and receiver, even when attenuated in strength compared to later arrivals. Bearing systems alone lack any notion of time and in general select the arrival coinciding with the strongest path, which is rarely the first one in non

Camillo Gentile; A. Judson Braga; Alfred Kik

2008-01-01

202

Towards a design of the ultra-wideband microwave devices using the non-foster negative reactances  

Microsoft Academic Search

A novel simple and efficient approach to a design of the ultra-wideband (UWB) microwave devices using the non-Foster negative reactances implemented as the transistor negative impedance converters is presented. Series as well as parallel connection of the positive inductance and negative capacitance (or vice versa) allows providing the sum reactance with only a small variation over a wide frequency band.

Dmitry V. Kholodnyak; Viacheslav M. Turgaliev

2012-01-01

203

Capacity-maximizing resource allocation for data-aided timing and channel estimation in ultra-wideband radios  

Microsoft Academic Search

The overall system performance of data-aided ultra-wideband (UWB) 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 symbols in order to strike a desired balance between performance and information rate. To this end, this paper derives optimum transmission schemes that judiciously allocate

Lin Wu; Zhi Tian

2004-01-01

204

A review on modulation techniques in multiband-orthogonal frequency division multiplexing in ultra-wideband channel  

Microsoft Academic Search

This paper describes a review on mapping or modulation techniques used in multiband orthogonal frequency division multiplexing (MB-OFDM) in ultra- wideband (UWB) channel. QAM, BPSK and QPSK modulation techniques are commonly used in this system due to their smooth power spectrum, low bit error rate (BER) and low receiver complexity. The new constant envelop modulation technique is proposed since it

Chempaka Mohd Din; Wahidah Mansor; Roslina Mohamad

2011-01-01

205

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.

Thiel, Florian; Kosch, Olaf; Seifert, Frank

2010-01-01

206

Generation of an ultra-wideband triplet signal based on semiconductor optical amplifier  

NASA Astrophysics Data System (ADS)

We propose a novel ultra-wideband (UWB) triplet signal source based on the cross-gain modulation (XGM) in semiconductor optical amplifier (SOA). In the proposed scheme, only an optical source and two SOAs are needed, so the all-optical structure is compact. A triplet optical pulse with center frequency of 6.25 GHz and fractional bandwidth of 83% is obtained by the scheme. The extinction ratio can be improved by the counter-propagating scheme. The triplet pulse signal with only one wavelength can be easily controlled, and can aviod the dispersion effect. The output triplet pulse signal is insensitive to the light wavelength shifts, its available wavelength range is wide, the dynamic range of the input power is more than 6 dBm, and the bias current of the SOAs is exhibited.

Ma, Qiang; Li, Pei-li; Zheng, Jia-jin; Shen, Dan-hong; Zhao, Meng; Zhou, Wen; Zhao, Zan-shan

2013-05-01

207

Photonic generation of power-efficient ultra-wideband waveforms using a single semiconductor optical amplifier  

NASA Astrophysics Data System (ADS)

A novel photonic generation of power-efficient ultra-wideband (UWB) pulse by combining two asymmetric monocycle pulses with inverted polarities is experimentally demonstrated. The principle lies in cross-phase modulation (XPM) in a single semiconductor optical amplifier (SOA) and phase modulation to intensity modulation conversions in an arrayed-waveguide grating (AWG). The Federal Communications Committee (FCC) compliant UWB pulse gains 24.3 dB and 20.8 dB improvements compared to positive and negative monocycle pulses after power attenuation to respect the FCC spectral mask, respectively. The generated power-efficient UWB with pulse duration of about 310 ps has potential to achieve high speed transmission and modulation without overlapping and distortion.

Dong, Jianji; Zhang, Yin; Yu, Yuan; Huang, Dexiu; Zhang, Xinliang

2010-12-01

208

Safety assessment of ultra-wideband antennas for microwave breast imaging.  

PubMed

This article deals with the safety assessment of several ultra-wideband (UWB) antenna designs for use in prototype microwave breast imaging systems. First, the performances of the antennas are validated by comparison of measured and simulated data collected for a simple test case. An efficient approach to estimating the specific energy absorption (SA) is introduced and validated. Next, SA produced by the UWB antennas inside more realistic breast models is computed. In particular, the power levels and pulse repetition periods adopted for the SA evaluation follow the measurement protocol employed by a tissue sensing adaptive radar (TSAR) prototype system. Results indicate that the SA for the antennas examined is below limits prescribed in standards for exposure of the general population; however, the difficulties inherent in applying such standards to UWB exposures are discussed. The results also suggest that effective tools for the rapid evaluation of new sensors have been developed. PMID:21826686

De Santis, Valerio; Sill, Jeff M; Bourqui, Jeremie; Fear, Elise C

2011-08-08

209

Adaptive low-rank channel estimation for multi-band OFDM ultra-wideband communications  

NASA Astrophysics Data System (ADS)

In this paper, an adaptive channel estimation scheme based on the reduced-rank (RR) Wiener filtering (WF) technique is proposed for multi-band (MB) orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) communication systems in multipath fading channels. This RR-WF-based algorithm employs an adaptive fuzzy-inference-controlled (FIC) filter rank. Additionally, a comparative investigation into various channel estimation schemes is presented as well for MB-OFDM UWB communication systems. As a consequence, the FIC RR-WF channel estimation algorithm is capable of producing the bit-error-rate (BER) performance similar to that of the full-rank WF channel estimator and superior than those of other interpolation-based channel estimation schemes.

Hu, Chia-Chang; Lee, Shih-Chang

2011-12-01

210

Elderly-Care Motion Monitoring Sensor Using Ultra-wideband Radio  

NASA Astrophysics Data System (ADS)

Requirement for monitoring the state of the elderly in care facilities is increasing year by year and the increase in accidents involving them becomes great concern. In this paper, an ultra-wideband impulse-radio monitoring sensor is suggested which focuses on the bed state most critical to the elderly that need the assistance immediately. Employing our developed state estimation algorithm, various states can be detected that includes sleeping in bed, sitting up in bed and going in and out from the room. The measurements were conducted in a room assumed the care facilities and the performance is investigated where various scenarios are considered. The measurement result shows that the detection rate is more than 91%.

Ota, Kyohei; Otsu, Mitsugu; Ota, Yuki; Kajiwara, Akihiro

211

3D SAR image formation for underground targets using ultra-wideband (UWB) radar  

NASA Astrophysics Data System (ADS)

This paper analyzes the application of ultra-wideband ground-penetrating radar (GPR) in a down-looking configuration for the detection of buried targets. As compared to previous studies, where target detection algorithms have been developed based on the radar range profiles alone (pre-focus data), we investigate the potential performance improvement by forming synthetic aperture radar (SAR) images of the targets. This becomes important in scenarios with small signal-to-noise or signal-to-clutter ratios. Our three-dimensional (3-D) image formation algorithm is based on the backprojection technique. We apply this method to radar scattering data obtained through computer simulation by the finite-difference time-domain (FDTD) technique. Our analysis demonstrates the advantages of using focused SAR images versus the pre-focus range profiles. We also perform a parametric study of several physical factors that could affect the image quality.

Nguyen, Lam; Dogaru, Traian; Innocenti, Roberto

2009-05-01

212

Non-invasive respiration rate estimation using ultra-wideband distributed cognitive radar system.  

PubMed

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare, rescue, and security applications. In this paper, a geometry-based statistical channel model is developed for simulating the reception of UWB signals in the indoor propagation environment. This model enables replication of time-varying multipath profiles due to the displacement of a human chest. Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate. The analytical framework can serve as a basis in the planning and evaluation of future measurement programs. PMID:17945609

Chen, Yifan; Gunawan, Erry; Low, Kay Soon; Kim, Yongmin; Soh, Cheong Boon; Leyman, A Rahim; Thi, Lin Lin

2006-01-01

213

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

214

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

PubMed Central

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

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

2011-01-01

215

An adaptive 2.4 GHz low-IF receiver in 0.6 ?m CMOS for wideband wireless LAN  

Microsoft Academic Search

High bit-rate communications require wideband channels and complex modulation schemes, such as QAM, to convey multiple bits per symbol. Available bandwidth (BW) and desired user density per cell together determine the BW allocated per channel. In short-range applications like indoor wireless LAN where transmitted power is limited to 1 mW, FCC rules allow channel BW higher than 1 MHz. This

F. Behbahani; J. Leete; Weeguan Tan; Y. Kishigami; A. Karimi-Sanjaani; A. Roithmeier; K. Hoshino; A. Abidi

2000-01-01

216

Synthesis of ultra-wideband bandpass filter prototype with multi-stage SIRs and short-circuited stubs loaded at ports  

Microsoft Academic Search

A new filter prototype consisting of multistage one-wavelength stepped-impedance resonators (SIRs) and two short-circuited stubs located at both ends was proposed based on the synthesis theory to achieve an ultra-wideband passband filter. With this prototype, a ultra-wideband bandpass (UWB) filter with the fractional bandwidth of 110% was synthesized to meet FCC's (Federal Communications Commission) outdoor frequency mask. The measured frequency

Chun-Ping Chen; Hiroshige NIHEI; Zhewang Ma; Tetsuo ANADA; Deming Xu

2008-01-01

217

Digital post-linearization of a Wideband Low Noise Amplifier for ultra-wideband wireless receivers  

Microsoft Academic Search

The scaling of CMOS Low Noise Amplifiers (LNA) comes with a reduction in supply voltage and increase in field mobility effect resulting in deterioration in linearity. This trade- off between CMOS transistor scaling and linearity is becoming more and more important as we transition into nano-scale CMOS LNA architectures. As a result, new techniques for the linearization of LNAs while

Ifiok Umoh; Tokunbo Ogunfunmi

2011-01-01

218

The physical foundation, developmental history, and ultra-wideband performance of SMM (spiral-mode microstrip) antennas  

Microsoft Academic Search

The paper reviews the physical foundation, developmental history, and ultra-wideband (UWB) performance of the SMM (spiral-mode microstrip) antenna (Wang, J.J.H. and Tripp, V.K., 1996; Wang, 1997; Wang et al., 2005). The paper is inspired by the recent article on self-complementary (SC) antennas by Y.Mushiake (see IEEE Antennas and Propag. Magazine, vol.46, 2004; IEEE Antennas and Propag. Symp. Dig., 2003), and

Johnson J. H. Wang

2005-01-01

219

Drosophila melanogaster viability and mutability under the influence of low energy microwave monochromatic and ultra wideband impulse field  

Microsoft Academic Search

The influence of microwave radiation (int = 35 GHz, intensity P = 30, 70, 180, 265 mW \\/cm2) and ultra wideband irradiation at irradiation intensity of 10-5, 10-4, 10 -3, and 10-2 W\\/cm2 on stocks of Drosophila melanogaster was investigated. Irradiation was performed on the stage of egg< exposure time was 10 sec... Irradiation by monochromatic radiation (35 GHz) of

Yuriy Shckorbatov; Vladimir Pasiuga; Lyubov Shakina; Valentin Grabina; Nikolai Kolchigin; Dmitrij Ivanchenko; Oleg Kazansky; Viktor Bykov

2007-01-01

220

Planar Ultra-Wideband Antennas in Ku- and K-Band for Pattern or Polarization Diversity Applications  

Microsoft Academic Search

Two planar diversity antennas operating in Ku- (12.4–18 GHz) and K-band (18–26.5 GHz) are proposed for ultra-wideband (UWB) applications. Both of them consist of a monopole radiating element and two orthogonal feeding ports. Their ground planes are modified and optimized to improve the isolation as well as to control the radiation. The first one is a pattern diversity antenna with

Yuandan Dong; Tatsuo Itoh

2012-01-01

221

Ultra-wideband time-delay line inspired by composite right\\/left-handed transmission line unit cell  

Microsoft Academic Search

This paper presents a design of ultra-wideband time-delay line inspired by the composite right\\/left-handed transmission line (CRLH TL) unit cell. A rotated version of the conventional CRLH TL unit cell is used to increase the operating bandwidth. The time-delay line is optimized using computer simulation and then fabricated on a PCB for measurement. For comparison, the time-delay lines using the

J. Zhang; S. W. Cheung; T. I. Yuk

2010-01-01

222

High-Speed Photonic Power-Efficient Ultra-Wideband Transceiver Based on Multiple PM-IM Conversions  

Microsoft Academic Search

We experimentally demonstrate a novel photonic ultra-wideband (UWB) transceiver with pulse spectral efficiency of 50.97% and transmission speed up to 3.125 Gb\\/s. The UWB generator only consists of a highly nonlinear fiber (HNLF) and a commercial arrayed-waveguide grating (AWG). By using the concept of multiple cross-phase modulation in the HNLF and multiple phase modulation to intensity modulation conversions in the

Enbo Zhou; Xing Xu; King-Shan Lui; Kenneth Kin-Yip Wong

2010-01-01

223

The performance of ultra wideband acquisition system based on energy detection over IEEE 802.15.3a channel  

Microsoft Academic Search

In this paper, we propose a theoretical framework to analyze the performance of ultra wideband acquisition (UWB) system based\\u000a on energy detection (ED) over IEEE 802.15.3a channel. The proposed framework enables to calculate probability density function\\u000a (PDF) of square-sum of multipath components (MPCs) gain collected by receiver, and the averaged criteria. In particular, the\\u000a expectation and variance of the sum

ZhiHua Yang; QinYu Zhang; NaiTong Zhang; Ye Wang

2011-01-01

224

Ultra-Wideband Signal Impact on the Performances of IEEE 802.11b and Bluetooth Networks  

Microsoft Academic Search

This paper presents the results of a coexistence study investigating the impact of ultra-wideband (UWB) interference on IEEE 802.11b and Bluetooth networks. The results are based on the experimental test measurements made at the University of Oulu, Finland. Simple high-power UWB transmitters are used to interfere with victim networks. Preliminary results show that only under extreme interference conditions with thousands

Matti Hämäläinen; Jani Saloranta; Juha-pekka Mäkelä; Ian Oppermann; Tero Patana

2003-01-01

225

Design of an ESD-Protected Ultra-Wideband LNA in Nanoscale CMOS for Full-Band Mobile TV Tuners  

Microsoft Academic Search

This paper presents an electrostatic discharge (ESD)-protected ultra-wideband (UWB) low-noise amplifier (LNA) for full-band (170-to-1700 MHz) mobile TV tuners. It features a PMOS-based open-source input structure to optimize the I\\/O swings under a mixed-voltage ESD protection while offering an inductorless broadband input impedance match. The amplification core exploiting double current reuse and single-stage thermal-noise cancellation enhances the gain and noise

Pui-In Mak; Rui Martins

2009-01-01

226

Joint TOA and AOA\\/AOD Spectrum for Ultra-Wideband Indoor Double-Directional Channel Estimation  

Microsoft Academic Search

This paper presents an ultra-wideband (UWB) double-directional channel sounding technique using transformation between time domain (TD) and frequency domain (FD) signals. We proposed the time-of-arrival (TOA), angle-of- arrival (AOA) estimation algorithm and angle-of-departure (AOD) with some modifications of our previous work. There were four main advantages of the proposed estimation technique as follows: implementation of the simple antenna array with

Naohiko Iwakiri; Takehiko Kobayashi

2008-01-01

227

Development and testing of bulk photoconductive switches used for ultra-wideband, high-power microwave generation  

Microsoft Academic Search

The Air Force Phillips Laboratory, in collaboration with the Army Research Laboratory (ARL), is developing lateral geometry, high-power photoconductive semiconductor switches (PCSS) for use in phased-array, ultra-wideband (UWB) sources. The current switch utilizes an opposed contact geometry with a 0.25 cm gap spacing and is an extension of previous work on 1.0 cm PCSS devices. This work presents the development

J. W. Burger; J. S. H. Schoenberg; J. S. Tyo; M. D. Abdalla; S. M. Ahern; M. C. Skipper; W. R. Buchwald

1997-01-01

228

FDTD analysis of a gigahertz TEM cell for ultra-wideband pulse exposure studies of biological specimens  

Microsoft Academic Search

Gigahertz transverse electromagnetic (GTEM) transmission cells have been previously used to experimentally study exposure of biological cells to ultra-wideband (UWB), monopolar, electromagnetic pulses. Using finite-difference time-domain (FDTD) simulations we examine the time-dependent electric field waveforms and energy dose spatial distributions within a finite volume of biological cell culture medium during these experiments. The simulations show that when one or more

Zhen Ji; C. Hagness; H. Booske; Satnam Mathur; Martin L. Meltz

2006-01-01

229

Unification of ultra-wideband data acquisition and real-time monitoring in LHD steady-state experiments  

Microsoft Academic Search

To support the steady-state plasma experiments in LHD, new functions have been developed for the LABCOM data acquisition system. Using new WE7000 and PXI digitizers for continuous ultra-wideband data acquisition at 80MB\\/s, the system is now able to perform data acquisition, storage, and server-to-client transfer fully in real-time. To manage the high amount of data for long-pulse experiments, the system

M. Ohsuna; H. Nakanishi; S. Imazu; M. Kojima; M. Nonomura; M. Emoto; Y. Nagayama; H. Okumura

2006-01-01

230

Low-loss ultra-wideband transition between conductor-backed coplanar waveguide and substrate integrated waveguide  

Microsoft Academic Search

A novel transition between conductor-backed coplanar waveguide (CBCPW) and substrate integrated waveguide (SIW) is presented for microwave and millimeter-wave integrated circuit design. The proposed integrated transition that can provide simultaneous field and impedance matching, exhibits outstanding low-loss performances over an ultra-wideband range (entire Ka-band in our case). In this work, a generalized impedance inverter whose parameters are accurately extracted by

Xiao-Ping Chen; Ke Wu

2009-01-01

231

Compact ultra-wideband antenna with inverted U-shaped slot and parachute-like radiation patch  

Microsoft Academic Search

A simple and compact wide-slot antenna for ultra-wideband application is presented. The antenna consists of an inverted U-shaped slot on a printed circuit board ground plane and a parachute-like radiation patch which is fed by a 50-? microstrip line. The antenna is built on a standard low-cost FR4 substrate with a whole size of 22?30?1 mm3. The measured and simulated

Ling Xiong; Peng Gao

2012-01-01

232

Multi-aspect detection of surface and shallow-buried unexploded ordnance via ultra-wideband synthetic aperture radar  

Microsoft Academic Search

An ultra-wideband (UWB) synthetic aperture radar (SAR) system is investigated for the detection of former bombing ranges, littered by unexploded ordnance (UXO). The objective is detection of a high enough percentage of surface and shallow-buried UXO, with a low enough false-alarm rate, such that a former range can be detected. The physics of UWB SAR scattering is exploited in the

Yanting Dong; Paul R. Runkle; Lawrence Carin; Raju Damarla; Anders Sullivan; Marc A. Ressler; Jeffrey Sichina

2001-01-01

233

A Ultra-Wideband Amplitude Modulation (AM) Detector Using Schottky Barrier Diodes Fabricated in Foundry CMOS Technology  

Microsoft Academic Search

Utility of Schottky diodes fabricated in foundry digital 130-nm CMOS technology is demonstrated by implementing an ultra-wideband (UWB) amplitude modulation detector consisting of a low-noise amplifier (LNA), a Schottky diode rectifier, and a low-pass filter. The input and output matching of the detector is better than -10 dB from 0-10.3 GHz and 0-1.7 GHz, respectively, and almost covers the entire

Swaminathan Sankaran; Kenneth K. O

2007-01-01

234

DESIGN OF AN ULTRA-WIDEBAND, LOW-NOISE AMPLIFIER USING A SINGLE TRANSISTOR: A TYPICAL APPLICATION EXAMPLE  

Microsoft Academic Search

In this work, a design method of an Ultra-Wideband (UWB), low-noise amplifler (LNA) is proposed exerting the perfor- mance limitations of a single high-quality discrete transistor. For this purpose, the compatible (Noise F, Input VSWR Vi, Gain GT) triplets and their (ZS, ZL) terminations of a microwave transistor are exploited for the feasible design target space with the minimum noise

Salih Demirel; F. Gune; Ufuk Ozkaya

2009-01-01

235

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.

Marinkovic, Stevan; Popovici, Emanuel

2012-01-01

236

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

2012-06-08

237

A Heterogeneous High Speed Wireless Body Sensor Network Based on SC-UWB and ZIGBEE  

Microsoft Academic Search

Some new medical applications, such as wireless endoscopy system for the diagnoses of whole human digestive tract and real-time endoscopic image monitoring, demand high speed transmission in wireless body sensor network (WBSN). This paper proposes a heterogeneous high speed wireless body sensor network based on ZIGBEE and single carrier ultra wideband (SC-UWB). Our system can choose high speed mode or

Xinlei Chen; Xiyu Lu; Zhongjin Liu; Shaoxia Fang; Depeng Jin; Lieguang Zeng

2011-01-01

238

A wideband dual-antenna receiver for wireless recording from animals behaving in large arenas.  

PubMed

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 ?V rms 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; Ghovanloo, Maysam

2013-02-15

239

Accurate Permittivity Measurements for Microwave Imaging via Ultra-Wideband Removal of Spurious Reflectors  

PubMed Central

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 estimate of the variability of the hidden material, such internal moisture, thereby alerting personnel to damaging levels of the hidden moisture before material degradation occurs. One impediment to this type of imaging occurs with nearby objects create strong reflections that create destructive and constructive interference, at the receiver, as the material is conveyed past the imaging antenna array. In an effort to remove the influence of the reflectors, such as metal bale ties, research was conducted to develop an algorithm for removal of the influence of the local proximity reflectors from the microwave images. This research effort produced a technique, based upon the use of ultra-wideband signals, for the removal of spurious reflections created by local proximity reflectors. This improvement enables accurate microwave measurements of moisture in such products as cotton bales, as well as other physical properties such as density or material composition. The proposed algorithm was shown to reduce errors by a 4:1 ratio and is an enabling technology for imaging applications in the presence of metal bale ties.

Pelletier, Mathew G.; Viera, Joseph A.; Wanjura, John; Holt, Greg

2010-01-01

240

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

241

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

PubMed

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 estimate of the variability of the hidden material, such internal moisture, thereby alerting personnel to damaging levels of the hidden moisture before material degradation occurs. One impediment to this type of imaging occurs with nearby objects create strong reflections that create destructive and constructive interference, at the receiver, as the material is conveyed past the imaging antenna array. In an effort to remove the influence of the reflectors, such as metal bale ties, research was conducted to develop an algorithm for removal of the influence of the local proximity reflectors from the microwave images. This research effort produced a technique, based upon the use of ultra-wideband signals, for the removal of spurious reflections created by local proximity reflectors. This improvement enables accurate microwave measurements of moisture in such products as cotton bales, as well as other physical properties such as density or material composition. The proposed algorithm was shown to reduce errors by a 4:1 ratio and is an enabling technology for imaging applications in the presence of metal bale ties. PMID:22163668

Pelletier, Mathew G; Viera, Joseph A; Wanjura, John; Holt, Greg

2010-09-10

242

FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses.  

PubMed

With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW. PMID:18367803

Simicevic, Neven

2008-03-07

243

Fusing ultra-wideband radar and lidar for small UGV navigation in all-weather conditions  

NASA Astrophysics Data System (ADS)

Autonomous small UGVs have the potential to greatly increase force multiplication capabilities for infantry units. In order for these UGVs to be useful on the battlefield, they must be able to operate under all-weather conditions. For the Daredevil Project, we have explored the use of ultra-wideband (UWB) radar, LIDAR, and stereo vision for all-weather navigation capabilities. UWB radar provides the capability to see through rain, snow, smoke, and fog. LIDAR and stereo vision provide greater accuracy and resolution in clear weather but has difficulty with precipitation and obscurants. We investigate the ways in which the sensor data from UWB radar, LIDAR, and stereo vision can be combined to provide improved performance over the use of a single sensor modality. Our research includes both traditional sensor fusion, where data from multiple sensors is combined in a single representation, and behavior-based sensor fusion, where the data from one sensor is used to activate and deactivate behaviors using other sensor modalities. We use traditional sensor fusion to combine LIDAR and stereo vision for improved obstacle avoidance in clear air, and we use behavior-based sensor fusion to select between radar-based and LIDAR/vision-based obstacle avoidance based on current environmental conditions.

Yamauchi, Brian

2010-04-01

244

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

245

Design, Investigation and Measurement of A Compact Ultra Wideband Antenna for Portable Applications  

NASA Astrophysics Data System (ADS)

The design of a printed compact planar antenna of asymmetrical structure with ultra wide bandwidth is described and investigated in this paper. The antenna provides more than 114% impedance bandwidth below VSWR 2 (from 3.3 to more than 12 GHz) with a center frequency of 7.65 GHz; thus it covers the bandwidth requirement for portable UWB wireless device applications. The structure of the asymmetric proposed antenna is very simple and composed of a small hexagonal shaped patch with two asymmetrical coplanar ground planes. It occupies an area of only 20 × 24.5 mm2 when printed on one side of an FR4 substrate with a thickness of 1.6 mm.

Mobashsher, Ahmed Toaha; Islam, Mohammad Tariqul

2013-08-01

246

Ultra-miniature wireless temperature sensor for thermal medicine applications  

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

247

Focus of attention for millimeter and ultra wideband synthetic aperture radar imagery  

NASA Astrophysics Data System (ADS)

The major goal of this research is to develop efficient detectors for Synthetic Aperture Radar (SAR) images, exploiting the reflectivity characteristics of targets in different radar types. Target detection is a signal processing problem whereby one attempts to detect a stationary target embedded in background clutter while minimizing the false alarm probability. In radar signal processing, the better resolution provided by the Millimeter Wave (MMW) SAR enhances the detectability of small targets. As radar technology evolves, the newly developed Ultra Wideband (UWB) SAR provides better penetration capabilities to locate concealed targets in foliage. In this thesis we demonstrate that local intensity kernel tests can be formulated based on the generalized likelihood ratio test (GLRT), while preserving constant false alarm rate (CFAR) characteristics. Both the widely used two-parameter CFAR and the g -CFAR can be viewed as special cases of the local intensity tests with different intensity kernels. It is demonstrated that the first-order Gamma kernel is a good approximation for the principal eigenvector of the projected radial intensity of targets, which provides the optimal matching intensity kernel. This also explains the better performance of the g -CFAR detector over the two parameter CFAR detector. We also developed different CFAR subspace detectors for UWB images, utilizing a Laguerre function subspace. The driven response produced by natural clutter degrades the performance of these subspace detectors. In addition to the driven response, the distinguishing feature of metallic targets in UWB is the resonance response. Therefore, we further propose a two-stage detection scheme: g -CFAR detector followed by the quadratic Laguerre discriminator (QLD). We evaluate every detector and discriminator using ROC curves in a large area (about 2 km2) of imagery. The combined g -CFAR and quadratic Laguerre discriminator improve the simple Laguerre subspace detector more than one hundred fold for a perfect detection rate (Pd = 1).

Yen, Li-Kang

248

Ultra-wideband pulse generation with flexible pulse shape and polarity control using a Sagnac-interferometer-based intensity modulator.  

PubMed

We propose a novel scheme to generate ultra-wideband (UWB) pulse by employing a Sagnac interferometer comprising a phase modulator. This structure performs a dual-input and dual-output intensity modulator (IM), ultimately resulting in the flexibility to select the shape and the polarity of the generated UWB pulse. The experiment results show a good agreement with the theoretical investigation in terms of both pulse profile and spectrum, which conforms to the definition of UWB signals by the U.S. Federal Communications Commission. Furthermore, the proposed scheme is independent of the voltage bias point. PMID:19551113

Li, Jianqiang; Xu, Kun; Fu, Songnian; Wu, Jian; Lin, Jintong; Tang, Ming; Shum, P

2007-12-24

249

Ultra-wideband coaxial hybrid coupler for load resilient ion cyclotron range of frequency heating at fusion plasmas  

SciTech Connect

We designed a high power and ultra-wideband two-section 3 dB coaxial hybrid coupler for load resilient ion cyclotron range of frequency heating by configuring asymmetric impedance matching using a three-dimensional simulation code, hfss. By adjusting the characteristic impedances of main and coupled lines of the hybrid coupler, we realized that the bandwidth of the proposed circuit is not only wider than that of a conventional three-section coupler, but also that the bandwidth is almost twice as wide compared to the conventional two-section hybrid coupler while maintaining the identical overall size.

Kim, H. J.; Bae, Y. S.; Yang, H. L.; Kwak, J.-G. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Wang, S. J. [Korea Atomic Energy Research Institute, Daejeon 305-333 (Korea, Republic of); Kim, B. K.; Choi, J. J. [Department of Electronics Convergence Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

2012-06-25

250

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

251

Comprehensive model-based error analysis of multiple concurrent, time-interleaved, and hybrid ultra-wideband analogue-to-digital conversion  

Microsoft Academic Search

In this paper, a comprehensive parametric error model of ultra-wideband analogue- to-digital conversion (ADC) is developed, which can likewise be applied for single ultra-fast ADC, multiple concurrent ADC (MC-ADC), time-interleaved ADC (TI- ADC) and hybrid ADC (H-ADC) as a combination of TI- and MC-ADC. The error model comprises quantisation, overo w saturation, DC-oset, gain error, time de- lay, and time

Heiko Kopmann

2004-01-01

252

Miniature double-ridged horn antennas composed of solid high-permittivity sintered ceramics for biomedical ultra-wideband radar applications  

Microsoft Academic Search

Ultra-wideband (UWB) radar sensors are attracting more and more attention, e.g., for biomedical applications. In contrast to established techniques like X-ray tomography or invasive diagnostic approaches, UWB radar offers the potential for remote access and ultra-low power signal intensities. Inspired by promising studies of breast tumor imaging, we are continuing and extending our previous work on biomedical M-sequence radar and

Ulrich Schwarz; Ralf Stephan; Matthias A. Hein

2010-01-01

253

Real-time kinematic surveying using tightly-coupled GPS and ultra-wideband ranging  

NASA Astrophysics Data System (ADS)

Ultra-wideband (UWB) ranging radios, an emerging technology that offers precise, short distance, range measurements are investigated as a method to augment carrier-phase GPS positioning. This thesis begins with a discussion of radio-frequency based methods of augmenting high precision GPS and proposes to utilize UWB ranging technology in a tightly-coupled GPS and UWB position estimation filter. This thesis then provides an overview of UWB in the context of ranging applications and assesses the precision and accuracy of UWB ranging from both a theoretical perspective and a practical perspective using real data. Two types of commercially available UWB ranging radios are introduced which are used in testing. Actual ranging accuracy is assessed from line-of-sight testing in benign signal conditions and in outdoor testing with line-of-sight obstructions and strong reflection sources. A tightly-coupled GPS and UWB real-time kinematic (RTK) estimation method is developed and the performance of the system is evaluated in static and kinematic testing. The results of static testing show that the integrated solution provides better accuracy, better ability to resolve integer ambiguities and enhanced fixed ambiguity solution availability compared with GPS alone. The results of kinematic testing demonstrate that UWB errors can be successfully estimated in a real-time filter. In static and kinematic testing in a degraded GPS environment created by artificially inducing a 40° satellite elevation mask, subdecimetre accuracy was maintained. The tightly-coupled system is also tested to survey several external corner points of an eight story building. The tightly-coupled solution is compared to GPS-only, UWB-only, and loosely-coupled solutions. Sub-metre level solutions are maintained using tight-coupling in conditions where the solutions from the other three approaches are either unavailable or unreliable. The thesis also provides a novel and efficient method for deploying UWB reference stations and performing the RTK survey. Tightly-coupled GPS+UWB for RTK surveying is a promising new technology that extends RTK surveying to new environments. In addition, in marginal GPS-only surveying environments, position accuracy and RTK solution availability are improved substantially.

Macgougan, Glenn D.

254

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

255

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

256

Detection of obscured targets in heavy-tailed radar clutter using an ultra-wideband (UWB) radar and alpha-stable clutter models  

Microsoft Academic Search

The use of an ultra-wideband (UWB) synthetic aperture radar (SAR) for detection of buried or obscured targets is an intense area of research because of the penetration and high-resolution capabilities of the radar. We address the important question of clutter modeling. More specifically, we examine the clutter observed from a forest for robust detection of targets that are buried in

R. Kapoor; G. A. Tsihrintzis; N. Nanclhakumar

1996-01-01

257

Beyond 3G: wideband wireless data access based on OFDM and dynamic packet assignment  

Microsoft Academic Search

ABSTRACT The rapid growth of wireless voice sub scribers, the growth of the Internet, and the increasing use of portable computing devices suggest that wireless Internet access will rise rapidly over the next few years Rapid progress in digital and RF technology is making possible highly compact and integrated terminal devices, and the introduction of sophisticated wireless data software is

J. Chuang; N. Sollenberger

2000-01-01

258

Ultra-Wideband Direction Finding Using a Fiber Optic Beamforming Processor.  

National Technical Information Service (NTIS)

This paper describes a wideband electro-optic direction finding (DF) processor employing an array of laser diodes, an array of photodetectors, and a network of fiber optic delay lines. This DF filter offers a potential operational bandwidth in excess of 1...

S. A. Pappert

1988-01-01

259

Filter-free ultra-wideband doublet pulses generation based on wavelength conversion and fiber dispersion effect  

NASA Astrophysics Data System (ADS)

Filter-free ultra-wideband (UWB) doublet pulse generation is experimentally demonstrated in the optical domain based on cross-gain modulation (XGM) in semiconductor optical amplifier (SOA) and UWB-over-fiber technology is implemented by exploiting dispersion-induced pulse broadening effect in single-mode fiber (SMF). In our proposed system, the SOA generates a polarity-inversed Gaussian pulse train with respect to the injected one through the XGM. After a piece of SMF, the bandwidth of polarity-reversed Gaussian pulse broadens due to the induced dispersion. After the combination of the two light waves with a suitable time delay between them, UWB pulse is obtained. The key parameters for UWB pulse, including central frequency, 10 dB bandwidth, as well as fractional bandwidth are experimentally obtained with 8 GHz, 9.9 GHz and 123% respectively. The generated UWB doublet pulse conforms with the UWB definition of Federal Communications Commission (FCC).

Shao, Jing; Sun, Junqiang

2012-06-01

260

Research of all-optical ultra-wideband triplet signal source based on a single semiconductor optical amplifier  

NASA Astrophysics Data System (ADS)

A novel scheme for all-optical ultra-wideband triplet signal pulse generation based on the cross-gain modulation (XGM) in a single semiconductor optical amplifier (SOA) is demonstrated. In this scheme, only one optical source and one SOA are needed, so the configuration is simple. Due to only one wavelength is included in the generated triplet pulse, no time difference between output signal light and probe light is introduced during the transmission process. By using the software of Optisystem 7.0, the impacts of the input signal width, the optical power and the wavelength of the optical source on the generated triplet pulse are numerically simulated and studied. The results show that the proposed scheme has better triplet signal pulse when the input signal pulse width is larger, and it is insensitive to the wavelength change within a certain range.

Xue, Fei; Li, Pei-li; Zheng, Jia-jin; Wang, Li-li; Liang, Wei-kang

2013-07-01

261

A detecting and identifying method for two stationary human targets using single-channel ultra-wideband radar  

NASA Astrophysics Data System (ADS)

A novel technique for single-channel ultra-wideband (UWB) radar to detect and identify two stationary human subjects in different positions is proposed in this article. To detect two stationary human targets accurately and get their life parameters precisely, space-frequency analysis is performed upon the preprocessed data in horizontal dimension and then a non-linear threshold is calculated for automatic identification. Experiments are conducted to evaluate the effectiveness of the proposed technique. In 61 data sets with two stationary human subjects, the accuracy of identification reaches 72%. The experimental results demonstrate the validity of our approach to detect and identify two stationary human subjects using single-channel UWB radar system. This technique may serve as a basis for further studies on a two-dimensional locator for multi-stationary human subjects via multi-channel UWB radar.

Zhang, Yang; Jiao, Teng; Jing, Xijing; Li, Zhao; Li, Sheng; Yu, Xiao; Lv, Hao; Zhang, Zhu; Wang, Jianqi

2012-12-01

262

High speed wireless data access based on combining EDGE with wideband OFDM  

Microsoft Academic Search

The success of cellular services, combined with the increased presence of laptop computers and the rapid growth in the number of Internet users, indicates that wireless data should have a very bright future. Nevertheless, today the number of wireless data subscribers is small, with the most formidable obstacle to user acceptance being the performance limitations of existing services and products.

Justin Chuang; Leonard J. Cimini; Geoffrey Ye Li; B. McNair; N. Sollenberger; Hong Zhao; Lang Lin; M. Suzuki

1999-01-01

263

All-optical ultra-wideband doublet signal source based on the cross-gain modulation in a semiconductor optical amplifier  

NASA Astrophysics Data System (ADS)

We propose a novel scheme to generate the ultra-wideband (UWB) doublet signal pulse based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). In the scheme, only an optical source and an SOA are needed. As there is only one wavelength included in the output doublet signal pulse, no time difference between the upper and down pulses is introduced during the transmission process. By using the software of Optisystem 7.0, the impacts of the optical power, the SOA current, the wavelength and the input signal pulse width on the generated doublet pulse are simulated and tudied numerically. The results show that when the pulse width of the input signal pulse is larger, the output signal pulse is better, and is insensitive to the change of wavelength. In addition, the ultra-wideband positive and negative monocycles can be generated by choosing suitable optical source power and SOA current.

Zhao, Zan-shan; Li, Pei-li; Zheng, Jia-jin; Pan, Ting-ting; Huang, Shi-jie; Luo, You-hong

2012-03-01

264

480-Mbps, BiDirectional, Ultra-Wideband Radio-Over-Fiber Transmission Using a 1308\\/1564-nm Reflective Electro-Absorption Transducer and Commercially Available VCSELs  

Microsoft Academic Search

We describe 480 Mbps, bi-directional ultra-wideband (UWB) radio signal transmission over 1 km of single-mode optical fiber. Key components are a highly linear, reflective electro absorption transducer (EAT) and commercially available 1308-nm and 1564-nm VCSELs with 4.8-GHz bandwidth. Detailed EAT and 1308-nm VCSEL distortion analyses and measurements are presented highlighting the low intermodulation and harmonic distortion necessary for typical -18-dB

Manoj Prasad Thakur; Terence James Quinlan; Carlos Bock; Stuart D. Walker; Mehmet Toycan; Sandra E. M. Dudley; David W. Smith; Anna Borghesani; David Moodie; Moshe Ran; Yossef Ben-Ezra

2009-01-01

265

A fully-integrated linearized CMOS distributed amplifier based on Multi-Tanh principle for radio over fiber and ultra-wideband applications  

Microsoft Academic Search

The design of a linearized fully-integrated CMOS distributed amplifier with broadband distortion cancellation capability for ultra-wideband applications is presented. Measured linearized CMOS DA results showed that by reducing the IMD3 products of the linearized DA improves the IIP3 DA linearity which can lead to 5 dB improvement in the linearized DA C\\/IM3 power ratio. The linearized CMOS DA provides 7

Ziad El-Khatib; Leonard MacEachern; Samy A. Mahmoud

2009-01-01

266

The determination of the ultra-wideband and time-domain behavior of open area test sites using frequency domain measurements and the complex antenna factor concept  

Microsoft Academic Search

The ultra-wideband and time-domain characteristics of representative Open Area Test Sites (OATS) are determined numerically and experimentally. The analysis and measurements are performed in the frequency domain over a very wide bandwidth (several decades) using a set of calculable biconical antenna with known complex antenna factors (CAFs) according to S. Ishigami et al. (1996) and J. McLean et al. (2002).

James McLean; Robert Sutton

2003-01-01

267

A 2.76 mW, 3–10 GHz ultra-wideband LNA using 0.18 µm CMOS technology  

Microsoft Academic Search

A low-power (2.76 mW) common-gate (CG) low- noise amplifier (LNA) for ultra-wideband (UWB) systems using standard 0.18 m CMOS technology is demonstrated. Instead of the traditional single parallel inductor (LS1 only), we propose a new matching network consisting of a series LS1-RS1 in series with a parallel LS2-RS2 to enhance the input matching bandwidth. Flat and high S21 was achieved

Jin-Fa Chang; Yo-Sheng Lin

2011-01-01

268

A Low-Power and low-noise 21?29 GHz ultra-wideband receiver front-end in 0.18 µm CMOS technology  

Microsoft Academic Search

This paper presents the design and analysis of a 21~29 GHz CMOS receiver front-end (RFE) in a standard 0.18 ?m CMOS process for ultra-wideband (UWB) automotive radar systems. The circuit comprises a low-noise amplifier (LNA), a double-balanced Gilbert-cell mixer, and two Marchand baluns. The performance of the mixer was improved with the current- bleeding technique and a parallel resonant inductor

Sheng-Li Huang; Yo-Sheng Lin; Jen-How Lee

2011-01-01

269

Research of deformation of the fine phase structure of ultra wideband radar signals when passing through the system of identical selective filters  

Microsoft Academic Search

There has been found the exact solution to the response of the system of selective filters to a noise-like ultra wideband radar signal. The expressions were found for two forms of the enveloping curves of certain discretes of a pseudorandom sequence with phase-shift keying, i.e. the square and sinus-quadratic ones. In order to get the solutions with the accuracy up

I. D. Zolotaryov; Ya. E. Miller; T. O. Pozharsky

2005-01-01

270

The scope of application of a reciprocity principle in the theory of antennas at radiation and reception of ultra-wideband signals  

Microsoft Academic Search

An antenna for a reception of the signals, which have spatial length much less than physical length of the antenna and the processes occurring in this antenna, are considered. On an example of the elementary antenna-the symmetric vibrator-features of ultra-wideband (UWB) signals reception are shown and dependence of a current's form in loading of the antenna from a positional relationship

A. V. Zaitsev; I. Ya. Immoreev

2004-01-01

271

Robust ultra low power Wireless Sensor platform with embedded over-molded antenna  

Microsoft Academic Search

In this paper a new wireless sensor node intended for use in ultra-low power Wireless Sensor Networks (WSN) is presented. The node uses commercial of-the-shelf radio, microcontroller and a custom developed antenna embedded in the housing. Over-molding with food-compatible material is used to improve the mechanical robustness of the node. The present work is targeted at commercial food cold chain

M. Tanevski; A. Boegli; P.-A. Farine; F. Merli; J.-F. Zurcher; A. Skrivervik

2011-01-01

272

WideMac: a low power and routing friendly MAC protocol for Ultra Wideband sensor networks  

Microsoft Academic Search

This paper introduces WideMac, a novel low power medium access control protocol designed specifically for Ultra Wide Band Impulse Radio transceivers. The UWB-IR channel offers ultra low power transmissions and unmatchable robustness to multiple access interference. WideMac takes advantage of these two key properties by using asynchronous periodic beacon transmissions from each network node, thereby avoiding the need for network-wide

Jérôme Rousselot; Amre El-Hoiydi; Jean-Dominique Decotignie

2008-01-01

273

Uncompressed video transmission in portable devices for wireless video mirroring service  

Microsoft Academic Search

Wireless transmission of uncompressed video guarantees higher quality with lower latency than compressed video transmission. Although current wireless technologies cannot fully cover required data rates of about a few Gb\\/s for full high definition resolution, some wireless technologies such as ultra-wideband (UWB) provide 1 Gb\\/s data rate which is adequate for uncompressed video transmission in portable devices. In this paper,

Sangjae Lee; Young-Ae Jeon; Sangsung Choi; Man Soo Han; Kyoung-Rok Cho

2012-01-01

274

A novel impulse radio network for tactical military wireless communications  

Microsoft Academic Search

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

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

1998-01-01

275

Wimedia-Defined, Ultra-Wideband Radio Transmission over Optical Fibre  

Microsoft Academic Search

We demonstrate combined wireless and optical fibre channel transmission of Wimedia- defined, MB-OFDM, UWB radio by directly modulation of 4.8GHz VCSELs. Range extension to 400m for multi-cell HDTV sharing is achievable with low-cost remote antenna units.

Y. Ben-Ezra; M. Ran; E. Borohovich; A. Leibovich; M. P. Thakur; Roberto Llorente; S. D. Walker

2008-01-01

276

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

277

A VLSI neural monitoring system with ultra-wideband telemetry for awake behaving subjects  

Microsoft Academic Search

Long term monitoring of neuronal activity in awake behaving subjects can provide fundamental information about brain dynamics for both neuroscience and neuroengineering applications. Recent advances in VLSI systems has focused on designing wireless neural recording systems which can be mounted on animals and acquire neural signals in real time. These advances provide an unparalleled opportunity to study phenomenon such as

Elliot Greenwald; Mohsen Mollazadeh; Nitish Thakor; Wei Tang; Eugenio Culurciello

2010-01-01

278

Ultra-Low Power Wireless Technologies for Sensor Networks  

Microsoft Academic Search

Abstract The new field of wireless sensor networks presents many opportunities and just as many challenges. One particularly dicult,aspect of wireless sensing is the implementation of the radio link. To enable energy scavenging, a technique that harvests ambient energy to power the sensor node indefinitely, sub-

Brian P. Otis

2005-01-01

279

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

280

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

2013-08-01

281

Applications of time-frequency and time-scale transforms to ultra-wideband radar transient signal detection  

NASA Astrophysics Data System (ADS)

In this paper we use a non-stationary approach and analyze ultra-wideband (UWB) radar data using time-frequency and time-scale transformations. The time-frequency transformations considered are the Short-Time Fourier Transform (STFT), the Wigner-Ville Distribution (WD), the Instantaneous Power Spectrum (IPS), and the ZAM transform. Two discrete implementations of the Wavelet Transform (DWT) are also investigated: the decimated A- trous algorithm proposed by Holschneider et al, which uses non-orthogonal wavelets; and the Mallat algorithm, which employs orthogonal wavelets. The transients under study are UWB radar returns from a boat (with and without corner reflector) in the presence of sea clutter, multipath, and radio frequency interferences (RFI). Results show that all time-frequency and time-scale transforms clearly detect the transient radar returns corresponding to the boat with a corner reflector. However, as the radar cross section of the target decreases (boat without a corner reflector), results change drastically as the RFI component dominates the signal. Simulations show that the Instantaneous Power Spectrum may be better adapted for localizing the transient among the time-frequency techniques studied. The decimated A-trous algorithm has the best time resolution of the techniques studied as the return appears better localized in the scalogram.

Fargues, Monique P.; Brooks, William A.

1993-11-01

282

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

2011-05-01

283

Fixed point Dual Carrier Modulation performance for wireless USB  

Microsoft Academic Search

Dual Carrier Modulation (DCM) is currently used as the higher data rate modulation scheme for Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the ECMA-368 defined Ultra-Wideband (UWB) radio platform. ECMA-368 has been chosen as the physical radio platform for many systems including Wireless USB (W-USB), Bluetooth 3.0 and Wireless HDMI; hence ECMA-368 is an important issue to consumer electronics and

Runfeng Yang; R. Simon Sherratt

2009-01-01

284

Two-Layered Wireless Sensor Networks for Warehouses and Supermarkets  

Microsoft Academic Search

The rapid development of wireless sensor network and RFID technologies offers a wide range of novel applications and services. In this paper, we present a two-layered wireless network for warehouses and supermarkets to monitor goods storage and sale, and assist for quality management and market analysis. The hierarchical architecture uses IEEE 802.15.4a impulse ultra-wideband radio (IR-UWB) communication protocol between slave

Zhi Zhang; Zhibo Pang; Jun Chen; Qiang Chen; Hannu Tenhunen; Li-Rong Zheng; Xiaolang Yan

2009-01-01

285

Novel wide-slot antenna fed by equiangular spiral for ultra-wideband communications  

Microsoft Academic Search

In this paper, a novel UWB (Ultra-wide Band) antenna is proposed. This design mainly consists of a wide slot square ground plane and a frequency independent feed line-a 0.5 turn equiangular spiral, which are etched on each side of a substrate separately. Additionally, a circular patch connected with the slotted ground is introduced to tune the working bandwidth of this

J.-X. Huang; F.-S. Zhang; Q. Zhang; Y.-F. Xu; Y.-B. Yang; Y.-C. Jiao

2010-01-01

286

Design and Fabrication of an Ultra-Wideband High-Power Zipper Balun and Antenna  

Microsoft Academic Search

We have designed, built and tested a coaxial zipper that can be used at high voltages. This device is designed to convert the signal from a single-ended (unbalanced coaxial) high-voltage output of Ultra-Wideban d sources to a balanced configuration that can be radiated by a TEM horn. A variety of low voltage measurements were performed, including TDR and field measurements.

Everett G. Farr; Gary D. Sower; Lanney M. Atchley; Donald E. Ellibee

287

A wideband wireless neural stimulation platform for high-density microelectrode arrays.  

PubMed

We describe a system that allows researchers to control an implantable neural microstimulator from a PC via a USB 2.0 interface and a novel dual-carrier wireless link, which provides separate data and power transmission. Our wireless stimulator, Interestim-2B (IS-2B), is a modular device capable of generating controlled-current stimulation pulse trains across 32 sites per module with support for a variety of stimulation schemes (biphasic/monophasic, bipolar/monopolar). We have developed software to generate multi-site stimulation commands for the IS-2B based on streaming data from artificial sensory devices such as cameras and microphones. For PC interfacing, we have developed a USB 2.0 microcontroller-based interface. Data is transmitted using frequency-shift keying (FSK) at 6/12 MHz to achieve a data rate of 3 Mb/s via a pair of rectangular coils. Power is generated using a class-E power amplifier operating at 1 MHz and transmitted via a separate pair of spiral planar coils which are oriented perpendicular to the data coils to minimize cross-coupling. We have successfully demonstrated the operation of the system by applying it as a visual prosthesis. Pulse-frequency modulated stimuli are generated in real-time based on a grayscale image from a webcam. These pulses are projected onto an 11x11 LED matrix that represents a 2D microelectrode array. PMID:17946628

Myers, Frank B; Simpson, Jim A; Ghovanloo, Maysam

2006-01-01

288

Comparative Study of Spread Spectrum and Time Modulated Ultra-Wide-Band Communications.  

National Technical Information Service (NTIS)

Ultra-wideband communications have recently received much attention. A number of military and commercial applications of ultra-wideband have been suggested. An ultra-wideband transmitter generates signals of very large bandwidths (in excess of gigahertzs)...

T. F. Wong J. M. Shea Y. Fang M. D. Denny M. Nabritt

2004-01-01

289

A CMOS impulse radio ultra-wideband transceiver for 1Mb\\/s data communications and ±2.5cm range findings  

Microsoft Academic Search

A CMOS impulse radio ultra-wideband (IR-UWB) transceiver is developed in 0.18?m CMOS. It can be used for a 1Mb\\/s data transceiver, as well as a range finder within an error of ±2.5cm. Chip layout area of a transmitter and a receiver is 0.035mm2 and 0.38mm2, respectively. Power dissipation for 1Mb\\/s data communications is 0.7mW for the transmitter and 4.0mW for

Takahide Terada; Shingo Yoshizumi; Yukitoshi Sanada; Tadahiro Kuroda

2005-01-01

290

Ultra-wideband tunable resonator based on varactor-loaded complementary split-ring resonators on a substrate-integrated waveguide for microwave sensor applications.  

PubMed

This paper presents the modeling, design, fabrication, and measurement of an ultra-wideband tunable twoport resonator in which the substrate-integrated waveguide, complementary split-ring resonators (CSRRs), and varactors are embedded on the same planar platform. The tuning of the passband frequency is generated by a simple single dc voltage of 0 to 36 V, which is applied to each varactor on the CSRRs. Different capacitance values and resonant frequencies are produced while a nearly constant absolute bandwidth is maintained. The resonant frequency is varied between 0.83 and 1.58 GHz and has a wide tuning ratio of 90%. PMID:23549526

Sam, Somarith; Lim, Sungjoon

2013-04-01

291

The detection and localization of targets in 2D or 3D scene using ultra-wideband short-pulse through-the-wall radar  

NASA Astrophysics Data System (ADS)

This paper presents the simulations of TWRI (through the wall radar imaging) in 2D and 3D scene and discusses the finite beamwidth processing to reduce the high calculation of the back-projection algorithm. The 2D and 3D scene are reconstructed to display the performance of the TWRI system using analysis, numerical simulations and real data collected from Through-the-Wall Radar (TWR). At the end of this paper, a novel approach is proposed to locate the position of the target accurately using the Ultra-Wideband Short-Pulse (UWB-SP) Radar.

Wu, Shiyou; Huang, Qiong; Meng, Shengwei; Chen, Jie; Fang, Guangyou; Yin, Hejun

2009-10-01

292

Ultra-low power wireless-online-monitoring platform for transmission line in smart grid  

Microsoft Academic Search

With the development of intelligent power grid, an ultra-low power wireless monitoring platform applied on the tower is designed to improve the level of management and operation of transmission lines. Towers operating status and fault conditions could be monitored online by it. As a result of the level of 10mW power dissipation of MSP430 microcontroller and the Wake on Radio

Bojie Sheng; Wenjun Zhou

2010-01-01

293

Ultra-Wide Bandwidth Signal Propagation for Indoor Wireless Communications  

Microsoft Academic Search

An ultra-wide bandwidth (UWB) signal propagation experiment is performed in a typical modern office building in order to characterize the UWB signal propagation channel. The bandwidth of the signal used in this experiment is in excess of one GHz. The robustness of the WVB signal to fades is quantified through histogram and cumulative distribution of the received energy in various

Moe Z. Win; Robert A. Scholtz; Mark A. Barnes

1997-01-01

294

An ultra-wideband tunable multi-wavelength Brillouin fibre laser based on a semiconductor optical amplifier and dispersion compensating fibre in a linear cavity configuration  

NASA Astrophysics Data System (ADS)

A multi-wavelength Brillouin fibre laser (MBFL) with an ultra-wideband tuning range from 1420 nm to 1620 nm is demonstrated. The MBFL uses an ultra-wideband semiconductor optical amplifier (SOA) and a dispersion compensating fibre (DCF) as the linear gain medium and nonlinear gain medium, respectively. The proposed MBFL has a wide tuning range covering the short (S-), conventional (C-) and long (L-) bands with a wavelength spacing of 0.08 nm, making it highly suitable for DWDM system applications. The output power of the observed Brillouin Stokes ranges approximately from —5.94 dBm to —0.41 dBm for the S-band, from —4.34 dBm to 0.02 dBm for the C-band and from —2.19 dBm to 0.39 dBm for the L-band. The spacing between each adjacent wavelengths of all the three bands is about 0.08 nm, which is approximately 10.7 GHz for the frequency domain.

Zulkifli, M. Z.; Ahmad, H.; Hassan, N. A.; Jemangin, M. H.; Harun, S. W.

2011-07-01

295

An ultra-wideband tunable multi-wavelength Brillouin fibre laser based on a semiconductor optical amplifier and dispersion compensating fibre in a linear cavity configuration  

SciTech Connect

A multi-wavelength Brillouin fibre laser (MBFL) with an ultra-wideband tuning range from 1420 nm to 1620 nm is demonstrated. The MBFL uses an ultra-wideband semiconductor optical amplifier (SOA) and a dispersion compensating fibre (DCF) as the linear gain medium and nonlinear gain medium, respectively. The proposed MBFL has a wide tuning range covering the short (S-), conventional (C-) and long (L-) bands with a wavelength spacing of 0.08 nm, making it highly suitable for DWDM system applications. The output power of the observed Brillouin Stokes ranges approximately from -5.94 dBm to -0.41 dBm for the S-band, from -4.34 dBm to 0.02 dBm for the C-band and from -2.19 dBm to 0.39 dBm for the L-band. The spacing between each adjacent wavelengths of all the three bands is about 0.08 nm, which is approximately 10.7 GHz for the frequency domain. (lasers)

Zulkifli, M Z; Ahmad, H; Hassan, N A; Jemangin, M H; Harun, S W

2011-07-31

296

Comparative analysis of Bluetooth 3.0 with UWB and Certified Wireless-USB protocols  

Microsoft Academic Search

This paper presents the results of the comparative analysis of two different protocols that use or could potentially use the Ultra Wideband (UWB) radio technology - Certified Wireless-USB and Bluetooth 3.0 with UWB. Bluetooth 3.0 with UWB is found to have a number of advantages over Certified Wireless-USB. These include lesser overheads, higher throughputs, higher power efficiency, better device association

Abhishek Bit; Martin Orehek; Waqar Zia

2010-01-01

297

Ultra-wideband radar  

Microsoft Academic Search

Here, we present a description of a block scheme, characteristics, specific features of design and results of testing for a prototype of the ultrawideband (UWB) radar, which has been developed by Russian UWB group researchers at Moscow Aviation Institute at \\

I. Immoreev; E. Ziganshin

2004-01-01

298

An architecture for wireless simulation in NS2 applied to impulse-radio ultra-wide band networks  

Microsoft Academic Search

We present an architecture for implementing a wireless phys- ical 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 phys- ical layer implementation of ns-2, in our case a packet is fully received by our

Ruben Merz; Jean-yves Le Boudec; Joerg Widmer

2007-01-01

299

Ultra-wideband 4 × 4 Phased Array Containing Exponentially Tapered Slot Antennas and a True-Time Delay Phase Shifter at UHF  

NASA Astrophysics Data System (ADS)

For angular scanning a true-time array is developed for UHF ultra-wideband (UWB) applications in time and/or frequency domain. It is based on a 4 × 4 array with antipodal exponentially tapered slot antennas (ETSA, Vivaldi) and a 3-bit phase shifter. Distances of antenna elements are designed to be compromise between gain, scanning angle, side/grating lobe levels. The uniform spaced and fed array maximizes the overall gain. After defining the antenna shape, corrugations are introduced to improve antenna matching and gain pattern. Nine equally spaced beam positions for a 90° scanning angle are induced by an optimized 3-bit phase shifter on high permittivity substrate, while 4 bits are usually needed. Parasitic resonances are avoided by using PIN diodes in single pole double throw configuration. All components and the complete array system are simulated and verified in frequency domain with good agreement. Adaptation to UWB pulses is possible.

Schmitz, J.; Jung, M.; Bonney, J.; Caspary, R.; Schüür, J.; Schöbel, J.

300

Method for the Three-Dimensional Imaging of a Moving Target Using an Ultra-Wideband Radar with a Small Number of Antennas  

NASA Astrophysics Data System (ADS)

Ultra wideband (UWB) radar is considered a promising technology to complement existing camera-based surveillance systems because, unlike cameras, it provides excellent range resolution. Many of the UWB radar imaging algorithms are based on large-scale antenna arrays that are not necessarily practical because of their complexity and high cost. To resolve this issue, we previously developed a two-dimensional radar imaging algorithm that estimates unknown target shapes and motion using only three antennas. In this paper, we extend this method to obtain three-dimensional images by estimating three-dimensional motions from the outputs of five antennas. Numerical simulations confirm that the proposed method can estimate accurately the target shape under various conditions.

Sakamoto, Takuya; Matsuki, Yuji; Sato, Toru

301

Anti-interference ultra-wideband system based on spreading and interleaving * * This project was supported by the National “863” High Technology Research Program of China (2005AA123320) and Universities Natural Science Research Project of Jiangsu Province (05KJB510101)  

Microsoft Academic Search

To suppress the interference in the ultra-wideband (AI-UWB) system is a challenging problem. An anti-interference multiband orthogonal frequency-division multiplexing ultra-wideband (AI-UWB) system, based on spreading and interleaving is addressed. It will exploit the frequency diversity across the subcarriers and provide the robustness to narrow-band interference, by spreading the coded bit streams within each sub-band and interleaving across all sub-bands. Simulating

Zhang Shibing; Zhang Lijun

2007-01-01

302

Evaluation of a wideband crossed exponentially tapered slot printed antenna with cavity back for wireless access points  

Microsoft Academic Search

A new wideband antenna for multi WLAN services is presented in this communication. The operating bandwidth extends from 2.4 to 4.8 GHz. The design is based upon an ultrawideband antenna modified by the introduction of a rectangular cavity back that allows having a frequency stable unidirectional radiation pattern. The proposed configuration presents linear polarization with cross polarization level below &amp;#x2212;20dB.

Carla R. Medeiros; Jorge R. Costa; Carlos A. Fernandes

2010-01-01

303

Gigabit UWB video transmission system for wireless video area network  

Microsoft Academic Search

Ultra-wideband (UWB) technology has offered a large application bandwidth which has been reached up to 1 Gb\\/s recently. One of various UWB specifications, medium access control (MAC) and physical layer (PHY) technologies of WiMedia Alliance can also be used for high speed multimedia applications to establish a wireless video area network (WVAN). In this paper, we propose a Gb\\/s UWB

Sangjae Lee; Youngae Jeon; Sangsung Choi; Man Soo Han; Kyoungrok Cho

2011-01-01

304

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.

2005-12-06

305

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%.

Jacobsen, S.; Birkelund, Y.

2010-01-01

306

Integration platform for 72-GHz photodiode-based wireless transmitter  

NASA Astrophysics Data System (ADS)

Microwave photonics can provide superior advantages towards ultra-wideband wireless communications. In this work, we present an integration platform for 72GHz photodiode based wireless transmitter. The placement and positioning of discrete LNA and PA components, the bias-tee design parameters of photodiode, LNA and PA, and the design parameters for low-loss transition from CPW output of amplified electrical signal at the output of PA to E-band WR12 rectangular waveguide have to be carefully determined. We present general design principles of 72GHz photodiode integration platform. Further, we compare different substrates, which have been implemented into the platform, based on numerical results.

Bouhlal, Bouchaib; Lutzmann, Sascha; Palandöken, Merih; Rymanov, Vitaly; Stöhr, Andreas; Tekin, Tolga

2012-02-01

307

UWB Antennas Integration Effects for Wireless Communication Applications  

NASA Astrophysics Data System (ADS)

In this chapter, a return loss measurement campaign was achieved to study the effect of the close environment on antenna's behavior in wireless application scenarios. Five different planar ultra-wideband antennas were measured on different devices (keyboard, screen, Internet box, and two laptops). General similarities in the bandwidth and matching efficiency behaviors were noticed for the antennas when mounted on the same devices in the same positions. In a purpose of modeling, the results can be used to classify the antennas and describe general behaviors on common used devices in wireless applications.

Mellah, M.-A.; Roblin, C.; Sibille, A.

308

A 31.7-GHz high linearity millimeter-wave CMOS LNA using an ultra-wideband input matching technique  

NASA Astrophysics Data System (ADS)

A CMOS low-noise amplifier (LNA) operating at 31.7 GHz with a low input return loss (S11) and high linearity is proposed. The wideband input matching was achieved by employing a simple LC compounded network to generate more than one S11 dip below -10 dB level. The principle of the matching circuit is analyzed and the critical factors with significant effect on the input impedance (Zin) are determined. The relationship between the input impedance and the load configuration is explored in depth, which is seldom concentrated upon previously. In addition, the noise of the input stage is modeled using a cascading matrix instead of conventional noise theory. In this way Zin and the noise figure can be calculated using one uniform formula. The linearity analysis is also performed in this paper. Finally, an LNA was designed for demonstration purposes. The measurement results show that the proposed LNA achieves a maximum power gain of 9.7 dB and an input return loss of < -10 dB from 29 GHz to an elevated frequency limited by the measuring range. The measured input-referred compression point and the third order inter-modulation point are -7.8 and 5.8 dBm, respectively. The LNA is fabricated in a 90-nm RF CMOS process and occupies an area of 755 × 670 ?m2 including pads. The whole circuit dissipates a DC power of 24 mW from one 1.3-V supply.

Geliang, Yang; Zhigong, Wang; Zhiqun, Li; Qin, Li; Zhu, Li; Faen, Liu

2012-12-01

309

Method and system of time-of-arrival estimation for ultra wideband multi-band orthogonal frequency division multiplexing signals  

US Patent & Trademark Office Database

A time-of-arrival (TOA) estimation method for multi-band orthogonal frequency division multiplexing (MB-OFDM) signals uses a simple equally-spaced channel model to recover the impulse response of the wireless channel, and locates the delay of the first channel path by minimizing the energy leakage from the first channel path. The TOA is estimated based on the delay. Such a method does not require channel information for TOA estimation at the receiver and does not require modification of the receiver structure. The method also avoids a sub-optimal solution known to occur in maximum likelihood (ML) estimation.

Xu; Huilin (Gainesville, FL); Chong; Chia-Chin (Santa Clara, CA); Guvenc; Ismail (Santa Clara, CA)

2011-09-20

310

Position Estimation of Access Points in 802.11 Wireless Networks  

SciTech Connect

We developed a technique to locate wireless network nodes using multiple time-of-flight range measurements in a position estimate. When used with communication methods that allow propagation through walls, such as Ultra-Wideband and 802.11, we can locate network nodes in buildings and in caves where GPS is unavailable. This paper details the implementation on an 802.11a network where we demonstrated the ability to locate a network access point to within 20 feet.

Kent, C A; Dowla, F U; Atwal, P K; Lennon, W J

2003-12-05

311

Applying Beamforming to Address Temporal Correlation in Wireless Channel Characterization-Based Secret Key Generation  

Microsoft Academic Search

Wireless secret key generation (WKG) methods based on communications channel characterizations have gained significant interest as a mechanism for providing secure point-to-point communications. Ultra-wide band (UWB) WKG solutions provide an advantage over narrow- and wide-band approaches in that they can generate secure keys even when Alice and Bob, the two communicating parties, and all objects within the environment in which

Masoud Ghoreishi Madiseh; Stephen W. Neville; Michael L. McGuire

2012-01-01

312

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

313

RoF Delivery over PONs of Optically Shaped UWB Signals for Gigabit\\/s Wireless Distribution in the Home  

Microsoft Academic Search

We propose and experimentally demonstrate gen- eration and distribution of optimally power efficient impulse- radio ultra-wideband (IR-UWB) waveforms over passive optical networks (PONs) for high bit rate wireless data distribution in the home. We use a reconfigurable UWB pulse generator in the context of radio over fiber delivery over a PON for fiber to the home\\/premises services. The single mode

Mohammad Abtahi; Leslie A. Rusch

2011-01-01

314

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

315

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.

316

Wideband antenna EIRP measurements for various UWB waveforms  

Microsoft Academic Search

We experimentally investigate pulse shaping in the optical domain of ultra-wideband pulses and RF transmission via a wideband antenna. The effective isotropically radiated power (EIRP) is calculated based on the measured transmit power; the resultant power spectral density (PSD) is compared to the FCC (US Federal Communications Commission) power spectral mask for each of three generated pulse shapes: a Gaussian

Mehrdad Mirshafiei; Mohammad Abtahi; Sophie LaRochelle; Leslie A. Rusch

2008-01-01

317

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

318

Ultra-Low Power Event-Driven Wireless Sensor Node Using Piezoelectric Accelerometer for Health Monitoring  

NASA Astrophysics Data System (ADS)

We describe a low power consumption wireless sensor node designed for monitoring the conditions of animals, especially of chickens. The node detects variations in 24-h behavior patterns by acquiring the number of the movement of an animal whose acceleration exceeds a threshold measured in per unit time. Wireless sensor nodes when operated intermittently are likely to miss necessary data during their sleep mode state and waste the power in the case of acquiring useless data. We design the node worked only when required acceleration is detected using a piezoelectric accelerometer and a comparator for wake-up source of micro controller unit.

Okada, Hironao; Kobayashi, Takeshi; Masuda, Takashi; Itoh, Toshihiro

2009-07-01

319

TBCD-TDM: Novel Ultra-Low Energy Protocol for Implantable Wireless Body Sensor Networks  

Microsoft Academic Search

The field of remote health monitoring now includes technologies such as home and mobile health monitoring, tele-retinal imaging, tele-radiology, remote cardiac monitoring, video conferencing and sensors for remote diagnosis and treatment to patients. In this regard, implantable wireless body sensor networks (IWBSNs) have recently emerged as an important and growing research area. These implantable sensors are required to be reliable,

Fariborz Fereydouni-Forouzandeh; Otmane Aït Mohamed; M. Sawan; F. Awwad

2009-01-01

320

SyncWUF: An Ultra Low-Power MAC Protocol for Wireless Sensor Networks  

Microsoft Academic Search

In wireless sensor networks, power consumption is one of the key design issues because a large number of sensor nodes are powered by cheap batteries. Switching the RF transceiver, which is one of the biggest power consumers in a sensor node, to low-power sleep mode as much as possible has been proven to be a very efficient way to save

Xiaolei Shi; Guido Stromberg

2007-01-01

321

Characterization of ultra-wide bandwidth wireless indoor channels: a communication-theoretic view  

Microsoft Academic Search

An ultra-wide bandwidth (UWB) signal propagation experiment is performed in a typical modern laboratory\\/office building. The bandwidth of the signal used in this experiment is in excess of 1 GHz, which results in a differential path delay resolution of less than a nanosecond, without special processing. Based on the experimental results, a characterization of the propagation channel from a communications

Moe Z. Win; Robert A. Scholtz

2002-01-01

322

Ultra low power wireless ECG system with beat detection and real time impedance measurement  

Microsoft Academic Search

A wireless ECG monitoring system is presented that is able to perform high-quality ECG signal acquisition, beat detection, and real time monitoring of skin-electrode impedance which can be used to monitor the presence of motion artefacts. The whole system consumes only 170?W while performing local beat detection. The beat detection algorithm was verified against the MIT-BIH arrhythmia database and obtains

Tom Torfs; Refet Firat Yazicioglu; Sunyoung Kim; Hyejung Kim; Chris Van Hoof; Dilpreet Buxi; Inaki Romero; Jacqueline Wijsman; Fabien Massé; Julien Penders

2010-01-01

323

Wireless connections within spacecrafts to replace wired interface buses  

NASA Astrophysics Data System (ADS)

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

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

324

Micromachined wide-band lithium-niobate electrooptic Modulators  

Microsoft Academic Search

We present our detailed study of a micromachined substrate approach for a wide-band lithium-niobate modulator and other ultra-wideband RF interconnection applications. Resonant substrate mode coupling often results in large RF loss that affects the frequency performance in LiNbO3 modulators. Using the micromachining approach, we demonstrated significantly reduced resonant mode coupling loss in LiNbO3 modulator electrodes. In this paper, the effects

Yongqiang Shi

2006-01-01

325

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

326

An oil peaking switch to drive a dipole antenna for wideband applications  

Microsoft Academic Search

When the load is an antenna, the High Pulsed Power (HPP) generators allow generating electromagnetic waves in the form of pulses for wideband or ultra wideband applications. In this case, the HPP generator is usually made up of a primary energy source loading a power-amplification system. A Marx generator or a Tesla transformer is classically used as a power- amplifier.

R. Pecquois; L. Pecastaing; M. Rivaletto; A. De Ferron; P. Pignolet; J. Martin; L. Caramelle; J. M. Duband; R. Vezinet

2011-01-01

327

Hardware Implementation of a Genetic Algorithm Based Canonical Singed Digit Multiplierless Fast Fourier Transform Processor for Multiband Orthogonal Frequency Division Multiplexing Ultra Wideband Applications  

Microsoft Academic Search

Problem statement: Ultra Wide Band (UWB) technology has attracted many researchers' attention due to its advantages and its great poten tial for future applications. The physical layer standard of Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM) UWB system is defined by ECMA International. In this standard, th e data sampling rate from the analog-to-digital converter to the physical layer is up

Mahmud Benhamid; Masuri Bin Othman

2009-01-01

328

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

329

2×2 dual linear polarization wideband slot array  

Microsoft Academic Search

A new wideband compact slot antenna array with cavity back for indoor wireless local area network (WLAN) access points (AP) is described, covering several wireless communication services from 2.4 to 4.8 GHz, that is especially designed to enhance multiple-input-multiple- output (MIMO) system performance. Despite very close packing of the array elements, these exhibit very low mutual coupling (<-23 dB) and

J. R. Costa; E. B. Lima; C. R. Medeiros; C. A. Fernandes

2011-01-01

330

Wireless loops: What are they?  

Microsoft Academic Search

Several loop applications of wireless technology are aimed at reducing the cost of deploying communications services ranging\\u000a from telephone to wideband video. In these applications, wireless links replace a portion of a wireline loop from a central\\u000a location (a central office or cable headend) to a subscriber. The replacement of labor-intensive wireline technology by complex\\u000a mass-produced integrated electronics in wireless

Donald C. Cox

1996-01-01

331

MPAP: virtualization architecture for heterogenous wireless APs  

Microsoft Academic Search

This demonstration shows a novel virtualization architecture, called Multi-Purpose Access Point (MPAP), which can virtualize multiple heterogenous wireless standards based on software radio. The basic idea is to deploy a wide-band radio front-end to receive wireless signals from all wireless standards sharing the same spectrum band, and use separate software base-bands to demodulate information stream for each wireless standard. Based

Yong He; Ji Fang; Jiansong Zhang; Haicheng Shen; Kun Tan; Yongguang Zhang

2010-01-01

332

A 0.13-$\\\\mu{\\\\hbox {m}}$ 1GS\\/s CMOS Discrete-Time FFT Processor for Ultra-Wideband OFDM Wireless Receivers  

Microsoft Academic Search

A discrete-time (DT) fast Fourier transform (FFT) processor is presented as an architectural approach to Fourier transform processing multigigahertz of spectral bandwidth. The processor is considered with the specific application of demodu- lating orthogonal frequency-division multiplexing (OFDM) mod- ulation. The processor enables increased receiver linearity beyond that which is typically limited by the signal-to-noise-and-distortion ratio of high sample rate ADCs

Mark Lehne; Sanjay Raman

2011-01-01

333

A new compact wideband balun  

Microsoft Academic Search

A novel wideband balun has been developed for MMIC (monolithic microwave integrated circuit) applications. Simple RF reflection and coupling principles are used to achieve a wideband performance in a simple microstrip configuration. The design was intended for 8- to 18-GHz wideband mixer applications. According to the predicted performance the insertion loss was better than 2 dB from 7 to 19

M. C. Tsai

1993-01-01

334

Ultra-wideband CMOS-MEMS radio  

Microsoft Academic Search

Current ultrawideband (UWB) radios have several unsolved issues in front-end performance including difficult and expensive clock synthesizer designs, and power hungry baseband functions. In fact, the expected breakthrough of the very useful UWB technology has stalled since realized high bitrate integrated radios are much too expensive in the sense that they dissipate a lot of DC power and that their

Esa Tiiliharju; Tero Koivisto; Janne Maunu; N. Chekurovy; I. Tittoneny

2009-01-01

335

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

336

Integration of sensors and RFID's on ultra-low-cost paper-based substrates for wireless sensor networks applications  

Microsoft Academic Search

In this paper, an overview of novel integration approaches for improved performance UHF radio frequency identification (RFID) tags and embedded sensors and batteries is presented. Organic substrates, such as paper, that have been very rarely used in UHF and RF applications in the past and could potentially utilize inkjet printing techniques, are also thoroughly investigated for the realization of ultra-

Antonio Ferrer-Vidal; Amin Rida; Serkan Basat; Li Yang; Manos M. Tentzeris

2006-01-01

337

Robust wideband DOA estimation  

Microsoft Academic Search

Within the last decade there has been a growing interest in developing techniques for the estimation of the direction of arrival (DOA) of wavefronts carrying wideband signals. The coherent signal-subspace method (CSM) is one of the most largely adopted technique and it is based upon the so-called focusing matrices. In the literature, several focusing matrices have been proposed and the

Fabrizio Sellone

2005-01-01

338

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 (Qr = 700 and Qa = 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

339

Ultra-wide-band (UWB) band-pass-filter using integrated passive device (IPD) technology for wireless applications  

Microsoft Academic Search

Recently, the need for high speed data transmission and reception coupled with the ever increasing demand for mobility in consumer devices has generated a great interest in low cost devices with smaller form-factors. In this paper, the design of an ultra-wide-band (UWB) band-pass-filter (BPF) with a pass-band frequency bandwidth from 7.0 GHz to 9.0 GHz (15 dB return loss bandwidth)

Yong-Taek Lee; Kai Liu; Robert Frye; Hyun-Tai Kim; Gwang Kim; Billy Ahn

2009-01-01

340

Photonic wideband array antennas  

Microsoft Academic Search

Presents an introduction to the optical control of array antennas by using fiber optic links for remote control and a photonic time shift network for wide instantaneous bandwidth. An overview of the development of a wideband conformal array designed for airborne surveillance radars is given. The paper covers the system design and the performance of an L-band (850-1400 MHz) M-element

J. J. Lee; R. Y. Loo; S. Livingston; V. I. Jones; J. B. Lewis; Huan-Wun Yen; G. L. Tangonan; M. Wechsberg

1995-01-01

341

Hybrid TDOA\\/AOA mobile user location for wideband CDMA cellular systems  

Microsoft Academic Search

This paper proposes a mobile user location scheme for wideband code-division multiple-access (CDMA) wireless communication systems. To achieve high location accuracy and low cost of the mobile receiver, the location scheme combines the time difference of arrival (TDOA) measurements from the forward link pilot signals with the angle of arrival (AOA) measurement from the reverse link pilot signal. High chip

Li Cong; Weihua Zhuang

2002-01-01

342

Wideband propagation modelling for indoor environments and for radio transmission into buildings  

Microsoft Academic Search

With the introduction of wireless broadband services in indoor environments there is a growing interest in propagation models for the mobile radio channel inside buildings. Because of the increasing transmission rates propagation models should be able to calculate the field strength coverage as well as the wideband properties for these indoor scenarios. This paper presents a new ray optical approach,

R. Hoppe; P. Wertz; G. Wolfle; F. M. Landstorfer

2000-01-01

343

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

344

Wideband modem characterization testing  

NASA Astrophysics Data System (ADS)

As part of an investigation into the causes for random, unexplained data 'dropouts' on a Defense Satellite Communication link between the Air Force Satellite Control Facility, Sunnyvale, California and the Indian Ocean Remote Tracking Station, a number of tests were conducted to characterize the performance parameters of the wideband modems used on the link. These tests were used to measure the loop parameters of the modem Carrier and Timing Recovery Loops and to determine the modem sensitivity to RF phase disturbances, data rate variations and various repetitive bit patterns. This paper describes the test technique used and the results obtained.

Finn, G. T.

345

A CMOS Wideband RF Front-End With Mismatch Calibrated Harmonic Rejection Mixer for Terrestrial Digital TV Tuner Applications  

Microsoft Academic Search

A wideband direct-conversion RF front-end for Advanced Television Systems Committee terrestrial digital TV (DTV) tuner applications is realized in a 0.18-?m CMOS technology. In order to effectively solve the critical local oscillator (LO) harmonic mixing problem in an ultra-wideband frequency environment of 48-860 MHz, the combination of a mismatch calibrated harmonic rejection mixer (HRM) and a simple preceding integrated third-order

Hyouk-Kyu Cha; Kuduck Kwon; Jaeyoung Choi; Hong-Teuk Kim; Kwyro Lee

2010-01-01

346

Wideband impedance transformer for UHF power transistor time domain waveform measurement system  

Microsoft Academic Search

A wideband impedance transformer for an ultra high frequency power transistor periodic time domain waveform measurement system was developed. It matches the low impedance levels of a bipolar power transistor to the standard 50 ohm level at the measurement frequency as well as its harmonics. The determination of the transformer scattering parameters for error correction of the time domain measurement

Kari Lehtinen; Tapio Malmivaara; Markku Sipilae

1989-01-01

347

Wireless Technologies in Support of ISS Experimentation and Operations.  

National Technical Information Service (NTIS)

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&.

P. Fink R. Wagner

2012-01-01

348

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

349

Wideband RELAX and wideband CLEAN for aeroacoustic imaging  

Microsoft Academic Search

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

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

2004-01-01

350

Multiband OFDM-UWB signals over hybrid fiber-wireless Link  

NASA Astrophysics Data System (ADS)

The Orthogonal Frequency Division Multiplexing Ultra-Wideband (OFDM-UWB) technique that widely used for the new emerging networks requires further investigation in terms of fiber length and UWB signal degradation. Simulations are used in this work to estimate the system performance which consists of two main links: wireless and optical, where the channel is considered as point to point between the UWB transmitter and the UWB receiver. In this paper, we demonstrate the use of UWB signals of carrying data to the end users within a campus area through an optical fiber link. A cost effective optical components are used in the system. The UWB signals are transmitted over a channel bandwidth of 528 MHz via low bit rate OFDM-subcarriers. Then, the accumulated data from each OFDM subcarrier is transmitted over an optical channel. Finally, UWB signals are wirelessly distributed to the end user over a short distance depending on the data rate being used. For this point to point system, using simulations, the performance of the system in terms of the bit error rate (BER) is examined. The results show that the wireless channel effects have the larger impact on the overall system performance compared with the fiber length effect.

Kenshil, S.; Rashwan, G.; Matin, M.

2012-10-01

351

Wideband and Extended Wideband Temperature Operation Field Tests in Telephone Central Offices  

Microsoft Academic Search

Field tests involving wideband and extended wideband temperature operation were conducted in several electronic central offices in South Central Bell and Pennsylvania Bell during 1980-1982. Wideband temperature operation is defined as no space heating or cooling between 65 and 80°F with fan operation only when heating or cooling is required, or for ventilation. Extended wideband operation allows a further relaxation

J. R. McKay

1984-01-01

352

Wideband Waveguide Polarizer Development for SETI.  

National Technical Information Service (NTIS)

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

P. Lee P. Stanton

1991-01-01

353

Wide-Band Monolithic Acoustoelectric Memory Correlators.  

National Technical Information Service (NTIS)

Significant applications in radar and communication systems exist for memory correlators. These analog surface acoustic wave (SAW) devices are capable of storing one wide-band signal and then, some time later, correlating with it another wide-band signal....

R. A. Becker R. W. Ralston P. V. Wright

1982-01-01

354

Compatibility Analysis between Wideband Code Division Multiple Access (WCDMA) Service and Global Mobile Personal Communication by Satellite (GMPCS)  

Microsoft Academic Search

Due to explosive demand for wireless service and limited frequency spectrum resource, an efficient use of frequency spectrum has been a critical issue for making a full use of available frequency bands. In this paper, we analyze the compatibility between wideband code division multiple access (WCDMA) and the global mobile personal communication by satellite (GMPCS) which is investigated by analyzing

Yong-il Oh; Chung Sang Lyu; Seong Teak Oh; Jin Young Kim

2008-01-01

355

Ultra-fast Pulse Transmitter for UWB Microwave Radar  

Microsoft Academic Search

A design and measurement result on formation of ultra short pulses for the transmitter of ultra wideband (UWB) microwave radar is presented in this paper. Ultra-fast transmitter pulses were generated by avalanche pulse generator and successively sharpened using step recovery diode (SRD) based pulse sharpener circuit. The SRD diode was auto-biased from the input pulses of amplitude +7V. Present method

A. Ruengwaree; A. Ghose; J. Weide; G. Kompa

2006-01-01

356

Wideband transhorizon channel characterization  

NASA Astrophysics Data System (ADS)

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

Ndzi, David; Austin, John; Vilar, Enric

2001-09-01

357

Performance evaluation of TCP\\/RLP protocol stack over CDMA wireless link  

Microsoft Academic Search

Due to the high frame error rate in wireless communication channels, an additional link layer protocol, Radio Link Protocol (RLP), has been introduced in the newly approvedData Services Option Standard for Wideband Spread Spectrum Digital Cellular System. In this paper, we investigate performance issues of a typical Cod Division Multiple Access (CDMA) wireless link using the protocol stack given in

Gang Bao

1996-01-01

358

Evolutionary games in wireless networks.  

PubMed

We consider a noncooperative interaction among a large population of mobiles that interfere with each other through many local interactions. The first objective of this paper is to extend the evolutionary game framework to allow an arbitrary number of mobiles that are involved in a local interaction. We allow for interactions between mobiles that are not necessarily reciprocal. We study 1) multiple-access control in a slotted Aloha-based wireless network and 2) power control in wideband code-division multiple-access wireless networks. We define and characterize the equilibrium (called evolutionarily stable strategy) for these games and study the influence of wireless channels and pricing on the evolution of dynamics and the equilibrium. PMID:19963703

Tembine, Hamidou; Altman, Eitan; El-Azouzi, Rachid; Hayel, Yezekael

2009-12-04

359

Wideband channel modeling for line-of-sight microcellular environment with low base station antenna height  

Microsoft Academic Search

In high-speed wireless data transmission, the most significant problem is severe frequency-selective fading. Consequently, obtaining information on the propagation delay is very important and precise modeling of a radio channel is essential in designing mobile multimedia communications systems. Empirical wideband channel models with a low base station antenna are proposed for the line-of-sight microcellular environment. The models determine the delay

Kazunnasa TAIRA; Shinya SEKIZAWA; Yoshihiro HASE

1998-01-01

360

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; Buehrer, Richard

2009-10-09

361

Polarimetric wideband holography using microwaves  

Microsoft Academic Search

A fully polarimetric, electromagnetic inversion formulation of the inverse diffraction problem is presented. It is shown how scattering field data can be used in this formulation to determine the geometry and induced flows of the scattering object. The application of the formulation to polarimetric wideband holography using microwaves is demonstrated.

K. J. Langenberg; M. Brandfass; P. Fellinger; T. Gurke; T. Kreutter

1991-01-01

362

Optically Beamformed Wideband Array Performance  

Microsoft Academic Search

Optical beamforming networks (OBFNs) are an interesting alternative for the design of wideband antenna arrays, mainly due to their low losses and weight, their high parallel processing capabilities and their electromagnetic immunity. Nevertheless, for a practical implementation, different technological and architectural tradeoffs need to be assessed. In this paper, the performance of an OBFN system is analytically studied and experimentally

Lluís Jofre; Chrysavgi Stoltidou; Sebastián Blanch; Teresa Mengual; Borja Vidal; Javier Marti; Iain McKenzie; J. M. del Cura

2008-01-01

363

Adaptive wideband aeroacoustic array processing  

Microsoft Academic Search

Incoherent and coherent wideband array processing techniques for aeroacoustic detection and tracking of ground vehicles are contrasted. Experimental results for a circular array are presented, illustrating complexity and performance tradeoffs. Incoherent and coherent MUSIC are used for comparison. Complexity is dominated in both cases by singular value decomposition (SVD) calculation performed M times for the incoherent case and S times

Tien Pham; Brian M. Sadler

1996-01-01

364

Wideband Optical TTD SAR Antenna  

Microsoft Academic Search

Optical beam forming networks (OBFN) are an interesting alternative for the design of wideband antenna arrays. They are potentially more power efficient and lighter than their microwave counterparts. These two characteristics make them especially appealing in space remote sensing applications. However, in a practical implementation of OBFN in a real SAR system, different architectural and technological tradeoffs need to be

F. Dalmases; S. Blanch; J. Romeu; L. Jofre; B. Vidal; J. Marti; I. McKenzie; E. Vez; J. Santamaria

2006-01-01

365

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.

Choliz, Juan; Hernandez, Angela; Valdovinos, Antonio

2011-01-01

366

Realistic modeling of the biological channel for the design of implantable wireless UWB communication systems.  

PubMed

Several emerging medical applications require that a miniature data acquisition device be implanted into the head to extract and wirelessly communicate brain activity to other devices. Designing a reliable communication link for such an application requires a realistic model of the surrounding biological tissues. This paper exploits a realistic model of the biological channel to design a suitable wireless ultra wideband communication link in a brain monitoring application. Two scenarios for positioning the implanted transmitting antenna are considered. The 1(st) scenario places the antenna under the skull, whereas the 2(nd) scenario places the antenna under the skin, above the skull. The propagation characteristics of the signal through the tissues of the human head have been determined with full-wave electromagnetic simulation based on Finite Element Method. The implantable antenna and the external antenna are key components to establish an electromagnetic link between an implanted transmitter and an external receiver. The average specific absorption rate (ASAR) of the implantable antennas are evaluated and compared for the two proposed scenarios. Moreover, the maximum available power from the implanted antenna is evaluated to characterize the performance of the communication link established between the implantable antenna and the external antenna, with respect to spectrum and safety regulations. We show how sensitive the receiver must be in order to implement a reliable telemetry link based on the proposed model of the channel. PMID:23367300

Bahrami, Hadi; Gosselin, Benoit; Rusch, Leslie A

2012-01-01

367

Terahertz wireless communication link at 300 GHz  

Microsoft Academic Search

We present a terahertz wave wireless link operating at 300 GHz which has a potential for use in ultra fast future wireless services in short range. Terahertz wave was generated and modulated with photonic technologies in the transmitter, allowing us to use radio on fiber system concept as well. For the receiver, we used a Schottky barrier diode detector integrated

Ho-Jin Song; Katsuhiro Ajito; Atsushi Wakatsuki; Yoshifumi Muramoto; Naoya Kukutsu; Yuichi Kado; Tadao Nagatsuma

2010-01-01

368

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

369

A Novel Ka-band Wideband Slot Antenna for System-on-Package Application  

Microsoft Academic Search

An novel wideband Ka-band substrate integrated waveguide (SIW) slot antenna is proposed in this paper. The antenna has an ultra-low profile (only about 2.5% of the operating wavelength). Slot and cavity resonators are introduced simultaneously to extend impedance bandwidth. The result demonstrates that the antenna can operate in 30.25–33.16 GHz (about 9% of the fractional bandwidth). Unlike the traditional slot

J. Z. Peng; S.-Q. Xiao; X.-J. Tang; J. C. Lu

2008-01-01

370

A modular wideband sound absorber  

NASA Astrophysics Data System (ADS)

The absorption coefficients were measured of various depths of RW2 grade Rockwool laid directly on the floor of the ISO-Standard reverberation room at BBC Research Department. The Rockwool was very effective as a wideband sound absorber. A new absorber was designed and tested, having the dimensions of the existing BBC type A modular absorbers and containing RW2 Rockwool. The new absorber has a smoother absorption coefficient curve, a less complicated construction, and weighs less than the existing BBC wideband absorber (type A8/A9). It has been named type A11 and has an equivalent performance to that of BBC type A2 and A3 absorbers combined. It complements, very well, the performance of the A10 very low frequency absorber, described in a companion Report (BBC RD No. 1992/10).

Plumb, G. D.

371

Wideband filters employing multilayer gratings  

Microsoft Academic Search

Multilayer surfaces, consisting of stacked inductive and capacitive strips or grids, have been used to design wideband filters in the 5-40 GHz range, with rapid transitions between reflection and transmission. For singly polarized applications, transmission bandwidths of 70-100 percent and edge transition ratios of 1.1-1.3 are realizable at 45 TM incidence using 4-8 layers of capacitive and inductive strips. Factors

P. W. B. Au; E. A. Parker; R. J. Langley

1993-01-01

372

A wideband magnetic energy harvester  

NASA Astrophysics Data System (ADS)

A wideband magnetic energy harvester is proposed by using a number of multiferroic composite fibers of different lengths which are connected in parallel or series. The structural theory is employed to characterize the magnetoelectroelastic behavior of the fibers. A global circuit analysis is then performed. It is shown that such a structure of energy harvester is capable of collecting the ambient magnetic energy over a wide frequency range.

Zhang, C. L.; Chen, W. Q.

2010-03-01

373

Wideband rectenna for energy recycling  

Microsoft Academic Search

This paper presents a new rectenna-element based on aperture coupled microstrip dipole and wide-band band-pass pre-filter inserted between the antenna and the rectifying diode(s). The pre filter is designed to be transparent for all input frequencies in the band of interest and highly attenuating for both DC and higher harmonics. Being repeatedly reflected at the filter output and the output

Adilena Slavova; A. S. Omar

2003-01-01

374

Wideband Modem Design Using FPGAs  

Microsoft Academic Search

1. ABSTRACT New,waveform ,requirements ,are pushing ,the limits of traditional modem design techniques. Fortunately, modern Digital-to-Analog Converter (DAC) and Analog-to-Digital Converter (ADC) can achieve sampling ,rates in the GHz range. These new ,DACs and ADCs allow designers to directly synthesize channels that have bandwidths,of more than 500 MHz+; allowing either wideband,or multi-channel modems,to be ,implemented ,entirely in the digital domain.

Rob Pelt

2004-01-01

375

Wideband acoustic immittance: tympanometric measures.  

PubMed

Wideband tympanometry (WT) measurements provide a view of the acoustic response properties of the middle ear over a broad range of frequencies and ear-canal pressures. These measurements show sensitivity to trends in ear-canal/middle ear maturation and changes in middle ear status as a result of different types of dysfunction. While results from early WT work showed improvements over ambient wideband tests in terms of test performance for identifying middle ear dysfunction and conductive hearing loss (CHL), more recent studies have shown high, but similar test performance for both ambient and tympanometric wideband tests. Case study and group results presented in this article, demonstrating the sensitivity of WT to middle ear dysfunction, CHL, and maturational changes in the middle ear, are promising and suggest the need for additional investigations in individual subjects and large subject populations. Future research should focus on identifying key predictors of developmental trends, middle ear dysfunction, and CHL in an effort to develop middle ear tests with high sensitivity and specificity. Technological advances, more accessibility to equipment, and evolving data analysis techniques should encourage progress in the areas of WT research and clinical application. PMID:23900184

Sanford, Chris A; Hunter, Lisa L; Feeney, M Patrick; Nakajima, Hideko Heidi

2013-07-01

376

Wireless Links  

Microsoft Academic Search

This article discusses the problems that arise when standard Internet protocols such as TCP are used over wireless links. We review wireless link characteristics with case studies drawn from commercial Wireless LANs and Cellular Telephony systems. We discuss problems with Internet protocols when em- ployed over these systems, such as degraded TCP performance when wireless errors are interpreted as congestion

George Xylomenos; George C. Polyzos

377

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

378

Wideband Chirp-Transform Adaptive Filter.  

National Technical Information Service (NTIS)

A wideband chirp-transform adaptive-filter system is described that is capable of providing both spectral monitoring and the excision of multiple narrowband signals. The 80-MHz-bandwidth system processes a wideband continuous 300-MHz center-frequency inpu...

D. R. Arsenault

1985-01-01

379

Minimum sidelobe weights for wideband planar arrays  

Microsoft Academic Search

This paper presented the wideband method that can efficiently compute weights that minimize the SLL over a wide frequency band. This method is valid for an arbitrary broadside planar array and for an arbitrary beamwidth. There may be a significant rise in the overall SLL when extending the array to the wideband case.

Peter J. Bevelacqua; Constantine A. Balanis

2008-01-01

380

Continued Performance of the Wideband Satellite Experiment.  

National Technical Information Service (NTIS)

This report summarizes the work completed during the active data-taking phase of the Wideband Satellite Program. The report includes a complete description of the Wideband satellite data base and a summary of the accomplishments of the program in the area...

C. L. Rino R. C. Livingston B. C. Foir M. D. Cousins

1981-01-01

381

A wideband EMP test system  

SciTech Connect

A wideband EMP tester consisting of a high voltage modulator, transmission line, high voltage peaking switch, and a TEM test cell has been developed that delivers repetitive high frequency EMP pulses to an RF-sealed double-test volume of about 1 ft.{sup 3}. The pulse shape is rectangular, has a duration of 4 ns and a risetime of 120 ps. The system can be operated at pulse repetition rates up to 1500 Hz and electric field levels up to 125 kV/m. Both voltage and pulse rate are continuously adjustable over these ranges may be operated in any combination.

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

1994-07-01

382

A PPM Gaussian monocycle transmitter for ultra-wideband communications  

Microsoft Academic Search

A Gaussian pulse generator incorporating a pulse position modulator for use in an impulse radio ultrawideband system is described. The pulse generator is preceded by a programmable pulse position modulator and comprises a cascade of complex first-order systems, which, in turn, are made up of differential pairs employing partial positive feedback. The resulting PPM Gaussian pulse generator is designed in

S. Baggat; Woiiter A. Serdijn; John R. Long

2004-01-01

383

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

384

Location and Navigation with Ultra-Wideband Signals.  

National Technical Information Service (NTIS)

Existing positioning and navigation applications mainly rely on GNSS. However, its application to indoor, metropolitan and heavy-foliage scenarios is significantly constrained by the satellite visibility, limited accuracy and the intensively frequency-sel...

J. Harris L. Yang

2012-01-01

385

Challenges for ultra-wideband (UWB) CMOS integration  

Microsoft Academic Search

Various methods of utilizing the UWB spectrum have been developed to date, characterized by specific modulation schemes, such as pulse position, pulse amplitude or bi-phase modulation. A new method emerging today utilizes a multi-band approach, where information is encoded in multiple RF subbands at staggered time, each occupying 500MHz bandwidth. A description of multi-band modulation schemes for UWB is included

G. Roberto Aiello

2003-01-01

386

Reconnaissance with ultra wideband UHF synthetic aperture radar  

Microsoft Academic Search

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

MEHRDAD SOUMEKH

1995-01-01

387

Impulse transmitting photonic antenna for ultra-wideband applications  

Microsoft Academic Search

This paper presents a new transmitting photonic antenna based on pigtailed fiber-optic photodiode module integrated with bow-tie radiator for UWB pulse generation using a gain-switched laser diode module.

A. Chizh; S. Malyshev; S. Jefremov; B. Levitas; I. Naidionova

2010-01-01

388

Study on Satellite Communications using Ultra Wideband (UWB) Signals  

Microsoft Academic Search

In this paper, the possibility of satellite communication systems using a multiband UWB signal format is considered. For terrestrial short-distance high-speed communications, multiband UWB schemes are proposed in IEEE 802.15 TG3a and the discussion is ongoing at the standardization body. In the multiband UWB scheme, frequency hopping is adopted over 3.1 - 10.6 GHz, which is regulated by the FCC

Yoshio KUNISAWA Hiroyasu ISHIKAWA; Hisato IWAI; Hideyuki SHINONAGA

389

Dielectric ultra wideband optical E-field sensors  

NASA Astrophysics Data System (ADS)

Aimed at test and evaluation needs on high power microwave (HPM) weapons, we describe new developments on miniature all-dielectric optical field sensors with flat RF sensing response from ~ MHz to 12 GHz, with negligible field perturbation, good sensitivity (~70 mV/(mH?z), and >100dB dynamic range. Present devices use a 20 mm long sensing region in an integrated optical (IO) waveguide Mach-Zehnder interferometer (MZI) using electrooptic (EO) polymer for the waveguide. The fiber-coupled optical transmitter/receiver utilizes common optical communication technology. The incident HPM RF field induces an instantaneous change in the index of refractive of the polymer that is converted into an optical intensity modulation in the MZI device. The poled EO polymer requires no electrodes nor metallic antennas that can distort the field under test. We characterized the frequency response and polarization sensitivity of the field sensor, and both agree well with modeling predictions. Common fabrication limitations result in devices with sensitivity to thermal drift. New sensor designs are being developed with remote bias control that also can provide self-calibration. To further reduce the sensor size and insertion loss, beneficial for array applications, an "in-fiber" field sensor is being developed. The core of a D-shaped fiber is partially removed and replaced with EO polymer. Such a device may use polarization modulation sensing, or be configured in similar MZI structures as the IO waveguide sensors.

Wang, Wen; Lotem, Haim; Zang, De Yu; Forber, Richard; Schultz, Stephen; Selfridge, Richard

2006-06-01

390

Cognitive Technology for Ultra-Wideband\\/WiMax Coexistence  

Microsoft Academic Search

Cognitive radios have been advanced as a technology for the opportunistic use of under-utilized spectrum wherein secondary devices sense the presence of the primary user and use the spectrum only if it is deemed empty. The distinguishing aspect of cognitive radios is the ability to sense the primary user and modify their transmission parameters to avoid interference to the primary.

Shridhar Mubaraq Mishra; S. ten Brink; R. Mahadevappa; R. W. Brodersen

2007-01-01

391

Dielectric ultra wideband optical E-field sensors  

Microsoft Academic Search

Aimed at test and evaluation needs on high power microwave (HPM) weapons, we describe new developments on miniature all-dielectric optical field sensors with flat RF sensing response from ~ MHz to 12 GHz, with negligible field perturbation, good sensitivity (~70 mV\\/(mH&surd;z), and >100dB dynamic range. Present devices use a 20 mm long sensing region in an integrated optical (IO) waveguide

Wen Wang; Haim Lotem; De Yu Zang; Richard Forber; Stephen Schultz; Richard Selfridge

2006-01-01

392

Secret Key Extraction in Ultra Wideband Channels for Unsynchronized Radios  

Microsoft Academic Search

Secure communicationsin UWB based on cryptographic keys generated from channel measurements without a trusted third party have been developed. The fine time res- olution of UWB allows high levels of mutual information to be obtained by a given A and B through independent char- acterizations of their shared communication channel. This mutual informationdetermines the maximum secret key rate available to

Masoud Ghoreishi Madiseh; Michael L. Mcguire; Stephen W. Neville; Ali Asghar Beheshti Shirazi

2008-01-01

393

Entwined spirals for ultra compact wideband frequency selective surfaces  

Microsoft Academic Search

The application of a suitable intertwining scheme to planar periodic quadrifilar spiral frequency selective surfaces (FSSs) is shown to dramatically decrease operating frequencies while greatly expanding the bandwidth. At both normal and oblique incidence the proposed intertwined spiral FSSs provide a very sub-wavelength response at wavelengths 40 times larger than the unit cell size. The high packing density of the

Andrea Vallecchi; Alex G. Schuchinsky

2010-01-01

394

Algorithms for Indoor Positioning Systems Using Ultra-Wideband Signals  

Microsoft Academic Search

Positioning systems and techniques have attracted more and more attention in recent years, in particular with satellite navigation technology as a tremendous enabler, and developments in indoor navigation. The work presented in this thesis has been conducted within the research project: \\\\HERE: indoor positioning based on UWB radio signals\\

J. Yan

2010-01-01

395

Joint Timing and Channel Estimation for Ultra-Wideband Signals  

NASA Astrophysics Data System (ADS)

This paper is concerned with timing synchronization of high rates UWB signals operating in a dense multipath environment, where access must tackle inter-frame interference (IFI), inter-symbol interference (ISI) and even multi-user interference (MUI). A training-based joint timing and channel estimation scheme is proposed, which is resilient to IFI, ISI, MUI and pulse distortion. A low-complexity detection scheme similar to transmit-reference (TR) scheme comes out as a by-product. For saving the training symbols, we further develop an extended decision-directed (DD) scheme. A lower bound on the probability of correct detection is derived which agrees well with the simulated result for moderate to high SNR values. The results show that the proposed algorithm achieves a significant performance gain in terms of mean square error and bit error rate in comparison to the “timing with dirty templates” (TDT) algorithms.

Liu, Tao; Zhu, Shihua

396

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

397

75 FR 62476 - Ultra-Wideband Transmission Systems  

Federal Register 2010, 2011, 2012, 2013

...procedure for swept frequency transmissions was not waived. Thus, the Commission's determination does not constitute ``evisceration'' of the rules. 15. It is a well-established principle that the Commission will waive its rules in specific cases...

2010-10-12

398

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

Microsoft Academic Search

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

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

2010-01-01

399

An advanced 3D ray launching method for wireless propagation prediction  

Microsoft Academic Search

For radio propagation prediction, recent simulations involving ray tracing offer unprecedented accuracy. These techniques surpass statistical channel models and provide a bounty of additional information including RMS delay spread, angle of arrival, and overall wideband channel impulse response. In particular, three dimensional ray tracing produces an accurate, deterministic channel model for wireless system design. This paper presents a new 3D

Greg Durgin; Neal Patwari; Theodore S. Rappaport

1997-01-01

400

Characteristics of wideband ring loop antenna for digital terrestrial broadcasting  

Microsoft Academic Search

In the transmitting and receiving antenna for the UHF band broadcasting, the requirements of the antenna are wideband linear polarization characteristics. It is possible to make a wideband antenna using the loop antenna, arranged vertically, with a circumference length about one wavelength. Miniaturization becomes possible in a simple shape by the realization of a wideband and high-gain linearly polarized ring

H. Kawakami; T. Haga; S. Kon

2005-01-01

401

WALTER : Wireless alliances for testing experiment and research  

Microsoft Academic Search

Ultra and Very high speed radio platforms are key developing technologies for emerging applications but raise issues of efficient radio spectrum management, wireless coexistence and interoperability, from the radio physical layers to the media access control layers. Among these broadband radio platforms, Ultra Wide Band (UWB) is a very promising technology for the broadband transmission of data using spectrum-efficient and

F. Le Gall; P. Cousin; A. Dearlove; M. Garcia; C. Simpson; D. Fuehrer; G. Baldini; A. Langer; X. Chen

2008-01-01

402

Wideband envelope elimination and restoration power amplifier with high efficiency wideband envelope amplifier for WLAN 802.11g applications  

Microsoft Academic Search

This paper presents the design of a silicon bipolar Class-E wideband envelope elimination and restoration (WBEER) power amplifier with a wideband high efficiency envelope amplifier. The envelope amplifier is composed of a linear op-amp stage and a switch buck converter, which achieves high fidelity and high efficiency amplification of wideband high peak to average (PAR) envelope signals. Experimental results show

Feipeng Wang; Donald Kimball; Jeremy Popp; Annie Yang; Donald Y. C. Lie; Peter Asbeck; Lawrence Larson

2005-01-01

403

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

404

Wireless Technology  

NSDL National Science Digital Library

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

2011-01-03

405

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.

406

A UHF wide-band SAR antenna  

Microsoft Academic Search

This UHF wideband antenna was developed for DARPA's synthetic aperture radar (SAR) applications. The small array could be mounted at the belly of an aircraft. The operating frequency covers a 4:1 bandwidth. The antenna including the feed and a contoured ground plane was designed to fit in a shallow radome (50 cm×100 cm×100 cm). The depth of the radome is

J. J. Lee; S. Livingston; G. Sauer; G. Crandall

2000-01-01

407

Wideband Planar Log-Periodic Antenna  

Microsoft Academic Search

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

M. M. Tajdini; M. Shahabadi

2007-01-01

408

Wideband Slot Antenna for WLAN Access Points  

Microsoft Academic Search

This letter presents a new printed slot antenna with cavity back for WLAN Access Points (Base Stations) providing wideband operation bandwidth at least from 2.5 to 4.8 GHz. The design is based upon an ultrawideband antenna configuration modified with the inclusion of a cavity back in order to produce stable unidirectional radiation pattern. The new configuration also ensures a stable

Carla R. Medeiros; Jorge R. Costa; Carlos A. Fernandes

2010-01-01

409

Matched array processing for wideband passive sonar  

Microsoft Academic Search

The Matched Array Processor (MAP) is quadratic adaptive matrix filter designed to optimize detection and bearing estimation of a desired wideband target signature in the presence of interferences. It is made adaptive in the spatial domain to remove interferences entering through the beam sidelobes and it is spectrally matched to the signal of interest. In this paper, MAP performance is

M. Stark

1981-01-01

410

Reconfigurable Wideband Ground Receiver Field Testing  

NASA Astrophysics Data System (ADS)

The Reconfigurable Wideband Ground Receiver (RWGR) system is a variable-data-rate, reprogrammable hardware/software receiver developed to meet the wide range of telemetry demodulation processing needs of the Deep Space Network (DSN). In this article, we report results from a number of field tests with the RWGR deployed to the Deep Space Station 13 (DSS-13) experimental ground station.

Lay, N.; Argueta, A.; Tkacenko, A.; Srinivasan, M.; Andrews, K.

2012-11-01

411

Wideband thin resistive metamaterial radar absorbing screen  

Microsoft Academic Search

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

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

2009-01-01

412

Design of a wideband radar absorbing structure  

Microsoft Academic Search

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

Egemen Yildirim; Ozlem Aydin Civi

2011-01-01

413

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

414

Real-time wideband holographic surveillance system  

Microsoft Academic Search

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

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

1996-01-01

415

Printed Antenna Elements with Attested Ultra Wide Band Array Applicability  

Microsoft Academic Search

Ultra-wideband (UWB) is a radio technology that can be used at very low energy levels, for short-range high-bandwidth communications, by using a large radio spectrum. Due to its high speed rate, this technology is nowadays one of the most promising solutions for communications. Maximum data that can be transmitted per second over a communication channel can be high since the

F. M. Tanyer-Ti?rek

2010-01-01

416

Miniaturization of base station antennas by using adaptive antenna technique for indoor high-speed wireless communication systems  

Microsoft Academic Search

Suppressing multiple reflected waves in an indoor propagation environment is now in great demand because multiple reflected waves significantly degrade the transmission quality of wide-band wireless communication systems. This paper clarifies that adaptive arrays with M+1 elements can completely suppress the multipath waves whose delay times are up to M times greater than the inverse of the signal transmission speed

Yasushi TAKATORI; Kazuhiro UEHARA; Kenichi KAGOSHIMA

1998-01-01

417

Wireless Communication  

NSDL National Science Digital Library

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

Van Zeghbroeck, Bart J.

2012-08-08

418

Terahertz wireless communications based on photonics technologies.  

PubMed

There has been an increasing interest in the application of terahertz (THz) waves to broadband wireless communications. In particular, use of frequencies above 275 GHz is one of the strong concerns among radio scientists and engineers, because these frequency bands have not yet been allocated at specific active services, and there is a possibility to employ extremely large bandwidths for ultra-broadband wireless communications. Introduction of photonics technologies for signal generation, modulation and detection is effective not only to enhance the bandwidth and/or the data rate, but also to combine fiber-optic (wired) and wireless networks. This paper reviews recent progress in THz wireless communications using telecom-based photonics technologies towards 100 Gbit/s. PMID:24104286

Nagatsuma, Tadao; Horiguchi, Shogo; Minamikata, Yusuke; Yoshimizu, Yasuyuki; Hisatake, Shintaro; Kuwano, Shigeru; Yoshimoto, Naoto; Terada, Jun; Takahashi, Hiroyuki

2013-10-01

419

Wireless Communications  

NSDL National Science Digital Library

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

Leske, Cavin.

2002-01-01

420

Wideband high frequency (HF) skywave channel parameters from narrowband measurements  

NASA Astrophysics Data System (ADS)

The HF wideband channel allow the use of spread-spectrum techniques to provide covert communications with low probability of intercept (LPI) and antijam protection. The objective of this work is to determine the extent to which oblique narrowband channel measurements can be used to infer effects in the wideband skywave channel. If oblique narrowband channel measurements can be used as a basis for developing wideband channel models, a large number of existing narrowband measurements can be made available for this task.

Hausman, Cynthia L.; Uffelman, Donald R.; Walton, Thomas L.

421

Electromagnetic Field Measurement in Presence of Radiofrequency Wideband Digital Signals  

Microsoft Academic Search

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

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

422

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

423

A wideband dc-coupled amplifier  

NASA Astrophysics Data System (ADS)

A method is described whereby an ac-coupled high-frequency amplifier and a dc-coupled low-frequency amplifier are connected in parallel in order to obtain a dc-coupled wideband amplifier. By using an operational amplifier which compares the output voltage with the input voltage, the low-frequency amplifier contributes to the overall gain only when the gain of the ac-coupled amplifier droops at low frequencies. Thus, no frequency splitting networks are necessary and the excellent low-frequency features of an operational amplifier are added to those of the ac-coupled wideband amplifier. As an example, a low noise amplifier is described which exhibits a hundredfold gain, a bandwidth from dc to 550MHz, an input bias current of less than 1nA, and an output voltage range of +/-1V.

Janata, E.

2003-03-01

424

WIDEBAND STAR-SHAPED MICROSTRIP PATCH ANTENNA  

Microsoft Academic Search

Abstract—A new wideband and small size star shaped patch antenna fed capacitively by a small diamond,shape patch is proposed.To enhance the impedance bandwidth, posts are incorporated under the patch antenna.HFSS high frequency simulator is employed to analyze the proposed antenna and simulated results on the return loss, the E- and H-plane radiation patterns and Gain of the proposed antenna are

M. Abbaspour; Hamid Reza Hassani

2008-01-01

425

Adaptive OFDM for wideband radio channels  

Microsoft Academic Search

An OFDM (orthogonal frequency division multiplexing) transmission system is simulated with time-variant transfer functions measured with a wideband channel sounder. The individual subcarriers are modulated with fixed and adaptive signal alphabets. Furthermore, a frequency-independent as well as the optimum power distribution are used. The simulations show that with adaptive OFDM, the required signal power for an error probability of 10-3

Andreas Czylwik

1996-01-01

426

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

427

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

428

A wideband dc-coupled amplifier  

Microsoft Academic Search

A method is described whereby an ac-coupled high-frequency amplifier and a dc-coupled low-frequency amplifier are connected in parallel in order to obtain a dc-coupled wideband amplifier. By using an operational amplifier which compares the output voltage with the input voltage, the low-frequency amplifier contributes to the overall gain only when the gain of the ac-coupled amplifier droops at low frequencies.

E. Janata

2003-01-01

429

A wideband vibration-based energy harvester  

Microsoft Academic Search

We present a new architecture for wideband vibration-based micro-power generators (MPGs). It replaces a linear oscillator with a piecewise-linear oscillator as the energy harvesting element of the MPG. A prototype of an electromagnetic MPG designed accordingly is analyzed analytically, numerically and experimentally. We find that the new architecture increases the bandwidth of the MPG during a frequency up-sweep, while maintaining

M S M Soliman; E M Abdel-Rahman; E F El-Saadany; R R Mansour

2008-01-01

430

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

2006-06-01

431

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

432

A wideband RF amplifier for satellite tuners  

NASA Astrophysics Data System (ADS)

This paper presents the design and measured performance of a wideband amplifier for a direct conversion satellite tuner. It is composed of a wideband low noise amplifier (LNA) and a two-stage RF variable gain amplifier (VGA) with linear gain in dB and temperature compensation schemes. To meet the system linearity requirement, an improved distortion compensation technique and a bypass mode are applied on the LNA to deal with the large input signal. Wideband matching is achieved by resistive feedback and an off-chip LC-ladder matching network. A large gain control range (over 80 dB) is achieved by the VGA with process voltage and temperature compensation and dB linearization. In total, the amplifier consumes up to 26 mA current from a 3.3 V power supply. It is fabricated in a 0.35-?m SiGe BiCMOS technology and occupies a silicon area of 0.25 mm2.

Xueqing, Hu; Zheng, Gong; Yin, Shi; Foster, Dai Fa

2011-11-01

433

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

NASA Astrophysics Data System (ADS)

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

Jackson, Suzy A.

2004-06-01

434

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

435

Capacity and Mutual Information of Wideband Multipath Fading Channels  

Microsoft Academic Search

In this paper we will investigate the capacity and mutual information of a broadbandfading channel consisting of a finite number of time-varying paths. We willshow that the capacity of the channel in the wideband limit is the same as thatof a wideband Gaussian channel with the same average received power. However,the input signals needed to achieve the capacity must be

Emre Telatar; David Tse

1999-01-01

436

Wireless Networking  

Microsoft Academic Search

computing leaders at a number of such campuses 1 shows that wireless on campus leads to some obvious results. Students, faculty and staff move to own more laptops and take them from place to place on campus more than the ever did with wired connections. Dining rooms, libraries, lawns, athletics facilities, offices, hallways and classrooms become places for email, surfing

Frank Steen

2001-01-01

437

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

438

A method for integrating Narrowband TDMA into Wideband TDMA networks  

NASA Astrophysics Data System (ADS)

Time Division Multiple Access (TDMA) is being utilized widely in domestic and international communication networks. The types of TDMA networks in operation fall into two categories: Wideband and Narrowband. In the past few years, a number of Wideband and Narrowband TDMA networks have gone into operation. However, these networks have typically operated as independent nets. As the existing Wideband TDMA networks expand into cities with a smaller amount of originating traffic, a major economic problem occurs. It becomes difficult to justify the cost of a Wideband TDMA station for the smaller amount of traffic. This paper presents an approach that solves the above problem by using a technique where an integrated network with Wideband TDMA for the large cities and Narrowband TDMA for the smaller cities can be used in the same network.

Kaul, P.

439

Enhanced wireless access technologies and experiments for W-CDMA communications  

Microsoft Academic Search

This article reviews enhanced wireless access technologies and experimental evaluations of the wideband DS-CDMA physical layer employing intercell asynchronous operation with a three-step fast cell search method, pilot symbol-assisted coherent links, signal-to-interference plus background noise power ratio-based fast transmit power control, site diversity (soft\\/softer handover), and transmit diversity in the forward link. The article also presents link-capacity-enhancing techniques such as

I. Sawahashi; Kenichi Higuchi; Shinya Tanaka; F. Adachi

2000-01-01

440

Wide-Band Spectra of Prompt Emission  

NASA Astrophysics Data System (ADS)

The Fermi observatory has detected GeV photons from several GRBs. Some of them show an extra spectral component, which is a hint for emission mechanism of GRBs. Here we discuss the GeV emission mechanism according to several promising models. The difference between models will appear in temporal evolution of the photon spectrum. To verify this, instruments that can obtain high photon statistics like CTA are desired. We also discuss the photosphere model, which is recently supported by wide-band observations with Fermi.

Asano, K.

2013-07-01

441

Compact super-wideband optical antenna  

NASA Astrophysics Data System (ADS)

We present progress on advanced optical antennas, which are compact, small size-weight-power units capable to receive super wideband radiated RF signals from 30 MHz to over 3 GHz. Based on electro-optical modulation of fiber-coupled guided wave light, these dielectric E-field sensors exhibit dipole-like azimuthal omni directionality, and combine small size (<< ?RF) with uniform field sensitivity over wide RF received signal bandwidth. The challenge of high sensitivity is addressed by combining high dynamic range photonic link techniques, multiple parallel sensor channels, and high EO sensing materials. The antenna system photonic link consists of a 1550 nm PM fiber-pigtailed laser, a specialized optical modulator antenna in channel waveguide format, a wideband photoreceiver, and optical phase stabilizing components. The optical modulator antenna design employs a dielectric (no electrode) Mach-Zehnder interferometer (MZI) arranged so that sensing RF bandwidth is not limited by optical transit time effects, and MZI phase drift is bias stabilized. For a prototype optical antenna system that is < 100 in3, < 10 W, < 5 lbs, we present test data on sensitivity (< 20 mV/m-Hz1/2), RF bandwidth, and antenna directionality, and show good agreement with theoretical predictions.

Wang, Wen C.; Forber, Richard; Bui, Kenneth

2009-05-01

442

A 3-10 GHz ultra-wideband SiGe LNA with wideband LC matching network  

Microsoft Academic Search

A fully-integrated SiGe wide band amplifier implemented in a standard low cost 0.35 mum process up to 12 dB of gain and a bandwidth of 3-10 GHz is presented. This circuit is divided in 3 stages. The first one is the input matching where the use of an inductively degenerated amplifier is expanded by embedding the input network of the

J. del Pino; S. L. Khemchandani; H. García; R. Pulido; A. Goñi; A. Hernández

2007-01-01

443

Human++: autonomous wireless sensors for body area networks  

Microsoft Academic Search

This paper gives an overview of the results of BMEC's Human++ research program. This program aims to achieve highly miniaturized and autonomous sensor systems that enable people to carry their personal body area network. The body area network will provide medical, lifestyle, assisted living, sports or entertainment functions. It combines expertise in wireless ultra-low power communications, packaging, 3D integration technologies,

Bert Gyselinckx; Chris Van Hoof; Julien Ryckaert; Refet Firat Yazicioglu; Paolo Fiorini; Vladimir Leonov

2005-01-01

444

Radio resource optimization in an UWB wireless access  

Microsoft Academic Search

The Ultra Wide Band (UWB) radio is a promising technology for wireless digital communications. In this paper we present the main principles for the radio resource sharing in UWB. We describe both the theoretical approach and the practical one and we address the procedures of a MAC protocol for the support of Dynamic Bandwidth service class and Reserved one. I.

F. Cuomo; A. Baiocchi; F. Capriotti; C. Martello

2002-01-01

445

Neural signal sampling via the low power wireless pico system.  

PubMed

This paper presents a powerful new low power wireless system for sampling multiple channels of neural activity based on Texas Instruments MSP430 microprocessors and Nordic Semiconductor's ultra low power high bandwidth RF transmitters and receivers. The system's development process, component selection, features and test methodology are presented. PMID:17946727

Cieslewski, Grzegorz; Cheney, David; Gugel, Karl; Sanchez, Justin C; Principe, Jose C

2006-01-01

446

Low-Profile Radiators in Non-Periodic Wideband Arrays.  

National Technical Information Service (NTIS)

This report details our research progress during the course of this grant. This report includes development of new wideband antenna elements, strategies for cost-effective random arrays using these elements, and supporting computational codes. First, a su...

E. Michielssen G. Cung J. T. Bernhard K. C. Kerby P. E. Mayes

2006-01-01

447

Thin-Film Hybrid Microcircuit Wide-Band Noise Generator.  

National Technical Information Service (NTIS)

The knowledge and experience gained through previous fabrication and evaluation of thin-film components in the Electronic Components Laboratory is applied to an electronic circuit known as a 'wideband amplitude noise generator.' The thin-film noise genera...

R. A. Reitmeyer S. Firestone H. C. Frankel

1969-01-01

448

Fabrication of LED based Ultra Slim Optical Pointing Device  

Microsoft Academic Search

The Ultra Slim Optical Pointing Device (USOPD) is a slim optical mouse as an input device for the application of wireless portable personnel communication device like a smart phone. In this paper, we have fabricated optical components of GaN LED based USOPD. The USOPD consist of illumination optical components and imaging lens. LED beam shaping lens consisting of both aspheric

Jae Young Joo; Do-Kyun Woo; Sun Sub Park; Sun-Kyu Lee

2010-01-01

449

Hummingbird: Ultra-Lightweight Cryptography for Resource-Constrained Devices  

Microsoft Academic Search

Due to the tight cost and constrained resources of high- volume consumer devices such as RFID tags, smart cards and wireless sensor nodes, it is desirable to employ lightweight and specialized cryp- tographic primitives for many security applications. Motivated by the design of the well-known Enigma machine, we present a novel ultra- lightweight cryptographic algorithm, referred to as Hummingbird, for

Daniel Engels; Xinxin Fan; Guang Gong; Honggang Hu; Eric M. Smith

2010-01-01

450

Design of Wide-Band Sampled-Data Filters  

Microsoft Academic Search

The frequency domain of wide-band linear sampleddata filters is considered. The sampled-data filter is termed ¿wideband¿ when the frequency range of useful approximation to its continuous counterpart approaches half the sampling frequency. Sampled-data filter representations for continuous filters can be obtained using several different design procedures.[1] A particular design method utilizing the bilinear transformation is developed. The method is especially

Roger Golden; James Kaiser

1968-01-01

451

A wide-band printed double-sided dipole array  

Microsoft Academic Search

A 32-element wide-band printed dipole array is analyzed and successfully implemented. The elements used are double-sided printed dipoles fed with a balanced twin-lead transmission line. A wide-band balun and a launcher system for the array were designed and implemented. Excellent correlation between simulated and measured radiation patterns was observed and good overall performance with a bandwidth in excess of an

B. G. Duffley; G. A. Morin; M. Mikavica; Y. M. M. Antar

2004-01-01

452

Infoseek Ultra  

NSDL National Science Digital Library

Infoseek Corp. has released a Beta version of its new Ultra search engine. It supports Boolean AND/OR/NOT, phrase, case sensitive, and field searching, and supplies relevance feedback with results. It has indexed over 50 million web pages, and claims to make your web page available in its database immediately on submission. It also claims to be the first real-time index of the Internet (through real-time indexing by its spider technology).

453

Wideband, planar, log-periodic balun  

Microsoft Academic Search

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

Mahmoud Basraoui; S. N. Prasad

1998-01-01

454

Modulation spectroscopy of wide-band semiconductors  

NASA Astrophysics Data System (ADS)

The papers presented in this volume provide an overview of recent modulation spectroscopy studies of the optical and photoelectric properties of some wide-band semiconductors, such as III-IV (ZnS, CdS, and ZnTe), III-V (InP), and II-III-VI (CdCa2S4 and ZnIn2S4) compounds. It is shown that the shape of the exciton reflection lines of the materials studied is consistent with the theory of exciton-phonon interaction. Reflection spectrum singularities associated with exciton-phonon complexes have been identified in II-VI crystal. Absorption and emission bands related to point and associated defects have been determined by using electromodulation and gamma modulation methods.

Galanin, M. D.

455

Wideband spectrometer for HIFI-FIRST  

NASA Astrophysics Data System (ADS)

The wideband acousto-optical spectrometer (WBS) for HIFI- FIRST is comprised of two array-AOS with 4 times 1 GHz bands each. There are some advantages to this design, the most important one is that relative frequency and amplitude variations between the 4 bands are rather unlikely. This is demonstrated by laboratory tests, which verify also that fairly slow beam-switching at 0.5 Hz may be a sufficient chop speed for HIFI. The performance of array-AOS has also been demonstrated during measurements at ground-based observatories. WBS consists of three independent units, one IF-, one optics-, and one electronics-unit. Some of the details of the WBS design are described, and the present performance estimates are given.

Schieder, Rudolf T.; Siebertz, Oliver; Schloeder, F.; Gal, Csaba; Stutzki, Juergen; Hartogh, Paul; Natale, Vincenzo

2000-07-01

456

Wideband sensitivity analysis of plasmonic structures  

NASA Astrophysics Data System (ADS)

We propose an adjoint variable method (AVM) for efficient wideband sensitivity analysis of the dispersive plasmonic structures. Transmission Line Modeling (TLM) is exploited for calculation of the structure sensitivities. The theory is developed for general dispersive materials modeled by Drude or Lorentz model. Utilizing the dispersive AVM, sensitivities are calculated with respect to all the designable parameters regardless of their number using at most one extra simulation. This is significantly more efficient than the regular finite difference approaches whose computational overhead scales linearly with the number of design parameters. A Z-domain formulation is utilized to allow for the extension of the theory to a general material model. The theory has been successfully applied to a structure with teethshaped plasmonic resonator. The design variables are the shape parameters (widths and thicknesses) of these teeth. The results are compared to the accurate yet expensive finite difference approach and good agreement is achieved.

Ahmed, Osman S.; Bakr, Mohamed H.; Li, Xun; Nomura, Tsuyoshi

2013-03-01

457

Pediatric applications of wideband acoustic immittance measures.  

PubMed

Wideband acoustic immittance (WAI) measures have potential capability to improve newborn hearing screening outcomes and middle ear diagnosis for infants and children. To fully capitalize on these immittance measures for pediatric hearing care, developmental and pathologic effects need to be fully understood. Published literature on wideband immittance (reflectance, absorbance, tympanometry, and acoustic reflexes) is reviewed in this article to determine pathologic effects in newborns, infants, and children relative to standard audiologic tests such as otoacoustic emissions (OAEs), standard tympanometry, air and bone conduction auditory brainstem response, and otoscopy. Infants and children with surgically confirmed otitis media with effusion have lower absorbance in the mid-frequency range (1 to 3 kHz) for the affected ear(s). Newborns that do not pass OAE screening at birth also have lower absorbance for frequencies from 1 to 3 kHz, suggesting that nonpass results are frequently associated with middle ear issues at birth. In Newborn Hearing Screening Programs, WAI may help to interpret hearing screening results. Conclusions are limited by the fact that the true status of the middle ear and cochlea are not known for newborns and infants in studies that use OAE or tympanometry as the reference standard. Likelihood ratios for reflectance against surgery gold standards range from diagnostically suggestive to informative. Although some of the results are promising, limited evidence and methodological considerations restrict the conclusions that can be drawn regarding the diagnostic accuracy of WAI technologies in infants and children. Additional investigations using stronger gold standard comparisons are needed to determine which tools can most accurately predict middle ear status in the pediatric population. PMID:23900177

Hunter, Lisa L; Prieve, Beth A; Kei, Joseph; Sanford, Chris A

2013-07-01

458

Wideband Hyperspectral Imaging for Space Situational Awareness  

NASA Astrophysics Data System (ADS)

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 or in shadow. WHSI systems can provide imagery with fine spatial detail but do not require this fine spatial resolution to characterize targets. It has been shown previously that multi-color photometry using distinct channels in the VNIR part of the spectrum can be used to identify objects that are similar to one another and perform some non-resolved object characterization (NROC). Wideband HSI systems collect a much richer signature from each object with the potential to fingerprint and identify specific space objects smaller than one pixel. WHSI provides unique information on the properties of space objects. Its ability to characterize objects smaller than a pixel is extremely valuable in developing situational awareness of targets at GEO, MEO, and HEO. WHSI can be deployed with cost-efficient, small aperture telescopes or be used as adjuncts to existing and planned assets. This paper will describe the utility and capabilities of ground-based and space-based WHSI systems including rapid identification and characterization of space objects, mitigation of interference from the atmosphere, separation of glints from diffuse signatures, determination of status of space objects, and gauging aging effects.

Robinson, I.; Klier, A.

459

Multistage MMSE-DFD Receiver for Ultra-Wide Bandwidth Impulse Radio  

Microsoft Academic Search

An adaptive minimum mean-square error (MMSE) receiver is developed based on the multistage matrix Wiener filter decision feedback detection (MMWF-DFD) scheme for ultra-wideband time-hopping impulse radio in multipath fading channels. The feedforward and feedback filters of the MMWF-DFD receiver are capable of sharing the same calculation basis to alleviate the computational complexity without compromising system performance. Simulation results show that

Chia-Chang Hu; Yong-Sheng Cheng; Shih-Chieh Kuo

2005-01-01

460

Towards Systems Beyond 3G Based on Adaptive OFDMA Transmission Wireless systems that assign different sets of frequencies to different terminals promise to provide high performance to meet the challenging requirements of future systems  

Microsoft Academic Search

High data rates, high spectral efficiency, flexibil- ity, and low delays over the air interface will be important features in next-generation wireless systems. The overall challenge will be packet scheduling and adaptive radio transmission for multiple users, via multiple antennas and over frequency-selective wideband channels. This problem needs to be structured to obtain feasible solutions. The basic simplifying assumptions used

Mikael Sternad; Tommy Svensson; Tony Ottosson; Anders Ahlen; Arne Svensson; Anna Brunstrom

461

Wide band cryogenic ultra-high vacuum microwave absorber  

DOEpatents

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

Campisi, Isidoro E. (Newport News, VA)

1992-01-01

462

A Frequency Synthesizer With Optimally Coupled QVCO and Harmonic-Rejection SSBmixer for Multi-Standard Wireless Receiver  

Microsoft Academic Search

This paper presents a wide-band fractional-N fre- quency synthesizer for multi-standard cellular and short-range wireless communication receivers. The synthesizer covers the frequency band from 1.8 to 6 GHz and supports the standards of DCS1800, WCDMA, TD-SCDMA, WLAN802.11 a\\/b\\/g and Bluetooth. Architecture design and frequency planning are care- fully performed to tradeoff wide frequency rang ea nd power efficiency. A quadrature

Deping Huang; Wei Li; Jin Zhou; Ning Li; Jinghong Chen

2011-01-01

463

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

2012-11-22

464

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.

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

2012-01-01

465

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

466

A wideband bidirectional antenna using truncated circular sector fed by rectangular monopole  

Microsoft Academic Search

This paper presents a wideband bidirectional antenna using rectangular monopole with trident to excite truncated circular sector. The antenna is designed for wideband operation, especially when the antenna can satisfy the requirement of low-cost, linear polarization and bidirectional pattern. The simulation results are presented the wideband performance of this antenna. The return loss better than 10 dB covers the frequency

T. Tipsawate; C. Phongcharoenpanich; S. Kosulvit

2009-01-01

467

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

PubMed

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

Rush, Alexander D; Troyk, Philip R

2012-08-21

468

Wireless [From the Editor  

Microsoft Academic Search

Wireless technology is pervasive in our world today. Everywhere we look, we encounter some sort of wireless device—be it the mobile telephone in our pocket or the garage door opener in our car. We see wireless devices in our home in the form of remote controls for our televisions, video games, local networks for our computers, or remote controls for

Michael Neuman

2011-01-01

469

Wireless Network Security  

Microsoft Academic Search

Wireless networking is inherently insecure. From jamming to eavesdropping, from man-in- the middle to spoofing, there are a variety of attack methods that can be used against the users of wireless networks. Modern wireless data networks use a variety of cryptographic techniques such as encryption and authentication to provide barriers to such infiltrations. However, much of the commonly used security

Partha Dasgupta; Tom Boyd

470

Challenges: Wireless Web Services  

Microsoft Academic Search

This paper describes the challenges of adapting existing web-service architecture to the wireless environment. It presents a new, wireless, web-service architecture based on the smart client model that can address some of the fundamental differences between the wireless and wireline environments. The fundamental differences between these environments can be called the mobile challenges, including (1) the unpredictable nature of the

Hao-hua Chu; Chuang-wen You; Chao-ming Teng

2004-01-01

471

Challenges: wireless Web services  

Microsoft Academic Search

This paper describes the challenges of adapting existing Web-service architecture to the wireless environment. It presents a new, wireless, Web-service architecture based on the smart client model that can address some of the fundamental differences between the wireless and wireline environments. The fundamental differences between these environments can be called the mobile challenges, including (1) the unpredictable nature of the

Hao-hua Chu; Chuang-wen You; Chao-ming Teng

2004-01-01

472

Wireless steganography  

NASA Astrophysics Data System (ADS)

Modern mobile devices are some of the most technologically advanced devices that people use on a daily basis and the current trends in mobile phone technology indicate that tasks achievable by mobile devices will soon exceed our imagination. This paper undertakes a case study of the development and implementation of one of the first known steganography (data hiding) applications on a mobile device. Steganography is traditionally accomplished using the high processing speeds of desktop or notebook computers. With the introduction of mobile platform operating systems, there arises an opportunity for the users to develop and embed their own applications. We take advantage of this opportunity with the introduction of wireless steganographic algorithms. Thus we demonstrates that custom applications, popular with security establishments, can be developed also on mobile systems independent of both the mobile device manufacturer and mobile service provider. For example, this might be a very important feature if the communication is to be controlled exclusively by authorized personnel. The paper begins by reviewing the technological capabilities of modern mobile devices. Then we address a suitable development platform which is based on SymbianTM/Series60TM architecture. Finally, two data hiding applications developed for SymbianTM/Series60TM mobile phones are presented.

Agaian, Sos S.; Akopian, David; D'Souza, Sunil

2006-02-01

473

Wideband frequency response of low-metal mines  

NASA Astrophysics Data System (ADS)

Extensive studies of in-air testing of various metal detectors have been previously performed for a wide variety of targets and operating conditions. Using similar targets, we conducted a preliminary evaluation of a laboratory prototype wideband metal detector operating in the frequency domain (FD) under development at Quantum Magnetics. The wideband metal detector uses a small magnetoresistive (MR) sensor instead of an induction coil in the receive chain and can collect frequency response signatures of targets in the frequency band 100 Hz-150 kHz, thereby providing a more complete picture of a low metal mine response. These results suggest that wideband metal detection can play an important role in improving the false alarm rate (FAR) in a common detector platform by improving the amount of information provided to the fused algorithm process.

Dalichaouch, Yacine; Whitecotton, Brian W.; McManus, Tobin; Kuhn, Steve; Trammell, Hoke S.; Shelby, Richard A.; Carin, Lawrence

2004-09-01

474

The wideband feed system on the Australia telescope  

NASA Astrophysics Data System (ADS)

The Australia Telescope is a new synthesis instrument for radio astronomy observations, which incorporates the existing 64-m-diam Parkes radio telescope with seven new 22-m-diam Cassegrain antennas. This paper describes the design and the operation of the wideband feed system developed to meet the demands of this telescope system. The feed system includes two types of wideband corrugated conical feed horns which are mounted on a rotating turret system (which allows each feed horn to be brought on axis as required). Special attention is given to the design of orthomode transducers (OMTs) which immediately follow each feed horn in order to separate the two orthogonal linearly polarized wideband signals. Diagrams of the rotating turret system and an OMT are included.

James, G. L.; Skinner, S. J.

475

Wireless adiabatic power transfer  

SciTech Connect

Research Highlights: > Efficient and robust mid-range wireless energy transfer between two coils. > The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. > Wireless energy transfer is insensitive to any resonant constraints. > Wireless energy transfer is insensitive to noise in the neighborhood of the coils. - Abstract: We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.

Rangelov, A.A., E-mail: rangelov@phys.uni-sofia.bg [Department of Physics, Sofia University, James Bourchier 5 blvd., 1164 Sofia (Bulgaria); Suchowski, H.; Silberberg, Y. [Department of Physics of Complex System, Weizmann Institute of Science, Rehovot 76100 (Israel); Vitanov, N.V. [Department of Physics, Sofia University, James Bourchier 5 blvd., 1164 Sofia (Bulgaria)

2011-03-15

476

75 FR 8400 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...  

Federal Register 2010, 2011, 2012, 2013

...Wireless Communications System Server Software, Wireless Handheld Devices and Battery Packs; Notice...wireless communications system server software, wireless handheld devices and battery packs by...wireless communications system server software, wireless handheld devices or battery packs...

2010-02-24

477

Design of wideband circularly polarized aperture-coupled microstrip antennas  

NASA Astrophysics Data System (ADS)

Two variations of a novel feeding technique for a wideband circularly polarized aperture-coupled microstrip antenna are described. Prototype designs for wideband linearly polarized elements are first presented, and then used for circularly polarized designs. Techniques used for design of the feed network are detailed, for both series feed and parallel feed versions. Experimental results are shown for each antenna, and results for the two designs are compared. The impedance and axial ratio bandwidths for these antennas are among the best yet achieved for microstrip antenna elements. Several design variations are also discussed.

Targonski, Stephen D.; Pozar, David M.

1993-02-01

478

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

Microsoft Academic Search

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

M. M. Tentzeris

2008-01-01

479

Compact planar ultra-wide pass-band filters with source-load coupling and impedance stubs  

Microsoft Academic Search

New configurations of folded and compact planar ultra-wideband filters with source- load cross coupling and impedance stubs are presented. Stepped impedance resonators and coupled-line sections as inverter circuits form the basic filter structures. High-low impedance lines connect individual resonators. Effective techniques such as open-stub lines and source-load cross coupling are utilized in order to add return-loss poles in the pass-band

Marjan Mokhtaari; Jens Bornemann; Smain Amari

2006-01-01

480

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

481

Transmission of ultra wide band radio using multimode radio-over-fiber system  

Microsoft Academic Search

Existing regulatory restricts wireless range of ultra wide band (UWB) radio communication distances to several tens of meters due to its low transmit power. This paper introduces multimode radio-over-fiber (ROF) to extend the range of wireless UWB radios. In this work, UWB pulses are transmitted over multimode RoF to realise a low cost distributed antenna system. Single mode RoF tends

C. M. Tan; L. C. Ong; M. L. Yee; B. Luo; P. K. Tang

2005-01-01

482

Wideband radio channel measurement system at 2 GHz  

Microsoft Academic Search

This paper describes the wideband radio channel sounding techniques for mobile radio channel measurements. Implementation of the cross-correlation method using both a sliding correlator and a matched filter detector is presented. Limitations and accuracy of radio channel measurements are discussed. Typically, delay resolution of about 20 ns is achieved with 100 MHz bandwidth. With a sliding correlator, a dynamic range

Jarmo Kivinen; Timo O. Korhonen; Pauli Aikio; Ralf Gruber; Pertti Vainikainen; S.-G. Haggman

1999-01-01

483

Noncontact Tremor Characterization Using Low-Power Wideband Radar Technology  

Microsoft Academic Search

Continuous monitoring and analysis of tremor is important for the diagnosis and establishment of treatments in many neurological disorders. This paper describes noncontact assessment of tremor characteristics obtained by an experimental new ultrawideband (UWB) system. The system is based on transmission of a wideband electromagnetic signal with extremely low power, and analysis of the received signal, which is composed of

Gaddi Blumrosen; Moshe Uziel; Boris Rubinsky; Dana Porrat

2012-01-01

484

A Novel Wideband and Compact Microstrip Grid Array Antenna  

Microsoft Academic Search

A wideband and compact microstrip grid array antenna is presented. The antenna is printed on a dielectric substrate, backed by a metal board, and directly fed from a 50 ?? coaxial cable. It adopts elliptical radiation elements to enhance its impedance and gain bandwidths, and sinusoid lines to reduce its size. Structural parameters of a proposed antenna with 7 radiation

Xing Chen; Guosheng Wang; Kama Huang

2010-01-01

485

A novel wideband and compact microstrip grid array antenna  

Microsoft Academic Search

A wideband and compact microstrip grid array antenna is presented. The antenna is printed on a dielectric substrate, backed by a metal board, and directly fed from a 50? coaxial cable. It adopts elliptical radiation elements to enhance its impedance and gain bandwidths, and sinusoid lines to reduce its size. Structural parameters of a proposed antenna with 7 radiation elements

Guosheng Wang; Shuiyang Lin; Kaifu Pan; Xiaoguang Ge; Yang Yang

2010-01-01

486

Microstrip-Fed Wideband Circularly Polarized Printed Antenna  

Microsoft Academic Search

A wideband circularly-polarized printed antenna is proposed, which employs an asymmetrical dipole and a slit in the ground plane which are fed by an L-shaped microstrip feedline using a via. The proposed antenna geometry is arranged so that the orthogonal surface currents, which are generated in the dipole, feedline and ground plane, have the appropriate phase to provide circular polarization.

Xiu Long Bao; Max J. Ammann; Patrick McEvoy

2010-01-01

487

Application of inverse chirp-z transform in wideband radar  

Microsoft Academic Search

Pulse stepped frequency radar is a kind of wideband radar technique. It can obtain high range resolution by correct signal processing methods. One of most important methods is the inverse Fourier transform method. This method can realize pulse compression by the coherent sum of a series of echoes. Although the inverse Fourier transform method is very useful, the number of

Wang Yiding; Wu Yirong; Hong Jun

2001-01-01

488

Wideband STAP (WB-STAP) for passive sonar  

Microsoft Academic Search

This paper addresses an innovative method for passive sonar signal processing where it is required to suppress a field of moving acoustic interferes while simultaneously enhancing the signal from a weak moving source. Motivated by the Space-Time Adaptive Processing (STAP) technology for similar radar applications, we propose a solution to the passive broadband sonar problem using Wideband Space-Time Adaptive Processing

S. U. Pillai; J. R. Guerci; S. R. Pillai

2003-01-01

489

Ruggedizing printed circuit boards using a wideband dynamic absorber  

Microsoft Academic Search

The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB) for use in hostile industrial and military environment are either insufficient or expensive. This paper addresses a novel approach towards ruggedizing commercial-off-the-shelf PCBs using a miniature wideband dynamic absorber. The optimisation technique used relies on the experimentally measured vibration spectra

V. C. Ho; A. M. Veprik; V. I. Babitsky

2003-01-01

490

A wide-band 20W LMOS Doherty power amplifier  

Microsoft Academic Search

This work discusses the efficiency bandwidth constrains in Doherty amplifiers. An analysis of the bandwidth limitations imposed by the impedance inverter and output capacitance of the active devices is given. Alternative wideband matching and output connection schemes for Doherty amplifiers are evaluated for their efficiency performance both at full output power, as well as, in power back-off operation. The presented

J. H. Qureshi; N. Li; W. C. E. Neo; F. van Rijs; I. Blednov; L. C. N. de Vreede

2010-01-01

491

Wideband underwater acoustic CDMA: adaptive multichannel receiver design  

Microsoft Academic Search

Two receivers that utilize multichannel (array) processing of asynchronous wideband direct-sequence CDMA signals are proposed: the symbol decision feedback (SDF) receiver and the chip hypothesis feedback (CHF) receiver. In the SDF configuration, receiver parameters are adapted at the symbol rate. This limits its applicability to the channels whose time variation is slow compared to the symbol rate, which may not

Milica Stojanovic; Lee Freitag

2005-01-01

492

Multichannel Detection for Wideband Underwater Acoustic CDMA Communications  

Microsoft Academic Search

Direct-sequence (DS) code-division multiple access (CDMA) is considered for future wideband mobile underwater acoustic networks, where a typical configuration may include several autonomous underwater vehicles (AUVs) 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)

Milica Stojanovic; Lee Freitag

2006-01-01

493

Real-time wideband cylindrical holographic surveillance system  

Microsoft Academic Search

A wideband holographic cylindrical surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing

David M. Sheen; Douglas L. McMakin; Thomas E. Hall; Ronald H. Severtsen

1999-01-01

494

Real-time wideband cylindrical holographic surveillance system  

Microsoft Academic Search

A wideband holographic cylindrical surveillance system is disclosed 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

D. M. Sheen; D. L. McMakin; T. E. Hall; R. H. Severtsen

1999-01-01

495

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

496

Wireless security in mobile health.  

PubMed

Mobile health (m-health) is an extremely broad term that embraces mobile communication in the health sector and data packaging. The four broad categories of wireless networks are wireless personal area network, wireless metropolitan area network, wireless wide area network, and wireless local area network. Wireless local area network is the most notable of the wireless networking tools obtainable in the health sector. Transfer of delicate and critical information on radio frequencies should be secure, and the right to use must be meticulous. This article covers the business opportunities in m-health, threats faced by wireless networks in hospitals, and methods of mitigating these threats. PMID:23234427

Osunmuyiwa, Olufolabi; Ulusoy, Ali Hakan

2012-12-01

497

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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

Fred Sabins

2003-10-31

498

Learning with wireless mobile devices and social software  

Microsoft Academic Search

The paper outlines the beginning of research into the synthesis of mobile personal technologies, social technologies, and constructivist pedagogies, and briefly explores the potential for creating student-centred collaborative learning communities using wireless mobile devices (e.g. PDAs, Ultra Mobile PCs, mobile phones and smart-phones) and social software (e.g. blogs, RSS, instant messaging, moodle, elgg etc…). Instead of simply re- purposing content

Thomas Cochrane

499

Dual Carrier Modulation Demapping Methods and Performances for Wireless USB  

Microsoft Academic Search

Dual Carrier Modulation (DCM) was chosen as the higher data rate modulation scheme for MB-OFDM (Multiband Orthogonal Frequency Division Multiplexing) in the UWB (Ultra- Wide Band) radio platform ECMA-368. ECMA-368 has been chosen as the physical implementation for high data rate Wireless USB (W-USB) and Bluetooth 3.0. In this paper, different demapping methods for the DCM demapper are presented, being

Runfeng Yang; R. Simon Sherratt

2008-01-01

500

Versatile low power media access for wireless sensor networks  

Microsoft Academic Search

We propose B-MAC, a carrier sense media access protocol for wireless sensor networks that provides a flexible interface to obtain ultra low power operation, effective collision avoidance, and high channel utilization. To achieve low power operation, B-MAC employs an adaptive preamble sampling scheme to reduce duty cycle and minimize idle listening. B-MAC supports on-the-fly reconfiguration and provides bidirectional interfaces for

Joseph Polastre; Jason L. Hill; David E. Culler

2004-01-01