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1

Ultra wideband technology for wireless sensor networks  

NASA Astrophysics Data System (ADS)

Wireless sensor networks (WSNs) have emerged as an important method for planetary surface exploration. To investigate the optimized wireless technology for WSNs, we summarized the key requirements of WSNs and justified ultra wideband (UWB) technology by comparing with other competitive wireless technologies. We also analyzed network topologies as well as physical and MAC layer designs of IEEE 802.15.4a standard, which adopted impulse radio UWB (IR-UWB) technology. Our analysis showed that IR-UWB-based 802.15.4a standard could enable robust communication, precise ranging, and heterogeneous networking for WSNs applications. The result of our present work implies that UWB-based WSNs can be applied to future planetary surface exploration.

Wang, Yue; Xiong, Weiming

2011-08-01

2

Biorthogonal pulse shape modulation for ultra-wideband wireless communications  

Microsoft Academic Search

We propose a wireless communications ultra-wideband (UWB) multiple access spread spectrum scheme based on biorthogonal pulse shape modulation (BPSM). Unlike classical UWB that employs bit-by-bit spreading, this scheme utilizes symbol-by-symbol spreading which effectively reduces the multiple access interference. Compared to orthogonal UWB using symbol-by-symbol spreading the proposed BPSM technique minimizes the receiver complexity, while causing a negligible performance degradation. The

Nejib Boubaker; Khaled Ben Letaief

2004-01-01

3

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

E-print Network

because of demand for high data-rate transmission. Hence, ultra-wideband antennas have received much attention in mobile wireless communications. Planar monopole ultra-wideband antennas for UHF, microwave, and millimeter-wave bands are developed, with many...

Ren, Yu-Jiun

2009-05-15

4

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

NASA Astrophysics Data System (ADS)

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

Dandu, Varun Kumar

5

Ultra-Wideband and UniDirectional Radiation Slot Antenna for MultiBand Wireless Communication Applications  

Microsoft Academic Search

In this paper, a ultra-wideband slot antenna is proposed and developed for multi-band wireless communication applications.\\u000a The radiating slot is fed by a microstrip line with a microstrip fork shaped tuning stub and backed by a finite metallic reflector.\\u000a The frequency characteristic and radiation performance of the proposed antenna are successfully optimized and the related\\u000a prototypes are fabricated and tested.

Qinjiang Rao; Tayeb A. Denidni

2007-01-01

6

Performance of ultra-wideband time-shift-modulated signals in the indoor wireless impulse radio channel  

Microsoft Academic Search

Impulse radio (IR) is a spread spectrum (SS) wireless technique in which ultra-wideband (UWB) communication waveforms that consist of trains of time-shifted sub-nanosecond pulses are modulated to convey information exclusively in the relative time position of the pulses. We make an assessment of the performance of non-binary IR modulation in the presence of multipath with detection using a RAKE receiver

Fernando Ramirez-Mireles; M. Z. Win; R. A. Scholtz

1997-01-01

7

A Comparison of Ultra Wideband Signal Functions for Wireless Ad Hoc Networks  

Microsoft Academic Search

This paper describes, simulates, evaluates and compares four time and band limited functions that can be used to create ultra wideband signals. Expressions and methods for generating the functions are presented followed with simulations using uniform sets of parameters. It is shown at the -10bB points the Hermite, prolate spheroidal wave function (PSWF) and wavelets have suitable UWB properties. Using

Johnson I. Agbinya; Ha Dang Truong

2005-01-01

8

Ultra-wideband radar sensors and networks  

SciTech Connect

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

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

2013-08-06

9

Ultra-wideband receiver  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1994-01-01

10

Ultra-wideband receiver  

DOEpatents

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

McEwan, T.E.

1996-06-04

11

Ultra-wideband receiver  

DOEpatents

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

McEwan, T.E.

1994-09-06

12

Ultra-wideband receiver  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1996-01-01

13

Pulse-based ultra-wideband transmitters for digital communication  

E-print Network

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

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

2007-01-01

14

CMOS implementation of ultra-wideband systems  

NASA Astrophysics Data System (ADS)

Ultra-Wideband systems is the collective term for wireless devices with a large spectral footprint and a low transmission power. The extreme low power spectral density of the UWB system forms a vast difference with classic communication systems that employ a large power within a small frequency band. Implementation approaches of Ultra-Wideband enclose classical carrier-based OFDM systems and pulse-based systems, each with their play trumps and disadvantages. Depending on the final application, cost, power or bandwidth can be the key target. Deep-submicron technologies allow to extend the limiting boundaries of analog building blocks but also introduce new challenges. Furthermore, new problems with respect to analog design deserve our attention: The high bandwidth of the signals involved in wideband systems obliges to migrate to a broadband receiver chain: LNA's (Low Noise Amplifier), mixers and ADC's with a wideband in- and output have to be designed, while commonly used techniques such as inductive peaking in the power amplifier cannot be used any more. Both advantages and disadvantages of OFDM and pulse-based transceiver architectures will be compared, together with simulation data, in order to give an overview of important design aspects of an Ultra-Wideband application.

Vereecken, Wim; Steyaert, Michiel

2005-06-01

15

Ultra wideband surface wave communications  

NASA Astrophysics Data System (ADS)

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

Lacomb, Julie Anne

16

Ultra-wideband digital baseband  

E-print Network

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

Blázquez-Fernández, Raúl, 1975-

2006-01-01

17

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

18

Ultra-wideband transmitter research  

Microsoft Academic Search

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

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

1998-01-01

19

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

E-print Network

of mobility by eliminating messy cables. Nowadays wireless network are dominated by narrow band systems like Bluetooth, Zigbee and IEEE 802.1a/b/g. Their limited data rate, no more than 54Mb/s, is insufficient to fast transfer large files and high...

Tong, Haitao

2009-05-15

20

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

21

Ultra-wideband directional sampler  

DOEpatents

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

McEwan, T.E.

1996-05-14

22

Ultra-wideband directional sampler  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1996-01-01

23

A platform for ultra wideband communication systems  

E-print Network

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

Ackerman, Nathan (Nathan Joseph)

2005-01-01

24

Antenna design for ultra wideband radio  

E-print Network

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

Powell, Johnna, 1980-

2004-01-01

25

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

E-print Network

Ultra Wideband InterferenceUltra Wideband Interference Effects on an AmateurEffects on an Amateur is the ARRL?What is the ARRL? Amateur radio hobbyists and publicAmateur radio hobbyists and public serviceSensitivity is important 1. http://www.arrl.org #12;Amateur Radio BandsAmateur Radio Bands MHz GHz Mid-Range Imaging Indoor

Southern California, University of

26

Ultra-wideband impedance sensor  

DOEpatents

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

McEwan, T.E.

1999-03-16

27

Ultra-wideband impedance sensor  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1999-01-01

28

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

PubMed

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

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

2012-01-01

29

A novel ultra-wideband microstrip antenna  

Microsoft Academic Search

This paper describes the design of a novel ultra-wideband (UWB) antenna for UWB applications. The design is based on planar rectangular monopole microstrip antenna. The optimum antenna geometry is obtained by computation calculation, and the results were simulated by using electromagnetic simulation software CST MWS(CST microwave studio). The results show that the microstrip antenna can get in the range of

Xiaodong Deng; Xiaodong Yang; Bingcai Chen; Yu Bai

2011-01-01

30

Ultra-wideband source and antenna research  

Microsoft Academic Search

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

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

2000-01-01

31

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

E-print Network

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

Daly, Denis Clarke

2009-01-01

32

Ultra-wideband conformal helmet antenna  

Microsoft Academic Search

This paper presents the development of an ultra-wideband (300 to 3000 MHz), vertically polarized, nearly omni-directional (in azimuth) communications antenna integrated into the camouflage cover of a standard military-issue Kevlar helmet. The Helmet Camouflage Cover Antenna (referred to as the “helmet antenna”) is one of three antennas (with the combined frequency coverage from 2 to 2000 MHz) based on the

J. Lebaric; Ah-Tuan Tan

2000-01-01

33

ULTRA WIDEBAND POWER DIVIDER USING TAPERED LINE  

Microsoft Academic Search

A power divider with ultra-wideband (UWB) performance has been designed. The quarter-wave transformer in the conventional Wilkinson power divider is replaced by an exponentially tapered microstrip line. Since the tapered line provides a consistent impedance transformation across all frequencies, very low amplitude ripple of 0.2dB peak-to-peak in the transmission coe-cient and superior input return loss better than 15dB are achieved

Chun Tong Chiang; Boon-Kuan Chung

2010-01-01

34

Ultra-wideband precision asset location system  

Microsoft Academic Search

A prototype ultra-wideband (UWB) precision asset location (PAL) system was developed and tested aboard the SS Curtiss in Port Hueneme, California. The PAL system was developed to assess the capability of UWB geolocation to operate in severe multipath shipboard environments. The PAL system was based on an earlier UWB relative-time-of-arrival (RTOA) transceiver location system and was extended to a differential-time-of-arrival

Robert J. Fontana; Steven J. Gunderson

2002-01-01

35

Multiple signal waveforms adaptation in cognitive ultra-wideband radio evolution  

Microsoft Academic Search

Cognitive ultra-wideband (UWB) radio is proposed to exploit the advantages and the unique features of enhancing UWB wireless technologies by utilizing cognitive radio functionality. In order to achieve the cognitive UWB radio, multiple pulse waveforms adaptation has been investigated for producing the expected spectral notches while matching with the Federal Communications Commission (FCC) spectral mask. Then the specifically designed pulse

Honggang Zhang; Xiaofei Zhou; Kamya Yekeh Yazdandoost; Imrich Chlamtac

2006-01-01

36

A PPM GAUSSIAN PULSE GENERATOR FOR ULTRA-WIDEBAND COMMUNICATIONS  

E-print Network

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

Serdijn, Wouter A.

37

Ultra Wideband (UWB) communication vulnerability for security applications.  

SciTech Connect

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

Cooley, H. Timothy

2010-07-01

38

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

39

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

40

Ultra-Wideband Low-Noise Amplifier  

NASA Astrophysics Data System (ADS)

Ultra-Wideband (UWB) Low-Noise Amplifier (LNA) is an essential part of the digital TV and UWB signal processor, but what makes it hard to design is the comprehensive consideration of bandwidth, noise and gain control performance. A new solution of high performance amplifier with low-noise, UWB and direct current (DC) is presented (Fig.1), which is composed of a precision pre-amplifier with AD797, a stepped gain controller with VCA810 and a digital potentiometer, an eight-order Bessel low-pass filter with LC network, a zero-drift corrector with the digital compensation method. The test results (Tab 1-3 & Fig.6) show that the gain of amplifier can be adjusted from 0 to 80 dB by step, the fluctuation of the pass band from DC to 10 MHz is less than 0.87 dB, stop-band attenuation reaches -42 dB/2fc, the equivalent input noise voltage is less than 7.2 ?Vrms. This design successfully solves some high challenging contradictions, such as ultra-wideband and low-noise, stop-band attenuation and pass-band fluctuation, precise gain control and DC zero-drift correction.

Lei, Kaizhuo; Su, Jiao; Shang, Jintao; Cui, Quanshun; Yang, Haibo

41

An Ultra-Wideband Amplifier MMIC for 3-10.6 GHz Wireless Applications with InGaP/GaAs HBT Technology  

NASA Astrophysics Data System (ADS)

An ultra-wideband amplifier MMIC has been demonstrated for the Ultra-Wide-Band (UWB) standard with InGaP/GaAs Heterojunction Bipolar Transistor (HBT) technology. The fabricated MMIC chip size is only 0.53 mm by 0.93mm. The amplifier MMIC includes all matching circuits on the chip. This amplifier MMIC is applicable to both a UWB low noise amplifier and a UWB transmitter amplifier by changing the collector current. The operating bias currents are 15 mA for a low noise amplifier and 30 mA for a transmitter amplifier. The collector bias voltage is 3.0 V. The MMIC as a transmitter amplifier exhibits a gain of 16 +/-1 dB and a third-order intercept point at the input (IIP3) of 0 dBm with 6.0 and 6.01 GHz signals with equal amplitude level. As a low noise amplifier, the MMIC exhibits a noise figure of less than 3.7 dB from 3.1 to 10.6 GHz.

Kurachi, Satoshi; Yoshimasu, Toshihiko; Liu, Haiwen; Chen, Jia; Shimamatsu, Yuichiro

42

An ultra-wideband transceiver for biotelemetry systems  

NASA Astrophysics Data System (ADS)

This paper introduces an Ultra-Wideband (UWB) transceiver for in-vivo biotelemetry applications, especially for wireless endoscope. A system modeling, simulation and design trade-off analysis for an UWB impulse radio transceiver is presented that incorporates the human body attenuation effect, the IEEE 802.14a indoor channel model, and channel noise to determine an optimum architecture for the given applications. Based on the system simulation using Matlab, the severe effect from the human body attenuation has been identified and a non-coherent Transmit Reference (TR) Transceiver architecture with differential Binary Phase Shift Keying (DBPSK) modulation was selected as the best option for a communication link in biotelemetry applications. The transceiver consists of an all-digital transmitter with H-bridge output stage type of Pulse Generator (PG), wideband inductorless resistive shunt feedback Low Noise Amplifier (LNA) with thermal noise canceling, Gilbert mixer, Integrator, decision detector and Variable Delay Controller (VDC). The performance characteristics of the PG, LNA and mixer are presented by the circuit simulation results using 0.18?m digital CMOS technology.

Kim, Chul; Lehmann, Torsten; Nooshabadi, Saeid

2007-12-01

43

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

44

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

2008-04-01

45

Cognitive Technology for improving Ultra-Wideband (UWB) Coexistence  

Microsoft Academic Search

Cognitive radio technology enables the opportunistic operation of secondary devices in frequency bands allocated to primary users. In this paper we explore how this technology can enable ultra-wideband (UWB) systems to coexist with primary users. The distinguishing aspect of cognitive radio technology is the ability to detect and avoid primary users. We discuss two options for detecting the presence of

S. M. Mishra; R. W. Brodersen

2007-01-01

46

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

47

Ultra-Wideband Electrical Pulse Generator Using Photoconductive Semiconductor Switches  

Microsoft Academic Search

We achieved the generation of unipolar and bipolar ultra-wideband electrical pulses by using a photoconductive device. It relies on a doped silicon substrate which is used in the linear mode with less optical energy than usually published. This running mode allows the synchronisation of several sources with a timing jitter less than 5 ps. However it permits to control the

B. Vergne; V. Couderc; A. Barthelemy; M. Lalande; V. Bertrand; D. Gontier

2005-01-01

48

Distance bounded energy detecting ultra-wideband impulse radio secure protocol.  

PubMed

We present a demonstration of a novel protocol for secure transmissions on a Ultra-wideband impulse radio that includes distance bounding. Distance bounding requires radios to be within a certain radius to communicate. This new protocol can be used in body area networks for medical devices where security is imperative. Many current wireless medical devices were not designed with security as a priority including devices that can be life threatening if controlled by a hacker. This protocol provides multiple levels of security including encryption and a distance bounding test to prevent long distance attacks. PMID:25571513

Hedin, Daniel S; Kollmann, Daniel T; Gibson, Paul L; Riehle, Timothy H; Seifert, Gregory J

2014-08-01

49

LTCC-based ultra-wideband Linearly Tapered Slot Antenna design guidelines  

Microsoft Academic Search

In this paper, the design of antipodal non-planar linearly tapered slot antenna (LTSA) designed in LTCC technology with wide bandwidth operation for ultra-wideband applications and a practical design guideline of LTCC-based ultra wideband LTSA is presented. The LTCC-based ultra wideband LTSA characteristics are investigated and then compared to a compact antipodal LTCC-based Vivaldi design. Using microstrip feeding technique, the antenna

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

2009-01-01

50

A COMPACT ULTRA-WIDEBAND MICROSTRIP ANTENNA WITH MULTIPLE NOTCHES  

Microsoft Academic Search

In this paper, a new compact circular monopole ultra- wideband antenna with multiple narrow bands notched is proposed, which is implemented by using the existing techniques, such as loading a L-type band-stop filter, inserting a split ring resonator (SRR), and the method we proposed that connecting L branches on the radiation disk. Four sharp notches at 2.4GHz, 3.5 GHz, 5.5

C. Yin; L. Ruan; S.-G. Mo; Jia-Hui Chu

2008-01-01

51

Ultra-wideband Active Receiving Array Antenna with Dual Polarization  

NASA Astrophysics Data System (ADS)

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

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

52

Ultra-wideband pulse generation using turbo-switches  

NASA Astrophysics Data System (ADS)

We propose and experimentally demonstrate a novel method for generating ultra-wideband (UWB) monocycle pulse by exploiting a turbo-switch which consists of two reflective semiconductor optical amplifiers (RSOAs). By adjusting the currents applied to both RSOAs, the monocycle pulse is realized due to the gain overshoot induced by the turbo-switch. The polarity inversed monocycle pairs and the UWB doublet pulse train are numerically realized by cascading turboswitches.

Zhang, Weiwei; Sun, Junqiang; Cheng, Cheng; Zhang, Xinliang; Huang, Dexiu

2008-11-01

53

Receiver improvement for ultra-wideband transmitted-reference systems  

Microsoft Academic Search

The optimality of the cross-correlation receiver for ultra-wideband (UWB) transmitted-reference (TR) systems is first justified as the optimal linear combiner with a noisy reference. In light of the observation that combining all the available paths with a noisy reference may lead to inferior performance to that of combining just some of them, a weighted cross-correlation receiver is proposed based on

Meng-Hsuan Chung; Robert A. Scholtz

2005-01-01

54

An Overview of the Recent Wideband Transcutaneous Wireless Communication Techniques  

PubMed Central

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

Ghovanloo, Maysam

2013-01-01

55

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

Microsoft Academic Search

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

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

2006-01-01

56

Cognospectrum: spectrum adaptation and evolution in cognitive ultra-wideband radio  

Microsoft Academic Search

Cognitive ultra wideband (UWB) radio is proposed to exploit the advantages of combining cognitive radio with ultra wideband technologies. In order to realize cognitive UWB radio, multiple pulse waveform adaptations have been investigated for producing the expected spectral notches while matching with FCC spectral mask and other frequency regulation requirements. To verify the pulse distortion effect of UWB antenna on

Xiaofei Zhou; Kamya Y. Yazdandoost; Honggang Zhang; Imrich Chlamtac

2005-01-01

57

A 2.4 GHz Differential Wavelet Generator in 0.18 ?m Complementary Metal-Oxide-Semiconductor for 1.4 Gbps Ultra-Wideband Impulse Radio in Wireless Inter/Intra-Chip Data Communication  

NASA Astrophysics Data System (ADS)

Ultra-wideband impulse based radio systems use Gaussian monocycle pulses as transmitted signals at the transmitting end and as template signals at the receiving end. In this paper we present a new fully integrated differential Gaussian monocycle pulse generator in 0.18 ?m complementary metal-oxide-semiconductor (CMOS) technology. Here the Gaussian monocycle pulse is generated from triangular shaped pulse by a single differentiator circuit and it is then converted into differential form by using a single input to dual output amplifier. The developed circuit occupies a small area of 0.06 mm2 and consumes a total power of 44 mW at 1.8 V. The transmission of the generated differential Gaussian monocycle pulse at a rate of 1.4 Gbps through integrated dipole antenna in the same Si-substrate for intrachip communication in future ultralarge scale integrated circuit (ULSI) is verified by simulation and results are presented here.

Saha, Pran Kanai; Sasaki, Nobuo; Kimoto, Kentaro; Kikkawa, Takamaro

2006-04-01

58

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

59

A reconfigurable software defined ultra-wideband impulse radio transceiver  

NASA Astrophysics Data System (ADS)

An ultra-wideband (UWB) software defined radio (SDR) implementation is presented. The developed impulse radio (IR) transceiver employs first order bandpass (BP) sampling at a conversion frequency which is four times the channel bandwidth. The subsampling architecture directly provides the RF signal avoiding any non-ideal mixer stages and reduces the requirements of digital signal processing implemented in a field programmable gate array (FPGA). The transmitter consists basically of a multi-Nyquist digital to analog converter (DAC), whereas the implemented matched filter (MF) receiver prototype employs a standard digitizing oscilloscope. This design can be adaptively reconfigured in terms of modulation, data rate, and channel equalization. The reconfigurable design is used for an extensive performance analysis of the quadrature phase shift keying (QPSK) modulation scheme investigating the influence of different antennas, amplifiers, narrowband interferers as well as different equalizer lengths. Even for distances up to 7 m in a multipath environment robust communication was achieved.

Blech, M. D.; Ott, A. T.; Neumeier, P.; Möller, M.; Eibert, T. F.

2010-09-01

60

Ultra-wideband horn antenna with abrupt radiator  

DOEpatents

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

McEwan, T.E.

1998-05-19

61

Ultra-wideband horn antenna with abrupt radiator  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1998-01-01

62

Ultra-wideband Location Authentication for Item Tracking  

SciTech Connect

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

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

2012-01-01

63

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

2012-06-01

64

Clear Channel Assessment in Ultra-Wideband Sensor Networks  

NASA Astrophysics Data System (ADS)

Impulse ultra-wideband (UWB) is an attractive technology for large ad hoc sensor networks due to its precise ranging capacity, multi-path fading robustness and low radiation power. The transient and carrier-less nature of low radiation pulse and harsh multipath channel condition makes it cumbersome to implement carrier sensing. We proposed clear channel assessment (CCA) based on preamble-assisted modulation (PAM) for UWB sensor networks. Preamble symbols are periodically inserted into the frame payload in the time domain to serve as regular feature for reliable CCA. We simulated the CCA performance in the multipath UWB channel model developed by IEEE 802.15.4a. PAM and CCA configurations were optimized for the distributed carrier sense multiple access protocol. PAM was accepted by 802.15.4a group as an optional feature. Furthermore, the multiplexed preamble symbols can be exploited for channel estimation to improve communication and ranging.

Zhen, Bin; Li, Huan-Bang; Kohno, Ryuji

65

All-optical ultra-wideband monocycle pulse generation using polarization state rotation filtering  

NASA Astrophysics Data System (ADS)

We present a novel method to generate ultra-wideband (UWB) monocycle pulses using polarization state rotation filtering of optical negative pulses. Monocycle-like optical pulses with reversed polarities can be generated with appropriate polarization adjustment.

Jiang, Huan; Wen, He; Zheng, Xiaoping; Zhang, Hanyi; Guo, Yili

2008-11-01

66

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

67

Cross-layer functionality in ultra-wideband applications, The EUWB perspective  

Microsoft Academic Search

EUWB (Coexisting Short Range Radio by Advanced Ultra-Wideband Radio Technology, FP7-ICT-215669, www.euwb.eu) has been an industry-led initiative of twenty-one major industrial and excellent academic organizations from Europe and Israel targeting innovative improvement, adaptation, integration and application of short-range Ultra-Wideband Radio Technology (UWB-RT). EUWB will effectively leverage and significantly enhance the scientific knowledge base in the advanced UWB-RT and will provide

Christian KOCKS; Alexander VIESSMANN; Shangbo Wang; Ernest SCHEIBER; Dong Xu; Guido H. BRUCK; Peter JUNG; S. Zeisberg

2009-01-01

68

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

69

An adaptive Orthogonaly Division Multiplexing baseband modem for wideband wireless communication  

E-print Network

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

Tan, Jit Ken

2006-01-01

70

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

SciTech Connect

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 few tens of kilovolts to 250-kV. EMBL (EnantioMorphic Blumlein) is a similar device (presently under development) which uses a gas switch to short the falling portion of a 2-nS pulse to approximately 100-pS. To date, an output voltage of approximately 600-kV has been obtained (700-kV is the design goal). Depending upon the source, repetitive operation from single shot to 5-kHz (1-kHz nominal) has been obtained with excellent reliability and repeatability. Both sources are plasma switched impulse transmitters using a Hydrogen-thyratron based modulator, an oil-filled Blumlein (of two types), a peaking (or shorting) switch and a wideband TEM horn. Powers exceeding one-gigawatt are routinely generated. This technology appears to be extendable to at least 10-gigawatts. The frequency spectrum of the radiated pulse from these sources include the spectrum of 100-MHz to 3-GHz. The pulse is generated externally and then injected into the antenna. Due to the high powers involved and the need to radiate a broad spectrum of frequencies, Sandia has concentrated on TEM horn antennas. Several TEM horns have been built and used during this program. In those cases where higher gains are desired for the higher frequencies, TEM horn-fed dish antennas have been employed. A detailed overview of the UWB Transmitters along with measured radiated electric field strengths will be presented.

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

1992-01-01

71

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

SciTech Connect

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 few tens of kilovolts to 250-kV. EMBL (EnantioMorphic Blumlein) is a similar device (presently under development) which uses a gas switch to short the falling portion of a 2-nS pulse to approximately 100-pS. To date, an output voltage of approximately 600-kV has been obtained (700-kV is the design goal). Depending upon the source, repetitive operation from single shot to 5-kHz (1-kHz nominal) has been obtained with excellent reliability and repeatability. Both sources are plasma switched impulse transmitters using a Hydrogen-thyratron based modulator, an oil-filled Blumlein (of two types), a peaking (or shorting) switch and a wideband TEM horn. Powers exceeding one-gigawatt are routinely generated. This technology appears to be extendable to at least 10-gigawatts. The frequency spectrum of the radiated pulse from these sources include the spectrum of 100-MHz to 3-GHz. The pulse is generated externally and then injected into the antenna. Due to the high powers involved and the need to radiate a broad spectrum of frequencies, Sandia has concentrated on TEM horn antennas. Several TEM horns have been built and used during this program. In those cases where higher gains are desired for the higher frequencies, TEM horn-fed dish antennas have been employed. A detailed overview of the UWB Transmitters along with measured radiated electric field strengths will be presented.

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

1992-09-01

72

Ultra-Wideband Angle-of-Arrival Tracking Systems  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

73

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

2008-04-01

74

Ultra wideband ground penetrating radar imaging of heterogeneous solids  

DOEpatents

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

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

1998-01-01

75

Ultra wideband ground penetrating radar imaging of heterogeneous solids  

DOEpatents

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

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

1998-11-10

76

Signal processing techniques for stepped frequency ultra-wideband radar  

NASA Astrophysics Data System (ADS)

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

Nguyen, Lam

2014-05-01

77

Optimal Waveforms Design for Ultra-Wideband Impulse Radio Sensors  

PubMed Central

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

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

2010-01-01

78

Optimal waveforms design for ultra-wideband impulse radio sensors.  

PubMed

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

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

2010-01-01

79

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

Microsoft Academic Search

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

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

2005-01-01

80

Matching layer for path loss reduction in ultra wideband implant communications.  

PubMed

Real-time monitoring of various physiological signals is of utmost importance for the treatment of chronic conditions. Radio technology can enable real-time sensing and collection of physiological data to facilitate timely medication and early pre-hospital management of patients. This can be realized with the aid of implantable biomedical sensors with the capability to transmit wirelessly the collected information to an external unit for display and analysis. Currently, commercial wireless medical implantable sensors operate in frequencies below 1 GHz with narrowband signals. Recently, it has been demonstrated that ultra wideband (UWB) signals could be also used for the radio interface of these devices. However, establishing an implant communication link in the allocated UWB spectrum of 3.1-10.6 GHz is challenging. The attenuation of UWB signals propagating through biological tissues at these frequencies is high. Part of these path losses are caused by the impedance mismatch between the two propagation environments (i.e., air and biological tissues) that constitute an implant communication link. This mismatch results in inefficient power transmission of the radio waves. In this paper we propose the use of a layer of dielectric material that can be applied on the patient's skin. The permittivity value of this matching layer has to be chosen such that wave coupling is maximized. Through numerical simulations we determined the appropriate permittivity value of a matching layer for UWB implant communication links in the human thorax for 1-6 GHz. Path loss reduction of up to 10 dB can be obtained in this frequency band. These results can help improve the use of UWB signals for other in-body biomedical devices like the wireless capsule endoscope (WCE). PMID:25571604

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

2014-08-01

81

Reconfigurable Wideband Circularly Polarized Microstrip Patch Antenna for Wireless Applications  

NASA Astrophysics Data System (ADS)

In this thesis, developments of rectangular microstrip patch antenna to have circular polarization agility with wideband performance, for wireless applications are presented. First, a new technique to achieve circularly polarized (CP) probe feed single-layer microstrip patch antenna with wideband characteristics is proposed. The antenna is a modified form of the popular E-shaped patch, used to broaden the impedance bandwidth of a basic rectangular patch antenna. This is established by letting the two parallel slots of the E-patch unequal. Thus, by introducing asymmetry two orthogonal currents on the patch are excited and circularly polarized fields are realized. The proposed technique exhibits the advantage of the simplicity inherent in the E-shaped patch design. It requires only slot lengths, widths, and position parameters to be determined. Also, it is suitable for later adding the reconfigurable capability. With the aid of full-wave simulator Ansoft HFSS, investigations on the effect of various dimensions of the antenna have been carried out via parametric analysis. Based on these investigations, a design procedure for a CP E-shaped patch is summarized. Various design examples with different substrate thicknesses and material types are presented and compared, with CP U-slot patch antennas, recently proposed in the literature. A prototype has been constructed following the suggested design procedure to cover the IEEE 802.11b/g WLAN band. The performance of the fabricated antenna was measured and compared with the simulation results for the reflection coefficient, axial ratio, radiation pattern, and antenna gain. Good agreement is achieved between simulation and measured results demonstrating a high gain and wideband performance. Second, a polarization reconfigurable single feed E-shaped patch antenna with wideband performance is proposed. The antenna is capable of switching from right-hand circular polarization (RHCP) to left-hand circular polarization (LHCP) and vice versa, with the aid of two RF PIN diodes that act as RF switches. The proposed structure which is simple; consists of a single-layer single fed radiating E-shaped patch and RF switch placed on each of its slots at an appropriate location. The design targets WLAN IEEE 802.11b/g frequency band (2.4- 2.5 GHz) as one example of the wireless applications. The idea is based on the first proposed design. In other words, if one of the switches is ON and the other is OFF, the two slot lengths will become effectively unequal and circular polarization will be obtained. If the states of the two switches are reversed, circular polarization with opposite orientation will be obtained at the same frequency band. Full-wave simulator Ansoft HFSS is again used for the analysis. Complete detailed DC biasing circuit of the switches for integration with the antenna is presented. Also, characterizations of the microwave components used in the biasing circuit are discussed. Antenna prototype has been fabricated and tested. Simulation results along with the measured one, for the reflection coefficient, axial ratio, radiation pattern, and antenna gain agree well, showing wide bandwidth and high gain for the two circularly polarized modes.

Khidre, Ahmed

82

Ultra-Wideband Optical Modulation Spectrometer (OMS) Development  

NASA Technical Reports Server (NTRS)

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

Gardner, Jonathan (Technical Monitor); Tolls, Volker

2004-01-01

83

Ultra-wideband polarization conversion metasurfaces based on multiple plasmon resonances  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

84

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

PubMed

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

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

2013-03-01

85

Photonic monocycle pulse generation and modulation for ultra-wideband-over-fiber application  

NASA Astrophysics Data System (ADS)

In order to integrate local ultra-wideband (UWB) environment into fixed wired networks or wireless wide-area infrastructures and eliminate the high cost of microwave electrical circuits or devices, UWB-over-fiber systems have emerged to exploit the advantages offered by optical fiber. We experimentally demonstrate a photonic UWB monocycle pulse generation and pulse position modulation (PPM). The UWB monocycle pulse with inverse polarity can be generated based on the two differently-biased Mach-Zehnder modulators, subsequently the PPM of the UWB monocycle pulse is realized through the nonlinear polarization rotation (NPR) arising in a semiconductor optical amplifier (SOA). We proposed and experimentally demonstrated an effective procedure to generate and maintain a linear output state of polarization (SOP) during the course of the nonlinear polarization rotation (NPR) of an SOA. High performance of polarization switching can be achieved. The proposed scheme is more preferable for the UWB-over-fiber applications due to its compact size and high stability.

Fu, Songnian; Zhong, Wen-De; Shum, P.; Li, Jianqiang; Xu, Kun

2008-11-01

86

Fully integrated microwave reflectometers in multi-layer microstrip-slot technology for ultra wideband applications  

Microsoft Academic Search

This paper presents the design of compact fully integrated six-port reflectometers, which, from scalar power measurements, are capable to determine the complex reflection coefficient over an ultra wide frequency band of 3.1 to 10.6 GHz. These devices are formed by multi-layer microstrip\\/slot couplers and power dividers that are assembled without vias or wire cross-overs. An ultra wideband operation of these

M. E. Bialkowski; N. Seman; M. S. Leong; S. P. Yeo

2008-01-01

87

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

Microsoft Academic Search

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

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

2009-01-01

88

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

E-print Network

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

Arslan, Hüseyin

89

Investigation on ultra-wideband printed circular monopole antenna with frequency-notched  

Microsoft Academic Search

This paper presents a novel design of a printed circular monopole antenna for ultra-wideband applications. It consists of a circular patch with an arc slot notched, which intends to obtain frequency notched for WLAN. To broaden the bandwidth and shorten the width of the substrate, a truncated ground plane is introduced. Thus, the width of the substrate is sharply shortened

Zhantao Yang; Li Li; Huazhi Wang

2008-01-01

90

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

E-print Network

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

Ha, Dong S.

91

Low Complexity Chirp Pulsed Ultra-Wideband System with Near-Optimum Multipath Performance  

Microsoft Academic Search

This paper describes the Impulse Radio Ultra- Wideband (IR-UWB) system using linear chirp UWB pulses as symbols. The novel method of coherent or differentially coherent detection of chirp pulses in multipath channels is introduced. The method divides detection in the receiver between its analog and digital part; in the analog part of the receiver, received signal is compressed in frequency

Igor Dotlic; Ryuji Kohno

2011-01-01

92

Fingerprinting Localization based on Neural Networks and Ultra-wideband signals  

E-print Network

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

Paris-Sud XI, Université de

93

An ultra-wideband radar for vehicle detection in railroad crossings  

Microsoft Academic Search

This paper describes an ultra-wideband (UWB) radar system designed to detect motor vehicles such as cars and trucks when they are present in a railway crossing. Once fully developed, the detection performance of the system is to be compared against a video detection system in a test at a crossing in Maywood, Illinois. If the test is successful this system

Stephen P. Lohmeier; R. Rajaraman; V. C. Ramasami

2002-01-01

94

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

E-print Network

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

Tentzeris, Manos

95

Low-loss ultra-wideband (UWB) filters using suspended stripline  

Microsoft Academic Search

Two types of suspended stripline ultra-wideband bandpass filters are described, one based on a standard lumped element (L-C) filter concept including transmission zeroes to improve the upper passband slope, and a second one consisting of the combination of a low-pass and a high-pass filter.

Wolfgang Menzel; Mohammad S. Rahman Tito; Lei Zhu

2005-01-01

96

Modulation Schemes Based on Orthogonal Pulses for Time Hopping Ultra Wideband Radio Systems  

Microsoft Academic Search

This paper describes a combined modulation scheme for time hopping ultra wideband (TH-UWB) radio systems using on-off keying (OOK) and pulse shape modulation (PSM). For this scheme, a set of orthogonal pulses is used to represent bits in a symbol. These orthogonal pulses are transmitted simultaneously in the same time slot resulting in a composite pulse. By assigning different subset

Sudhan Majhi; A. S. Madhukumar; A. Benjamin Premkumar; Francois P. S. Chin

2007-01-01

97

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

PubMed

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

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

2014-08-01

98

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

E-print Network

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

Kansas, University of

99

A New Type of Miniature Ultra-Wideband Band-Pass Filter with Coplanar Waveguide Fed  

NASA Astrophysics Data System (ADS)

A novel miniature ultra-wideband (UWB) bandpass filter with coplanar waveguide (CPW) fed is proposed. The size of the filter is reduced largely because of combining the wideband couple gap and parallel-coupled CPW line (not cascading multiple resonator), and the length of realized filter is only 0.42 ? g0 (? g0 is the guiding wavelength at central frequency). The measured insertion loss is less than 2.0 dB, and the group delay variation is less than 0.2 ns within the UWB passband. Basic agreement between the simulated and measured results has been achieved.

Yao, Chunhui; Zhang, Wenmei; Han, Liping; Ma, Runbo

2007-10-01

100

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

101

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

E-print Network

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

Park, Seong-Ook

102

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

Microsoft Academic Search

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

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

2007-01-01

103

Ultra wideband antenna array processing under spatial aliasing  

E-print Network

gain of the proposed setup is potentially signiflcant, speciflcally when the transmitters are closely spaced and under low Signal to Noise Ratio (SNR), which makes it applicable to license-free communication. v To My parents, Nayereh and Kazem, my... . . . . . . . . . . . . . . . . . . . 34 V ERROR MAGNITUDES UNDER ALIASING : : : : : : : : : : 38 VI SIMULATION SETUP AND RESULTS : : : : : : : : : : : : : 45 A. MLE-based Simulation . . . . . . . . . . . . . . . . . . . . 45 viii CHAPTER Page B. Wideband Subspace-based Simulation...

Shapoury, Alireza

2009-05-15

104

A Transformer Noise-Canceling Ultra-Wideband CMOS Low-Noise Amplifier  

NASA Astrophysics Data System (ADS)

Previously reported wideband CMOS low-noise amplifiers (LNAs) have difficulty in achieving both wideband input impedance matching and low noise performance at low power consumption and low supply voltage. We present a transformer noise-canceling wideband CMOS LNA based on a common-gate topology. The transformer, composed of the input and shunt-peaking inductors, partly cancels the noise originating from the common-gate transistor and load resistor. The combination of the transformer with an output series inductor provides wideband input impedance matching. The LNA designed for ultra-wideband (UWB) applications is implemented in a 90nm digital CMOS process. It occupies 0.12mm2 and achieves |S11| < -10dB, NF < 4.4dB, and |S21| > 9.3dB across 3.1-10.6GHz with a power consumption of 2.5mW from a 1.0V supply. These results show that the proposed topology is the most suitable for low-power and low-voltage UWB CMOS LNAs.

Kihara, Takao; Matsuoka, Toshimasa; Taniguchi, Kenji

105

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

Microsoft Academic Search

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

Jinghui Qiu; Ying Suo; Wei Li

2007-01-01

106

Ultra-wideband, zero visual signature RF vest antenna for man-portable radios  

Microsoft Academic Search

This paper presents the recent research of the COMbat Wear INtegration (COMWIN) RF vest antenna initially presented at MILCOM2000. This version of the ultra-wideband VHF\\/UHF (30 MHz to 500 MHz) vest antenna, designated as MK-III, is integrated into the existing dismounted marine\\/soldier kevlar flak vest and has no visual signature. This antenna is one of the three COMWIN antennas developed

Jovan E. Lebaric; Richard W. Adler; Matthew E. Limbert

2001-01-01

107

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

108

A Low-Power Ultra-Wideband CMOS True RMS Power Detector  

Microsoft Academic Search

This paper introduces a low-power ultra-wideband true root-mean-square power detector with a 0.13-mum CMOS process operating from 125 MHz to 8.5 GHz. The detector utilizes the MOS transistor's square-law characteristic in the strong inversion region to obtain the power information of the input RF signal, and its exponential characteristic in the weak inversion region to realize the linear-in-decibel output. Measured

Yijun Zhou; Michael Yan-Wah Chia

2008-01-01

109

Photonic Polarity-Switchable Ultra-Wideband Pulse Generation Using a Tunable Sagnac Interferometer Comb Filter  

Microsoft Academic Search

A photonic approach to polarity-switchable ultra-wideband (UWB) pulse generation is proposed. The proposed setup principally consists of an electrooptic phase modulator (EOPM) and a tunable optical comb filter constructed with another EOPM inside a Sagnac interferometer. The comb filter working at its linear region performs the phase-to-intensity conversion to generate UWB pulses with monocycle shape. By adjusting the bias voltage

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

2008-01-01

110

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

111

Photonic ultra-wideband monocycle pulse generation using a single electro-optic modulator  

Microsoft Academic Search

A compact and low-cost approach to photonic ultra-wideband (UWB) monocycle pulse generation is proposed and experimentally demonstrated based on the wavelength dependence of the half-wave voltage of a Mach-Zehnder modulator (MZM). By employing a single MZM and two laser sources at around 1310nm and 1550nm, a pair of polarity-reversed monocycle pulses with the full width at half maximum (FWHM) of

Songnian Fu; Jianqiang Li; P. Shum

2008-01-01

112

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

113

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

DOEpatents

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

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

2011-06-14

114

Non-inertial ultra-wideband acoustic transducers  

NASA Astrophysics Data System (ADS)

In introductory and even some advanced textbooks covering ultrasonic transducers including piezoelectric discs, the transducers used for excitation are normally introduced as electrically driven mechanical oscillators operated reversely for detection. A refined treatment based on original work from the early 60's of the last century demonstrates that even in this simple case, electromagnetic-mechanical coupling is restricted to interfaces with the volume of transducer discs operating in part as inertial mass, which can also be provided by suitable backing with improved results. Geometrical effects in combination with the oscillating masses lead to resonances of the transducers limiting the applications. Thin transducer discs or film transducers, which are in comparison to the oscillating masses in the generated or detected acoustic waves approximately mass free, can be operated such that inertial effects in the transducer are reduced respectively almost avoided. Even though such transducers are available on a commercial basis and are well introduced for the generation and detection of Lamb waves, the basic underlying principles are usually not highlighted. These effects are experimentally demonstrated and compared to expectations based on basic principles. Schemes suitable to overcome bandwidth restrictions given by geometrical effects are discussed and an application of wideband transducers for Lamb waves used for stress detection is exemplified.

Amjad, U.; Hahn, K.; Tang, T. G.; Grill, W.

2009-03-01

115

Ultra-wideband and low-frequency SAR interferometry  

Microsoft Academic Search

The authors analyse different techniques for 3D SAR mapping. Interferometry using narrow-band SAR enables retrieval of topography but gives an ambiguous height. Stereoscopy can also be used but has degraded resolution due to speckle. For ultra-wide band SAR, i.e. wavelength-order resolution, these techniques converge and give similar vertical resolution. A significant advantage, however, is that the interferometric height becomes unambiguous

L. M. H. Ulander; P. O. Frolund

1996-01-01

116

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

E-print Network

Study of Ultra-Wideband Versus Narrowband Microwave Hyperthermia for Breast Cancer Treatment Mark (NB) microwave hyperthermia for breast cancer treatment with a recently proposed ultra-wideband (UWB studies have shown local hyperthermia to be effective in the treatment of a variety of cancers [1

Hagness, Susan C.

117

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

118

Design and development of a small compact ultra wideband antenna  

NASA Astrophysics Data System (ADS)

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

Qurratulain; Chattoraj, Neela

2013-04-01

119

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

120

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

121

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

DOEpatents

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

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

2014-10-07

122

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

PubMed Central

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

Rotaru, Mihai; Sykulski, Jan

2010-01-01

123

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

124

Ultra-Wideband GPR Imaging of the Vaucluse Karst Aquifer  

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

125

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

Microsoft Academic Search

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

Jeong Soo Lee; Cam Nguyen

2001-01-01

126

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.

127

Ultra-wideband sensors for improved magnetic resonance imaging, cardiovascular monitoring and tumour diagnostics.  

PubMed

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

Thiel, Florian; Kosch, Olaf; Seifert, Frank

2010-01-01

128

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

PubMed Central

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

Thiel, Florian; Kosch, Olaf; Seifert, Frank

2010-01-01

129

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

PubMed Central

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

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

2011-01-01

130

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

131

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

132

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

2011-01-01

133

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

134

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

135

On Equalization for Direct Sequence-Ultra Wideband System Using Received Response Code Sequence  

NASA Astrophysics Data System (ADS)

This paper proposes a combination of novel Received Response (RR) sequence at the transmitter and Matched Filter-Equalizer-RAKE (MF-EQZ-RAKE) combining scheme receiver system for Direct Sequence-Ultra Wideband (DS-UWB) multipath channel model. When binary code sequence such as M sequence is used, there is a possibility of generating extra Inter-Symbol Interference (ISI) in the UWB system. Therefore, it is quite a challenging task to collect the energy efficiently although RAKE reception method is applied at the receiver. The main purpose of the proposed system is to overcome the performance degradation for UWB transmission due to the occurrence of Inter-Symbol Interference (ISI) during high speed transmission of ultra short pulses in a multipath channel. The proposed system improves the system performance by improving the RAKE reception performance using RR sequence and suppressing the ISI effect with the equalizer. Simulation results verify that significant improvement can be obtained by the proposed system especially in UWB multipath channel models such as channel CM4 that suffered severe ISI effect.

Toh, Keat Beng; Tachikawa, Shin'ichi

136

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

137

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

138

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

139

Ultra-Wideband Surface Acoustic Wave Devices Using Cu-Grating\\/Rotated-YX-LiNbO3Substrate Structure  

Microsoft Academic Search

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

Ken-ya Hashimoto; Hiroki Asano; Tatsuya Omori; Masatsune Yamaguchi

2004-01-01

140

Low-Cost, High-Capacity Ultra-Long-Haul WDM Systems Based on Wide-Band Raman Amplification  

Microsoft Academic Search

Wide-band Raman amplification offers a low cost soltiton for ultra-long-haul, high-capacity WDM transmission systems by enabling low cost designis for the terminal and line equipment. Results are shown on a 2.4Tbls all-Raman system over 1500km SSMF with standatd NRZ, RS255\\/239 OOB-FEC, and 50GHz channel spacing, using 100nm-bandwidth Raman line amplifiers.

M. W. Chbat; H. A. Fevrier

2002-01-01

141

Design and analysis of new printed wideband antennas for wireless applications  

NASA Astrophysics Data System (ADS)

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

Asirvatham, Koby

142

A technique for the generation of customizable ultra-wideband pseudo-noise waveforms  

NASA Astrophysics Data System (ADS)

Noise excitation sources in radar systems have become increasingly useful in applications requiring wideband spectral responses and covertness. However, in applications requiring spectral controllability, traditional analog noise sources prove troublesome and require additional hardware such as sets of digital filters whose own spectral characteristics must also be accounted for. In an effort to reduce these issues and increase the applications of noise waveforms, a technique for generating a fully controllable pseudo-noise waveform is presented. This pseudo-noise waveform will be generated through the use of a multi-tone waveform. By randomizing the phase angles and setting the appropriate amplitudes to the individual tones, the result is a waveform whose temporal pattern resembles noise and frequency response is broadband. The capabilities of this digitally produced pseudo-noise multi-tone waveform is presented by optimization via a water-filling technique, thereby producing a flat spectral response for a user defined amplitude, effectively removing the spectral effects of the radar components. This optimized waveform is used to present methods for increasing signal to noise ratio (SNR) of cross-correlated responses of the waveform through the application of window functions to the waveform. As a whole, this paper showcases the ability to use this pseudo-noise multi-tone waveform for complete ultra-wideband (UWB) spectral control through water-filling and a method for increasing SNR of the cross correlated response of the transmitted and received radar waveform for a bandwidth of 2.5 GHz ranging from 2 to 4.5 GHz.

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

2011-06-01

143

Orthogonal frequency coded filters for use in ultra-wideband communication systems.  

PubMed

The use of ultra-short pulses, producing very wide bandwidths and low spectral power density, are the widely accepted approach for ultra-wideband (UWB) communication systems. This approach is simple and can be implemented with current digital signal processing technologies. However, surface acoustic wave (SAW) devices have the capability of producing complex signals with wide bandwidths and relatively high frequency operation. This approach, using SAW based correlators, eliminates many of the costly components that are needed in the IF block in the transmitter and receiver, and reduces many of the signal processing requirements. This work presents the development of SAW correlators using orthogonal frequency coding (OFC) for use in UWB spread spectrum communication systems. OFC and pseudonoise (PN) coding provide a means for UWB spreading of data. The use of OFC spectrally spreads a PN sequence beyond that of code division multiple access (CDMA) because of the increased bandwidth providing an improvement in processing gain. The transceiver approach is still very similar to that of a CDMA but provides greater code diversity. Experimental results of a SAW filter designed with OFC transducers are presented. The SAW correlation filter was designed using seven contiguous chip frequencies within the transducer. SAW correlators with a 29% fractional bandwidth were fabricated on lithium niobate (LiNbO3) having a center frequency of 250 MHz. A coupling-of-modes (COM) model is used to predict the SAW filter response experimentally and is compared to the measured data. Good correlation between the predicted COM responses and the measured device data is obtained. Discussion of the design, analysis, and measurements are presented. The experimental matched filter results are shown for the OFC device and are compared to the ideal correlation. The results demonstrate the OFC SAW device concept for UWB communication transceivers. PMID:18407859

Gallagher, Daniel R; Malocha, Donald C; Puccio, Derek; Saldanha, Nancy

2008-03-01

144

ULTRA SECURE HIGH RELIABILITY WIRELESS RADIATION MONITOR  

SciTech Connect

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

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

2011-08-03

145

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

146

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

147

A VLSI Neural Monitoring System With Ultra-Wideband Telemetry for Awake Behaving Subjects.  

PubMed

Long-term monitoring of neuronal activity in awake behaving subjects can provide fundamental information about brain dynamics for neuroscience and neuroengineering applications. Here, we present a miniature, lightweight, and low-power recording system for monitoring neural activity in awake behaving animals. The system integrates two custom designed very-large-scale integrated chips, a neural interface module fabricated in 0.5 ?m complementary metal-oxide semiconductor technology and an ultra-wideband transmitter module fabricated in a 0.5 ?m silicon-on-sapphire (SOS) technology. The system amplifies, filters, digitizes, and transmits 16 channels of neural data at a rate of 1 Mb/s. The entire system, which includes the VLSI circuits, a digital interface board, a battery, and a custom housing, is small and lightweight (24 g) and, thus, can be chronically mounted on small animals. The system consumes 4.8 mA and records continuously for up to 40 h powered by a 3.7-V, 200-mAh rechargeable lithium-ion battery. Experimental benchtop characterizations as well as in vivo multichannel neural recordings from awake behaving rats are presented here. PMID:23851199

Greenwald, E; Mollazadeh, M; Hu, C; Wei Tang; Culurciello, E; Thakor, V

2011-04-01

148

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

PubMed

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

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

2014-03-10

149

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

150

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

2010-01-01

151

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

152

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

153

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. PMID:22163668

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

2010-01-01

154

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

155

Respiration-rate estimation of a moving target using impulse-based ultra wideband radars.  

PubMed

Recently, Ultra-wide band signals have become attractive for their particular advantage of having high spatial resolution and good penetration ability which makes them suitable in medical applications. One of these applications is wireless detection of heart rate and respiration rate. Two hypothesis of static environment and fixed patient are considered in the method presented in previous literatures which are not valid for long term monitoring of ambulant patients. In this article, a new method to detect the respiration rate of a moving target is presented. The first algorithm is applied to the simulated and experimental data for detecting respiration rate of a fixed target. Then, the second algorithm is developed to detect respiration rate of a moving target. The proposed algorithm uses correlation for body movement cancellation, and then detects the respiration rate based on energy in frequency domain. The results of algorithm prove an accuracy of 98.4 and 97% in simulated and experimental data, respectively. PMID:22131095

Sharafi, Azadeh; Baboli, Mehran; Eshghi, Mohammad; Ahmadian, Alireza

2012-03-01

156

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

SciTech Connect

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. ne frequency spectrum of the radiated pulse from these sources include the spectrum of 100-MHz to 3-GHz. Depending upon the source, repetitive operation from single shot to 5-kHz (1-kHz nominal) has been obtained with excellent reliability and repeatability. 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 few tens of kilovolts to 250-kV. EMBL (EnantioMorphic Blumlein) is a similar device (presently under development) which uses a gas switch to sharpen the trailing edge of a 2-nS pulse to approximately 100-pS. To date, an output voltage of approximately 600-kV has been obtained (700- kV is the design goal). Since the frequency spectra are identical between sources with sharpened leading or trailing edges, alternatively, one can use parallel switches to short the pulse at its peak voltage. The pulse is generated externally and then injected into the antenna. Due to the high powers involved and the need to radiate a broad spectrum of frequencies, Sandia has concentrated on TEM horn. antennas with special high voltage feed adapters. Several TEM horns have been built and used during this program. In those cases where higher gains are desired for the higher frequencies, TEM horn-fed, dish antennas have been employed. An overview of the UWB transmitters, including design and operation of the modulators, the PFN`S, the pulse sharpening switches and the antennas will be presented.

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

1992-11-01

157

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

SciTech Connect

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. ne frequency spectrum of the radiated pulse from these sources include the spectrum of 100-MHz to 3-GHz. Depending upon the source, repetitive operation from single shot to 5-kHz (1-kHz nominal) has been obtained with excellent reliability and repeatability. 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 few tens of kilovolts to 250-kV. EMBL (EnantioMorphic Blumlein) is a similar device (presently under development) which uses a gas switch to sharpen the trailing edge of a 2-nS pulse to approximately 100-pS. To date, an output voltage of approximately 600-kV has been obtained (700- kV is the design goal). Since the frequency spectra are identical between sources with sharpened leading or trailing edges, alternatively, one can use parallel switches to short the pulse at its peak voltage. The pulse is generated externally and then injected into the antenna. Due to the high powers involved and the need to radiate a broad spectrum of frequencies, Sandia has concentrated on TEM horn. antennas with special high voltage feed adapters. Several TEM horns have been built and used during this program. In those cases where higher gains are desired for the higher frequencies, TEM horn-fed, dish antennas have been employed. An overview of the UWB transmitters, including design and operation of the modulators, the PFN'S, the pulse sharpening switches and the antennas will be presented.

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

1992-01-01

158

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

NASA Astrophysics Data System (ADS)

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 upon the source, repetitive operation from single shot to 5-kHz (1-kHz nominal) has been obtained with excellent reliability and repeatability. 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 few tens of kilovolts to 250-kV. EMBL (EnantioMorphic Blumlein) is a similar device (presently under development) which uses a gas switch to sharpen the trailing edge of a 2-nS pulse to approximately 100-pS. To date, an output voltage of approximately 600-kV has been obtained (700-kV is the design goal). Since the frequency spectra are identical between sources with sharpened leading or trailing edges, alternatively, one can use parallel switches to short the pulse at its peak voltage. The pulse is generated externally and then injected into the antenna. Due to the high powers involved and the need to radiate a broad spectrum of frequencies, Sandia has concentrated on TEM horn antennas with special high voltage feed adapters. Several TEM horns have been built and used during this program. In those cases where higher gains are desired for the higher frequencies, TEM horn-fed, dish antennas have been employed. An overview of the UWB transmitters, including design and operation of the modulators, the PFN'S, the pulse sharpening switches and the antennas will be presented.

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

159

Adiabatic and fast passage ultra-wideband inversion in pulsed EPR.  

PubMed

We demonstrate that adiabatic and fast passage ultra-wideband (UWB) pulses can achieve inversion over several hundreds of MHz and thus enhance the measurement sensitivity, as shown by two selected experiments. Technically, frequency-swept pulses are generated by a 12 GS/s arbitrary waveform generator and upconverted to X-band frequencies. This pulsed UWB source is utilized as an incoherent channel in an ordinary pulsed EPR spectrometer. We discuss experimental methodologies and modeling techniques to account for the response of the resonator, which can strongly limit the excitation bandwidth of the entire non-linear excitation chain. Aided by these procedures, pulses compensated for bandwidth or variations in group delay reveal enhanced inversion efficiency. The degree of bandwidth compensation is shown to depend critically on the time available for excitation. As a result, we demonstrate optimized inversion recovery and double electron electron resonance (DEER) experiments. First, virtually complete inversion of the nitroxide spectrum with an adiabatic pulse of 128ns length is achieved. Consequently, spectral diffusion between inverted and non-inverted spins is largely suppressed and the observation bandwidth can be increased to increase measurement sensitivity. Second, DEER is performed on a terpyridine-based copper (II) complex with a nitroxide-copper distance of 2.5nm. As previously demonstrated on this complex, when pumping copper spins and observing nitroxide spins, the modulation depth is severely limited by the excitation bandwidth of the pump pulse. By using fast passage UWB pulses with a maximum length of 64ns, we achieve up to threefold enhancement of the modulation depth. Associated artifacts in distance distributions when increasing the bandwidth of the pump pulse are shown to be small. PMID:23434533

Doll, Andrin; Pribitzer, Stephan; Tschaggelar, René; Jeschke, Gunnar

2013-05-01

160

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

161

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

162

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

2013-07-01

163

Ultra-High Temperature Distributed Wireless Sensors  

SciTech Connect

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

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

2013-03-31

164

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.

165

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

NASA Astrophysics Data System (ADS)

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

Jain, Vipul

166

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

E-print Network

ULTRA WIDEBAND INTERFERENCE EFFECTS ON AN AMATEUR RADIO RECEIVER R. D. Wilson, R. D. Weaver, M of an amateur radio receiver in the presence of sinusoidal and UWB interference is stud- ied. We characterize will have on systems with which spectrum is shared. Radio amateurs are one of the groups concerned

Southern California, University of

167

Abstract--Design of a fully differential sixth order GHz range gm-C lowpass filter for DS-CDMA UWB (ultra wideband)  

E-print Network

(ultra wideband) transceivers is presented. The filter is composed of three identical cascaded biquad parameters are highly sensitive to process variations. Switched capacitor filter implementations are popular-amps with bandwidth in the range of tens of GHz. Transconductor capacitor (gm-C) filters are well suited

Ha, Dong S.

168

Small and Broadband Planar Antennas for UWB Wireless Communication Applications  

NASA Astrophysics Data System (ADS)

Due to the unique features of ultra-wideband (UWB) wireless communication systems, the antenna design with small size and broad band-widths for transfer response and systems gain are required. A novel rolled planar antenna is proposed to meet the requirements for omni-directional UWB wireless communication applications.

Chen, Z. N.

169

Small and Broadband Planar Antennas for UWB Wireless Communication Applications  

Microsoft Academic Search

Due to the unique features of ultra-wideband (UWB) wireless communication systems, the antenna design with small size and broad band-widths for transfer response and systems gain are required. A novel rolled planar antenna is proposed to meet the requirements for omni-directional UWB wireless communication applications.

Z. N. Chen

2007-01-01

170

Performance evaluation of distributed compressed wideband sensing for cognitive radio networks  

Microsoft Academic Search

In emerging cognitive radio (CR) networks, the first cognitive task preceding any dynamic spectrum management is the sensing and identification of spectrum holes in wireless environments. This paper develops a distributed compressed spectrum sensing approach for (ultra-)wideband CR networks. First, compressive sampling is performed at local CRs to scan the very wide spectrum at practical signal-acquisition complexity. Then, measurements or

Zhiz Tian; Erik Blasch; Wenhua Li; Genshe Chen; Xiaokun Li

2008-01-01

171

Coplanar Printed-Circuit Antenna With Band-Rejection Elements For Ultra-Wideband Filtenna Applications  

E-print Network

Introduction Filtennas consist of wideband antenna structures, which incorporate narrowband filter elements) technology in the 3.1 - 10.6 GHz range, it is essential that certain narrowband services be appropriately. This paper presents three coplanar filtenna designs, which incorporate, first, a coplanar filter in the feed

Bornemann, Jens

172

Generation of ultra-wideband triplet pulses based on four-wave mixing and phase-to-intensity modulation conversion.  

PubMed

We propose and demonstrate a novel scheme to generate ultra-wideband (UWB) triplet pulses based on four-wave mixing and phase-to-intensity modulation conversion. First a phase-modulated Gaussian doublet pulse is generated by four-wave mixing in a highly nonlinear fiber. Then an UWB triplet pulse is generated by generating the first-order derivative of the phase-modulated Gaussian doublet pulse using an optical filter serving as a frequency discriminator. By locating the optical signal at the linear slope of the optical filter, the phase modulated Gaussian doublet pulse is converted to an intensity-modulated UWB triplet pulse which well satisfies the Federal Communications Commission spectral mask requirements, even in the extremely power-restricted global positioning system band. PMID:23037074

Li, Wei; Wang, Li Xian; Hofmann, Werner; Zhu, Ning Hua; Bimberg, Dieter

2012-08-27

173

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

174

A method of optical ultra-wideband doublet pulse generation based on SOA-XGM and SOA-SGS  

NASA Astrophysics Data System (ADS)

Photonic generation of ultra-wideband (UWB) pulse technology is the key technology of UWB-over-fiber system. The effect of nonlinearity in semiconductor optical amplifier (SOA) is widely applied in the area of all-optical signal processing. A method is proposed to generate UWB doublet pulse using cross-gain modulation (XGM) of SOA and self gain-saturation (SGS) effect of SOA. In this method, the UWB monocycle pulse is generated by SOA-XGM, and the UWB doublet pulse is generated by utilizing the generated UWB monocycle pulse and gain saturation effect of another SOA. According to the proposed method, we obtained the UWB doublet pulse by utilizing photonic simulation software. The center frequency is 4.85GHz and the fraction bandwidth is 122%, it meets the criterion of FCC.

Chen, Xin; Guan, Yalin; Chen, Xinqiao; Yang, Xiaoxue

2013-03-01

175

Photonic generation of ultra-wideband doublet pulse using a semiconductor-optical-amplifier based polarization-diversified loop.  

PubMed

We propose and demonstrate a novel scheme of ultra-wideband (UWB) doublet pulse generation using a semiconductor optical amplifier (SOA) based polarization-diversified loop (PDL) without any assistant light. In our scheme, the incoming gaussian pulse is split into two parts by the PDL, and each of them is intensity modulated by the other due to cross-gain modulation (XGM) in the SOA. Then, both parts are recombined with incoherent summation to form a UWB doublet pulse. Bi-polar UWB doublet pulse generation is demonstrated using an inverted gaussian pulse injection. Moreover, pulse amplitude modulation of UWB doublet is also experimentally demonstrated. Our scheme shows some advantages, such as simple implementation without assistant light and single optical carrier operation with good fiber dispersion tolerance. PMID:22739860

Luo, Bowen; Dong, Jianji; Yu, Yuan; Yang, Ting; Zhang, Xinliang

2012-06-15

176

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

177

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

178

A 60 GHz MMIC pHEMT image reject mixer with integrated ultra wideband IF hybrid and 30 dB of image rejection ratio  

Microsoft Academic Search

A 60 GHz image reject mixer (IRM) with an integrated ultra wideband IF hybrid has been designed, fabricated and characterized in a commercial pHEMT MMIC process. A measured conversion loss (Lc) of 10.2 to 11.4 dB over the frequency range 55 to 65 GHz is obtained with a state-of-the-art image rejection ratio (IRR) of 30 dB at the 60 GHz

Sten E. Gunnarsson; Dan Kuylenstierna; Herbert Zirath

2005-01-01

179

Design of a wideband antenna package with a compact spatial notch filter for wireless applications  

Microsoft Academic Search

This paper describes a compact package, comprising a wideband antenna with a compact spatial notch filter, useful for RF applications requiring a high rate of data transfer. The use of fractal concepts helps to reduce the package to almost half the normal size, and to realize a much sharper band-stop than would be possible with a conventional filter. The antenna

Judo Yeo; R. Mittra

2002-01-01

180

Adaptive and Ultra-Wideband Sampling via Signal Segmentation and Projection  

E-print Network

functionsfk are not band- limited. We discuss this in section 3.) For this choice of N, we compute f(t) = kZ f(t)[(k)Tc,(k@arl.army.mil Abstract: Adaptive frequency band (AFB) and ultra-wide-band (UWB) systems require either rapidly changing frequency band (AFB) and ultra-wide-band (UWB) systems, requiring either rapidly changing or very high

Boyer, Edmond

181

Ultra-Wideband Bandpass Filter with Sharp Attenuation Slope Using Inter-Digital Finger Resonator and Parallel-Coupled Lines  

NASA Astrophysics Data System (ADS)

This paper presents an ultra-wideband (UWB) bandpass filter (BPF) with sharp attenuation slope characteristics. The circuit structure consists of an inter-digital finger resonator, parallel-coupled lines and phase matching line. The design of the bandwidth was described by using the even and odd mode characteristic impedances in the resonator structure. The parallel-coupled lines were also designed in the same manner. The parameters of the resonator and two parallel-coupled lines in combination as the BPF were then optimized by the simulation with HFSS. The designed BPF was experimentally fabricated and its measured performances showed the bandwidth from 3.6 to 10GHz with the 20dB outband rejection. For the U.S. UWB band design, the matching line was inserted between the two parallel-coupled lines. The matching at both band edges was then qualitatively analyzed on the smithchart. The HFSS simulation results of the structure realized the bandwidth from 3.1 to 10.6GHz with sharp attenuation slope characteristics for SWR < 2.0. The measurement results agree well with the simulation results.

Yasuzumi, Takenori; Omote, Yusuke; Uwano, Tomoki; Hashimoto, Osamu

182

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

PubMed

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 flasks containing cell culture media are placed inside the GTEM cell, the uniform fields of the empty GTEM cell are significantly perturbed. The fields inside the cell culture medium, representing the fields to which the biological cells are exposed, are no longer monopolar and are spatially highly nonuniform. These effects result from a combination of refraction and distortion of the incident wave, combined with excitation of resonant eigenmodes within the cell culture medium volume. The simulations show that these distortions of the incident waveform may be mitigated by supporting the sample on a high permittivity pedestal and modifying the incident waveform to more closely approximate a Gaussian pulse. Under all simulated conditions, the estimated maximum temperature rises are completely negligible, ensuring that any experimentally observed unusual cell function or histopathology can be associated with nonthermal effects. PMID:16686400

Ji, Zhen; Hagness, Susan C; Booske, John H; Mathur, Satnam; Meltz, Martin L

2006-05-01

183

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

SciTech Connect

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

Nekoogar, F; Dowla, F

2007-06-06

184

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

PubMed

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

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

2013-10-01

185

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

PubMed Central

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

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

2005-01-01

186

Through-the-wall localization of a moving target by two independent ultra wideband (UWB) radar systems.  

PubMed

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

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

2013-01-01

187

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

PubMed Central

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

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

2013-01-01

188

Ultra wide-band slot antenna based on liquid crystal polymer material for millimeter wave application  

Microsoft Academic Search

A millimeter wave ultra-wide band (UWB) tapered slot antenna is presented based on a multilayer liquid crystal polymer (LCP) circuit process. The multilayer circuit board consists of eight copper layers and seven LCP layers. In order to enhancing the bandwidth, two overlapped tapered slots with different flare angle are applied in the 3rd and the 5th copper layers, respectively. A

Dapeng Jin; Shaoqiu Xiao; Shanshan Gao; Mingchun Tang; Bing-zhong Wang

2010-01-01

189

Detection and Interference Suppression for Ultra-Wideband Signaling with Analog Processing  

E-print Network

to quantization in the presence of strong narrowband interference is significant. This motivates our design amplifiergain. This front end, follow,edby either a matched filter or one bit AID, yields acceptable performance even with strong narrowband interference. 1. INTRODUCTION There is growing interest in commercial ultra

Dabeer, Onkar

190

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

NASA Technical Reports Server (NTRS)

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

Tolls, Volker; Stringfellow, Guy (Technical Monitor)

2001-01-01

191

Novel Compact Ultra-Wideband Bandpass Filter by Application of Short-Circuited Stubs and Stepped-Impedance-Resonator  

NASA Astrophysics Data System (ADS)

To realize the compact ultra-wideband (UWB) bandpass filters, a novel filter prototype with two short-circuited stubs loaded at both sides of a stepped-impedance resonator (SIR) via the parallel coupled lines is proposed based on a distributed filter synthesis theory. The equivalent circuit of this filter is established, while the corresponding 7-pole Chebyshev-type transfer function is derived for filter synthesis. Then, a distributed-circuit-based technique was presented to synthesize the elements' values of this filter. As an example, a FCC UWB filter with the fractional bandwidth (FWB) @ -10dB up to 110% was designed using the proposed prototype and then re-modeled by commercial microwave circuit simulator to verify the correctness and accuracy of the synthesis theory. Furthermore, in terms of EM simulator, the filter was further-optimized and experimentally-realized by using microstrip line. Good agreements between the measurement results and theoretical ones validate the effectiveness of our technique. In addition, compared with the conventional SIR-type UWB filter without short-circuited stubs, the new one significantly improves the selectivity and out-of-band characteristics (especially in lower one -45dB@1-2GHz) to satisfy the FCC's spectrum mask. The designed filter also exhibits very compact size, quite low insertion loss, steep skirts, flat group delay and the easily-fabricatable structure (the coupling gap dimension in this filter is 0.15mm) as well. Moreover, it should be noted that, in terms of the presented design technique, the proposed filter prototype can be also used to easily realize the UWB filters with other FBW even greater than 110%.

Chen, Chun-Ping; Ma, Zhewang; Anada, Tetsuo

192

Design and simulation of gain-flattened ultra wideband fiber amplifiers covering S-, C-, and L-bands  

NASA Astrophysics Data System (ADS)

A novel design of a gain-flattened amplifier that covers an ultra-wideband including the S-, C-, and L-bands is presented. The amplifier is comprised of a split-band structure, which amplifies the S-, C-, and L-band signals in separate paths then recombines the amplified signals for the final output to the transmission fiber. For C-band amplification, a two-stage erbium doped fiber amplifier (EDFA) with mid-stage gain equalization filter (GEF) topology was used, for L-band amplification, single-stage longer EDFA topology was used. While for S-band amplification, a Raman fiber amplifier (RFA) with counter-propagating multiple-pump configuration was adopted. Using the VPIcomponentMaker(TM) software package from VPI Systems(TM), the design was simulated and tested for optimization. Computer simulations analyzed the gain and noise-figure of the novel amplifier. Approximately 30-dB gain with an overall gain ripple less than 1.6 dB and low noise-figure, and gain-bandwidth over 120 nm can be achieved. It encompasses more than 144 ITU-T channels at 100 GHz spacing. Comparing with previous reported work in the literature, the amplification range of the novel fiber amplifier not only covers the C- and L-bands, but also covers the S-band, which is the first investigation of this type. And hasn't been reported in literature by others for discrete amplification. This makes the novel amplifier described here as having the widest gain-flattened amplification bandwidth range among the discrete fiber amplifiers investigated till today.

Cao, Yang

193

Penetration and propagation into biological matter and biological effects of high-power ultra-wideband pulses: a review.  

PubMed

Abstract Systems emitting ultra-wideband high power microwave (HP/UWB) pulses are developed for military and civilian applications. HP/UWB pulses typically have durations on the order of nanoseconds, rise times of picoseconds and amplitudes around 100?kV?m(-1). This article reviews current research on biological effects from HP/UWB exposure. The different references were classified according to endpoints (cardiovascular system, central nervous system, behavior, genotoxicity, teratology?…). The article also reviews the aspects of mechanisms of interactions and tissue damage as well as the numerical work that has been done for studying HP/UWB pulse propagation and pulse energy deposition inside biological tissues. The mechanisms proposed are the molecular conformation change, the modification of chemical reaction rates, membrane excitation and breakdown and direct electrical forces on cells or cell constituents, and the energy deposition. As regards the penetration of biological matter and the deposited energy, mainly computations were published. They have shown that the EM field inside the biological matter is strongly modified compared to the incident EM field and that the energy absorption for HP/UWB pulses occurs in the same way as for continuous waves. However, the energy carried by a HP/UWB pulse is very low and the deposited energy is low. The number of published studies dealing with the biological effects is small and only a few pointed out slight effects. It should be further noted that the animal populations used in the studies were not always large, the statistical analyses not always relevant and the teams involved in this research rather limited in number. PMID:25356665

Schunck, Thérèse; Bieth, François; Pinguet, Sylvain; Delmote, Philippe

2014-10-30

194

Adaptive signal processing algorithm for remote detection of heart rate (HR) using ultra-wideband waveforms based on principal component analysis.  

PubMed

Ultra-Wideband (UWB) technology provides a convenient approach for remote biomedical sensing and vital signs monitoring in humans. In this paper, a specific algorithm is proposed to improve the ability of Heart Rate (HR) detection. Unlike previous methods for remote HR detection, the proposed method provides an adaptive filter based on respiration and heart rate parameters obtained from UWB waveforms. The algorithm is capable of detecting heart rate by changing the adaptive filter parameters accordingly. The proposed method is employed on real life data collected by UWB transceiver. According to experiments, it is concluded that the proposed technique is able to handle remote detection of different heart rates accurately. PMID:19963914

Sharifahmadian, Ershad; Ahmadian, Alireza

2009-01-01

195

Photonic generation of ultra-wideband signals by direct current modulation on SOA section of an SOA-integrated SGDBR laser.  

PubMed

Photonic ultra-wideband (UWB) pulses are generated by direct current modulation of a semiconductor optical amplifier (SOA) section of an SOA-integrated sampled grating distributed Bragg reflector (SGDBR) laser. Modulation responses of the SOA section of the laser are first simulated with a microwave equivalent circuit model. Simulated results show a resonance behavior indicating the possibility to generate UWB signals with complex shapes in the time domain. The UWB pulse generation is then experimentally demonstrated for different selected wavelength channels with an SOA-integrated SGDBR laser. PMID:20389743

Lv, Hui; Yu, Yonglin; Shu, Tan; Huang, Dexiu; Jiang, Shan; Barry, Liam P

2010-03-29

196

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

197

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

DOEpatents

A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control. 14 figs.

McEwan, T.E.

1998-05-26

198

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

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1998-05-26

199

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

PubMed

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

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

2014-11-01

200

Advantages and problems of wideband radar  

Microsoft Academic Search

The paper addresses the definition, properties and modeling requirements of wideband and ultra-wideband radars. It begins by establishing the criteria by which the designation 'wideband' might be specified, since the common definition based purely on relative bandwidth fails to invoke some important associations. Next, the role of simulation is discussed and a representative simulation environment is described. The advantages and

Y. D. Shirman; S. P. Leshchenko; V. M. Orlenko

2003-01-01

201

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

E-print Network

An Ultra-Low-Power Power Management IC for Wireless Sensor Nodes Michael D. Seeman, Seth R. Sanders- capacitor converters with size-optimized devices and level-shifting gate drivers. A synchronous rectifier are in section VI. Two switched-capacitor power converters convert the battery voltage, nominally 1.2 V, to 2.1 V

Sanders, Seth

202

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

E-print Network

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

Sanders, Seth

203

AN ULTRA-LOW POWER AND DISTRIBUTED ACCESS PROTOCOL FOR BROADBAND WIRELESS SENSOR NETWORKS  

Microsoft Academic Search

An ultra-low power access control scheme has been proposed for broadband wireless sensor networks. This is a distributed method, which does not require the existence of a central base station, eliminating the possibility of a single point failure. This access protocol combines the best of simple carrier sense multiple access (CSMA) and spread spectrum techniques. It trades the bandwidth in

Lizhi Charlie Zhong; Rahul Shah; Chunlong Guo; Jan Rabaey

2001-01-01

204

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

205

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

PubMed

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

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

2011-01-01

206

Ultra-wideband all-fiber tunable Tm/Ho-co-doped laser at 2 ?m.  

PubMed

We demonstrate an all-fiber tunable Tm/Ho-codoped laser operating in the 2 ?m wavelength region. The wavelength tuning range of the Tm/Ho-codoped fiber laser (THFL) with 1-m length of Tm/Ho-codoped fiber (THDF) was from 1727 nm to 2030 nm. Efficient short wavelength operation and ultra-wide wavelength tuning range of 303 nm were both achieved. To the best of our knowledge, this is the broadest tuning range that has been reported for an all-fiber rare-earth-doped laser to date. By increasing the THDF length to 2 m, the obtainable wavelength of the THFL was further red-shifted to the range from 1768 nm to 2071 nm. The output power of the THFL was scaled up from 1810 nm to 2010 nm by using a stage of Tm/Ho-codoped fiber amplifier (THFA), which exhibited the maximum slope efficiency of 42.6% with output power of 408 mW at 1910 nm. PMID:25401631

Xue, Guanghui; Zhang, Bin; Yin, Ke; Yang, Weiqiang; Hou, Jing

2014-10-20

207

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

208

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

Microsoft Academic Search

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

Theordore Rappaport

2007-01-01

209

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

PubMed

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

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

2014-03-01

210

Millimeter-Wave Ultra-Wideband Bandpass Filter Employing Dual-Mode Ring Resonators Fed by Step-Impedance Coupled Lines  

NASA Astrophysics Data System (ADS)

This paper presents a novel millimeter-wave ultra-wideband (UWB) bandpass filter (BPF) based on microstrip dual-mode rectangular ring resonators. In order to get strong coupling between the input/output line and the dual-mode ring resonators, a step-impedance parallel-coupled structure is adopted for the design of the filter. On the other hand, transmission zeros are produced by the dual-mode resonator. As a consequence, the filter has low insertion-loss in its passband, sharp attenuation in its lower and upper stopbands and very wide stopbands. As an example, a filter with two dual-mode ring resonators is designed and fabricated. The measured frequency property of the fabricated filter shows good agreement with the simulated response.

Cai, Peng; Ma, Zhewang; Kanzaki, Hitoshi; Zhang, Yong; Chen, Bin

2009-05-01

211

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

212

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

213

Software defined radio channel simulator for wireless communications: Demonstrations of the hardware reconfiguration using DSRC and UWB channels  

Microsoft Academic Search

The software defined radio (SDR) channel simulator is designed and implemented in the FPGA for various wireless communication systems. The dedicated short range communications (DSRC) and ultra-wideband (UWB) channels are carried out to observe the characteristics of multi-path fading channels and validate the correctness of the SDR channel simulator. The hardware reconfiguration of the fading channel weighting generator circuit module

Jeich Mar; Chi-Cheng Kuo; You-Rong Lin; Ti-Han Lung

2009-01-01

214

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

NASA Astrophysics Data System (ADS)

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

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

2008-10-01

215

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

216

Improved resolution and reduced clutter in ultra-wideband microwave imaging using cross-correlated back projection: experimental and numerical results.  

PubMed

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

Jacobsen, S; Birkelund, Y

2010-01-01

217

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

218

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

PubMed Central

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

Jacobsen, S.; Birkelund, Y.

2010-01-01

219

Performance analysis of multi-user UWB wireless communication systems  

Microsoft Academic Search

This paper presents a performance comparison of impulse radio ultra wideband (IR-UWB) and multi-band orthogonal frequency division multiplexing (MB-OFDM) for multi-user wireless communication systems. Focusing on the analysis of system performance affected by multi-user interference (MUI) over general additive white Gaussion noise (AWGN) channel, we run a complete system simulation for direct sequence pulse amplitude modulation (DS-PAM), time hopping pulse

Yuhong Li; Youzheng Wang; Jianhua Lu

2009-01-01

220

A Synchronization Design for UWB-Based Wireless Multimedia Systems  

Microsoft Academic Search

Multi-band orthogonal frequency-division multiplexing (MB-OFDM) ultra-wideband (UWB) technology offers large throughput, low latency and has been adopted in wireless audio\\/video (AV) network products. The complexity and power consumption, however, are still major hurdles for the technology to be widely adopted. In this paper, we propose a unified synchronizer design targeted for MB-OFDM transceiver that achieves high performance with low implementation

Zhenzhen Ye; Chunjie Duan; Philip V. Orlik; Jinyun Zhang; Alhussein A. Abouzeid

2010-01-01

221

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

222

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

PubMed

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

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

2014-07-01

223

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

224

Obstacle avoidance and concealed target detection using the Army Research Lab ultra-wideband synchronous impulse reconstruction (UWB SIRE) forward imaging radar  

NASA Astrophysics Data System (ADS)

The U.S. Army Research Laboratory (ARL), as part of a mission and customer funded exploratory program, has developed a new low-frequency, ultra-wideband (UWB) synthetic aperture radar (SAR) for forward imaging to support the Army's vision of an autonomous navigation system for robotic ground vehicles. These unmanned vehicles, equipped with an array of imaging sensors, will be tasked to help detect man-made obstacles such as concealed targets, enemy minefields, and booby traps, as well as other natural obstacles such as ditches, and bodies of water. The ability of UWB radar technology to help detect concealed objects has been documented in the past and could provide an important obstacle avoidance capability for autonomous navigation systems, which would improve the speed and maneuverability of these vehicles and consequently increase the survivability of the U. S. forces on the battlefield. One of the primary features of the radar is the ability to collect and process data at combat pace in an affordable, compact, and lightweight package. To achieve this, the radar is based on the synchronous impulse reconstruction (SIRE) technique where several relatively slow and inexpensive analog-to-digital (A/D) converters are used to sample the wide bandwidth of the radar signals. We conducted an experiment this winter at Aberdeen Proving Ground (APG) to support the phenomenological studies of the backscatter from positive and negative obstacles for autonomous robotic vehicle navigation, as well as the detection of concealed targets of interest to the Army. In this paper, we briefly describe the UWB SIRE radar and the test setup in the experiment. We will also describe the signal processing and the forward imaging techniques used in the experiment. Finally, we will present imagery of man-made obstacles such as barriers, concertina wires, and mines.

Nguyen, Lam; Wong, David; Ressler, Marc; Koenig, Francois; Stanton, Brian; Smith, Gregory; Sichina, Jeffrey; Kappra, Karl

2007-04-01

225

0.7-GHz-Bandwidth DS-UWB-IR System for Low-Power Wireless Communications  

NASA Astrophysics Data System (ADS)

A direct-sequence ultra-wideband impulse radio (DSUWB-IR) system is developed for low-power wireless applications such as wireless sensor networks. This system adopts impulse radio characterized by a low duty cycle, and a direct-sequence 0.7-GHz bandwidth, which enables low-power operation and extremely precise positioning. Simulation results reveal that the system achieves a 250-kbps data rate for 30-mdistance wireless communications using realistic specifications. We also conduct an experiment that confirms the feasibility of our system.

Fujiwara, Ryosuke; Maeki, Akira; Mizugaki, Kenichi; Ono, Goichi; Nakagawa, Tatsuo; Norimatsu, Takayasu; Kokubo, Masaru; Miyazaki, Masayuki; Okuma, Yasuyuki; Hayakawa, Miki; Kobayashi, Shinsuke; Koshizuka, Noboru; Sakamura, Ken

226

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

227

An Efficient Supply Modulator for Linear Wideband RF Power Amplifiers  

E-print Network

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

Turkson, Richard

2011-10-21

228

IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 49, NO. 5, MAY 2014 1223 Nanostructured CMOS Wireless Ultra-Wideband  

E-print Network

8.6 pA to 350 nA. The on-chip programmable waveform generator provides a wide range of user fabricated in a 0.13 µm standard CMOS technology has been validated in prostate cancer synthetic DNA of sugars and phos- phate groups joined by ester bonds. Each nucleotide consists of three units: a phosphate

Genov, Roman

229

Channel models for wireless body area networks.  

PubMed

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

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

2008-01-01

230

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

PubMed

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

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

2014-09-01

231

Wireless, Ultra-Low-Power Implantable Sensor for Chronic Bladder Pressure Monitoring  

Microsoft Academic Search

The wireless implantable\\/intracavity micromanometer (WIMM) system was designed to fulfill the unmet need for a chronic bladder pressure sensing device in urological fields such as urodynamics for diagnosis and neuromodulation for bladder control. Neuromodulation in particular would benefit from a wireless bladder pressure sensor which could provide real-time pressure feedback to an implanted stimulator, resulting in greater bladder capacity while

Steve J. A. Majerus; Steven L. Garverick; Michael A. Suster; Paul C. Fletter; Margot S. Damaser

2012-01-01

232

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

233

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.

234

PicoRadio Supports Ad Hoc Ultra-Low Power Wireless Networking  

Microsoft Academic Search

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

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

2000-01-01

235

An Ultra-low-supply Dual-band VCO for Wireless Sensor Networks  

Microsoft Academic Search

Aggressive scaling down reduces the supply voltage of digital integrated circuits continuously. In order to realize systems-on-a-chip (SOC), analog and RF circuits should also work under the reduced voltage. For wireless sensor networks (WSN), low supply is important for communication nodes as the supply voltage must be low enough under a single solar cell as power source. Besides, the future

Bo Zhao; Yongpan Liu; Pengpeng Chen; Tao Chen; Huazhong Yang; Hui Wang

2009-01-01

236

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

E-print Network

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

Tu, Wen-Hua

2009-05-15

237

Asymmetrically-loaded interdigital coupled line for wideband microstrip bandpass filters  

E-print Network

at least twice. Very recently, this three coupled-line structure in the format of an interdigital capacitor has been employed to constitute an ultra-wideband (UWB) bandpass filter [5]. Moreover, by extending

Leung, Ka-Cheong

238

Effects of Quantization in Systolic 2D IIR Beam Filters on UWB Wireless Communications  

Microsoft Academic Search

Ultra-wideband (UWB) wireless beamforming systems may potentially be implemented digitally at multi-gigahertz clock frequencies\\u000a using low-precision systolic array realizations of two-dimensional (2D) infinite impulse response (IIR) beam plane-wave filters.\\u000a The finite precision performance of such filters is analyzed in terms of quantization noise. Extensive Monte Carlo simulations\\u000a are performed using test vectors that are derived from 2D finite-difference time-domain (FDTD)

Sean Victor Hum; Leonard T. Bruton

239

One-Way Ranging Method Using Reference-Based Broadcasting Messages for Wireless Sensor Networks  

NASA Astrophysics Data System (ADS)

This paper proposes a one-way ranging method using reference-based broadcasting messages. The method is based on impulse radio UWB (Ultra-wideband) for wireless sensor networks. The proposed method reduces traffic overheads and increases the ranging accuracy using frequency offsets and counter information based on virtually synchronized counters between RNs (Reference Nodes) and MNs (Mobile Nodes). Simulation results show that the proposed method can alleviate the ranging errors comparing to SDS-TWR (Symmetric Double-Sided Two-Way Ranging) method in terms of the frequency offset.

Lee, Cheolhyo; Nam, Yoon-Seok; Kim, Jae-Young; Cho, You-Ze

240

A Wideband MIMO Channel Simulator using the Kronecker Model  

Microsoft Academic Search

Here we are presenting a simulator for a wireless wideband multiple-input multiple-output (MIMO) channel by considering the prolate spheroidal wave functions (PSWF) set as a universal basis for the temporal correlation properties of the separable MIMO channel using the Kronecker method

Alberto Alcocer-Ochoa; Valeri Ya. Kontorovitch; R. Parra-Michel

2006-01-01

241

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

242

Wideband microwave\\/millimeter-wave solid-state amplifiers  

Microsoft Academic Search

Rapid strides have been made in recent years in the design and development of ultra-wideband solid-state amplifiers. A variety of design approaches based on GaAs FET and silicon bipolar technologies have been proposed. These include, among others, balanced amplifiers with couplers, reactive and resistive gain compensated circuits, feedback amplifiers, and traveling wave or distributed amplifiers . . . Panelists will

R. Pucel

1983-01-01

243

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

Microsoft Academic Search

The performance of future wireless communication systems can be highly increased by utilizing multiple antennas at both sides of a wireless communication link. A concept for MIMO double directional wide-band channel measurements is presented and high-resolution channel parameter estimation is applied. Furthermore, a procedure, where MIMO capacities are obtained by one single SISO channel transfer function, is discussed. Finally, a

Thomas Fiigen; Gerd Sommerkorn; Jürgen Maurer; Dirk Hampicke; Werner Wiesbeck; Reiner Thomä

2002-01-01

244

Photonic generation and wireless transmission of different pulse modulation formats for high-speed impulse radio ultrawideband over fiber systems  

NASA Astrophysics Data System (ADS)

Novel methods on photonic generation of different pulse modulation formats for impulse radio ultra-wideband (IR-UWB) over fiber application is overviewed. A flexible, high-speed and power-efficient photonic on-off keying and binary phase shift keying modulated IR-UWB over fiber communication system is proposed and demonstrated. IR-UWB transmission over 20km fiber and 0.25m wireless link without any compensation is presented. The transmission performance for both modulation formats is evaluated and compared by measuring eye diagrams and the electrical spectra.

Xie, Shizhong; Chen, Hongwei; Chen, Minghua; Yang, Sigang; Li, Pengxiao

2011-12-01

245

Wideband active antenna cancellation  

E-print Network

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

Adaniya, Hana L

2008-01-01

246

Radio frequency identification enabled wireless sensing for intelligent food logistics.  

PubMed

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

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

2014-06-13

247

710 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 56, NO. 3, MARCH 2008 Dispersion Limitations of Ultra-Wideband Wireless  

E-print Network

of interest. While virtually nondispersive antennas do exist, such as the planar bowtie [5] or the ridged horn Archimedean spiral antennas) with variable-bandwidth excitation waveforms, we first demonstrate the nonuniform phase response of the spiral antennas utilized in the link. Such waveforms remove the dispersion

Purdue University

248

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

E-print Network

. In general, sensor medium access control (MAC) protocols reduce duty cycle to achieve longer life time cycle of wireless nodes is a key factor that determines the life time of wireless sensor networks of low to extremely low duty cycle. It reduces the energy consumption in communications by minimizing

Bahk, Saewoong

249

ULTRA WIDEBAND ROSE LEAF MICROSTRIP PATCH ANTENNA  

Microsoft Academic Search

In this paper a novel rose leaf shape microstrip antenna with capacitively coupled rectangular fed is presented.Various shapes of capacitive coupled fed are compared and optimized by successive iterations of a computer-aided analysis.The Ansoft HFSS is employed for analysis at the frequency band of 4.3 GHz-8.3 GHz. The antenna is fabricated and measurement results show a very good agreement with

Abbas Ali Lotfi Neyestanak; Shahre Rey Branch

2008-01-01

250

Ultra-Wideband Digital Receiver LNA Design  

E-print Network

output SNR, which is defined as the matched filter bound. ­ Applies equally to broadband and narrowband power dissipation. #12;Existing Work · Narrowband matching. ­ Single-tone assumption. · NF = (output on signal and noise spectrum. · SNR defined as the matched filter bound. ­ Whitened matched filter for one

Southern California, University of

251

Ultra-wideband tomography of land cover  

NASA Astrophysics Data System (ADS)

This paper describes a comprehensive approach which combines the application of OKO-2 ground penetrating radar, conventional method of cross sectioning accepted in edaphology, soil-testing parameters, mobile and laboratory research of dielectric permittivity for stratified soil cover research. Dielectric characteristics measurements of selected contact samples by the waveguide-coaxial technique showed a correlation between electrophysic characteristics of soil with soil moisture and density. Location of deep aquifers was detected and the real local topography was restored. Research was performed within the Timiryazevskoye forest district near Tomsk. Comparing the results of radar non-destructive sounding and contact measurements demonstrated high correlation of detected structural soil features. The suggested approach provides a solid basis for verifying the non-contact radiophysical methods of research in the interests of rational nature management and land utilization.

Kochetkova, Tatiana D.; Zapasnoy, Andrey S.; Klokov, Andrey V.; Shipilov, Sergey E.; Yakubov, Vladimir P.; Yurchenko, Alexey V.

2014-11-01

252

Step-by-Step Modification of Printed Wideband Balun for GPR Antennas  

Microsoft Academic Search

Several designs of ultra-wideband (UWB) micro-strip to slotline transitions for tapered-slot antennas (TSA) have been considered. A fourth-order Marchand microstrip-slotline balun and two transitions using wideband slot stubs and micro-strip stubs have been simulated using CST Microwave Studio. TSA employing these baluns had been designed, fabricated and tested. The results of simulations and experimental data are presented.

Ye. Maksimovitch; V. Mikhnev; P. Vainikainen

2007-01-01

253

The analysis of wideband conformal microstrip array antenna with cosecant-squared beam shaping  

Microsoft Academic Search

The characteristics of new ultra wideband (UWB) like fractal microstrip patch antenna element and 24×10 elements wideband conformal microstrip array antenna using non-uniform photonic bandgap (PBG) substrate structure whose gap positions enhance some modes and weaken others have been analyzed using a full 3D electromagnetic field inside a structure based on the finite element method (FEM). The cosec2 elevation beam

Yasser M. Madany

2006-01-01

254

Modeling of Localization Error in Wireless Sensor Network  

NASA Astrophysics Data System (ADS)

This letter presents the variation of localization error to network parameters, the number of range estimation results from anchor nodes (ANs) and average distance between ANs in centralized Wireless Sensor Network (WSN). In sensor network, ANs estimate the relative range to Target Node (TN) using Time-Of-Arrival (TOA) information of Ultra WideBand (UWB) radio and a fusion center determines the final localization of TN based on estimation results reported. From simulation results, the variation of localization error, which is defined as the difference between localization result of TN and its actual location, is represented as the function of number of estimation results to average distance between ANs. The distribution of localization error is matched to the Rician distribution whose K-factor value is given by the proposed formula as well. Finally, the normalized error function for the efficient localization network design is characterized.

Choi, Jinwon; Kang, Jun-Sung; Kim, Yong-Hwa; Kim, Seong-Cheol

255

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

PubMed

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

Keong, Ho Chee; Yuce, Mehmet R

2009-01-01

256

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

PubMed

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

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

2014-01-01

257

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

258

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

E-print Network

Centralized route recovery based on multi-hop wakeup time estimation for wireless sensor networks packet flooding for route recovery and solves the high energy consumption problem caused by each node sensor networks (WSNs) are currently used in various fields and play an important role for creating smart

Bahk, Saewoong

259

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

E-print Network

tags that can be integrated with batteries and sensors for wireless sensing, tracking and monitoring sealing. Both approaches have been successfully demonstrated for printing conductors on paper substrates sensors and batteries to be mounted or embedded. A fast ink jet printing process can be used efficiently

Tentzeris, Manos

260

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

Microsoft Academic Search

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

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

2011-01-01

261

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

262

Ultra-short pulse generator  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1993-01-01

263

Wideband radar (advantages and problems)  

Microsoft Academic Search

Review of advantages and problems of wideband radar is given. Some criteria of wideband (UWB) radar are discussed to avoid misunderstanding when only the relative signal bandwidth is used as a criterion. Brief historical outline of the first and follow up experiments by different authors is presented. Advantages and disadvantages of bandwidth widening can be compared using the computer simulation

Y. D. Shirman; S. P. Leshchenko; V. M. Orlenko

2004-01-01

264

A novel compression ratio allocation method for collaborative wideband spectrum sensing  

Microsoft Academic Search

Spectrum sensing, as a key technology of cognitive radio (CR), needs to reliably and efficiently detect spectrum holes in wireless environments, which challenges the traditional spectral estimation methods typically operating at or above Nyquist rates. This paper develops a novel compression ratio allocation (CRA) method for wideband spectrum sensing in CR networks. In our scheme, each CR terminal performs compressed

Di Zhang; Zhiyong Feng; Zaili Wang; Ying Wang; Ping Zhang

2012-01-01

265

Prediction of Fast Fading Mobile Radio Channels in Wideband Communication Systems  

E-print Network

Prediction of Fast Fading Mobile Radio Channels in Wideband Communication Systems Liang Dong on the performance of wireless communication systems, such that the prediction of the changing channel behaviors-frequency prediction scheme has superior performance over conducting the channel predic- tion on a single frequency. I

Dong, Liang

266

Wideband plasmonic focusing metasurfaces  

NASA Astrophysics Data System (ADS)

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

Saeidi, Chiya; Weide, Daniel van der

2014-08-01

267

ULTRA Light Augmented Reality Mobile System  

Microsoft Academic Search

This system paper presents ULTRA, a light and compact system that applies augmented reality techniques to handheld PCs. ULTRA offers a comfortable and unobtrusive solution that integrates augmented reality functionalities with near-the-eye display, wireless connection and remote support over integrated mobile phone. The application areas of the ULTRA system span multiple domains such as the maintenance and support of complex

Alexandra Makri; Jens Weidenhausen; Peter Eschler; Didier Stricker; Oliver Machui; Carlos Fernandes; Sergio Maria; Gerrit Voss; Nikolaos Ioannidis

268

Theory of a wideband distribution gyrotron travelling wave amplifier  

NASA Astrophysics Data System (ADS)

We present the concept of an ultra-wideband distributed gyrotron travelling wave amplifier for millimeter and submillimeter waves. The radius of the waveguide in the interaction region is increased along the axis while the strength of the d.c. magnetic field is decreased in such a way that the wave cutoff frequency is kept nearly equal to the electron cyclotron frequency. The basic principle of operation, peak gain, and saturated efficiency are analyzed. It is shown that instantaneous bandwidth over at least two octaves is theoretically possible. Technological requirements for achieving such an amplifier are assessed, including proposed structures for distributed input wave coupling.

Chu, K. R.; Lau, Y. Y.; Barnett, L. R.; Granatstein, V. L.

1981-06-01

269

Wireless Technologies in Support of ISS Experimentation and Operations  

NASA Technical Reports Server (NTRS)

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

Wagner, Raymond; Fink, Patrick

2012-01-01

270

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

E-print Network

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

Dai, Huaiyu

271

Wide-band CEBG-based Directive Antenna Halim Boutayeb*1, Tayeb A. Denidni1, Peter Perodeau2, and  

E-print Network

Wide-band CEBG-based Directive Antenna Halim Boutayeb*1, Tayeb A. Denidni1, Peter Perodeau2, and Alexandre Marsolais2 1 INRS-EMT, University of Quebec, Montreal, Canada. boutayeb@emt.inrs.ca 2 Ultra-Electronics- tennas or new beam switching antennas [1-3]. These structures are radially and circularly periodic

Boyer, Edmond

272

Modeling of wideband HF channels  

NASA Astrophysics Data System (ADS)

Laboratory simulation of wideband high frequency (HF) system performance is currently not possible because such simulators do not exist. Moreover, there are no validated HF channel models for bandwidths of the order of one megahertz, on which to base the simulator design. Additive distortions, namely noise and interference, in the HF band are briefly reviewed. An introduction and an appraisal of past narrowband HF models are presented: their background, validation tests, and the NTIA/ITS development of the Watterson's simulator. That laboratory tool, judged best by many, works in real time and offers accurate representations of HF channel bandwidth up to 10 or 12 kHz. In the present study an extension to wideband models is attempted. Unfortunately, it suffers from an apparently serious shortage of measured data for the time-varying channel transfer function. A possible wideband model is hypothesized, conjectures are made, many questions are raised, but hardly any are answered. One is left faced with a requirement for an experimental program that is to ascertain the wideband characteristics of multipath fading for digital radio transmission in the HF band and over propagation paths of interest.

Nesenbergs, Martin

1988-03-01

273

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

274

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

SciTech Connect

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

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

2014-05-15

275

A low-power distributed wide-band LNA in 0.18µm CMOS  

Microsoft Academic Search

The implementation of low noise amplifier (LNA) front-ends is one of the challenging aspects in emerging ultra wide-band (UWB) radio frequency (RF) systems. In this paper, we propose a figure of merit (FOM) that captures the tradeoffs among linearity, noise figure (NF), power dissipation and utilization of raw technology speed. Different distributed amplifier (DA) architectures with a 10 dB pass

Srikanth Arekapudi; Echere Iroaga; Boris Murmann

2005-01-01

276

On the use of multipath geometry for wideband cooperative localization  

E-print Network

The combination of wideband transmission and cooperative techniques enables high-precision location-awareness. Wideband transmission provides fine delay resolution and multipath resolvability, while cooperation among nodes ...

Win, Moe Z.

277

2494 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 48, NO. 10, OCTOBER 2013 64-Channel UWB Wireless Neural Vector  

E-print Network

Velazquez, and Roman Genov, Senior Member, IEEE Abstract--An ultra wideband (UWB) 64-channel responsive with tunable switched-capacitor (SC) bandpass filters, 64 multiplying 8-bit SAR ADCs, 64 pro- grammable 16-tap

Genov, Roman

278

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

E-print Network

, ultra-wideband (UWB) circuit design, and organic electronic harvesting techniques will enable ranges. Moreover, solar energy harvesting based on organic semiconductors allows having flexible solarChallenge: Ultra-Low-Power Energy-Harvesting Active Networked Tags (EnHANTs) Maria Gorlatova, Peter

Zussman, Gil

279

Wideband Millimeter Wave Amplification on a Coupled-Cavity Traveling-Wave-Tube Driven by an Impulse Signal  

NASA Astrophysics Data System (ADS)

We present simulation results on wideband millimeter wave amplification on a coupled-cavity traveling-wave-tube driven by an ultra short impulse signal. The impulse signal of pulse width of 1 nsec modulated with a carrier frequency of 29.1 GHz is injected into the amplifier. The resulting output spectra were found to be wideband with a 2.4% fractional bandwidth at a center frequency of 29.1 GHz, where peak output power of 658 W remained same as that obtained at CW operation with a single drive frequency of 29.1 GHz.

Choi, Jin Joo; Kim, Hyoung Jong

2011-01-01

280

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

281

Leakage-Aware Energy Synchronization for Wireless Sensor Networks  

E-print Network

for wireless sensor de- vices. The starting point of this work is TwinStar, which uses ultra-capacitor, Experimentation Keywords Energy, Ultra-capacitor, Leakage, Wireless Sensor Networks 1. INTRODUCTION beneficial, because energy storage units (e.g., batteries or capacitors) are limited in capacity and leakage

Zhang, Zhi-Li

282

Evaluation of an ultra-wide-band 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 measurements into wavefronts impinging on the receiving array is presented. Based on a modification of the CLEAN algorithm, this approach provides

R. Jean-Marc Cramer; Robert A. Scholtz; Moe Z. Win

2002-01-01

283

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

NASA Astrophysics Data System (ADS)

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

Issa Ahmed, Rudhwan

284

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

PubMed

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

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

2014-01-01

285

Constrained State Estimation for Individual Localization in Wireless Body Sensor Networks  

PubMed Central

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

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

2014-01-01

286

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

PubMed Central

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

Chóliz, Juan; Hernández, Ángela; Valdovinos, Antonio

2011-01-01

287

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

288

MISO CDMA transmission with simplified receiver for wireless communication handsets  

Microsoft Academic Search

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

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

2001-01-01

289

Fundamental limits of wideband localization  

E-print Network

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

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

2008-01-01

290

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

291

Ultra wideband horn antenna for microwave imaging application  

Microsoft Academic Search

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

Hana Amjadi; Farzad Tavakkol Hamedani

2011-01-01

292

Printed-Circuit Antennas for Ultra-Wideband Monitoring Applications  

E-print Network

a time-domain technique (CST Microwave Studio) and feeding an UWB pulse to the input of the microstrip-spread and addresses issues such as EIRP compliance [2], immunity tests [3], interference [4], high-power microwave

Bornemann, Jens

293

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

294

OPTIMIZED ULTRA-WIDEBAND RADIATION OF DIPOLE ANTENNAS WITH TRIANGLE  

E-print Network

, including pulsed antennas. These generic problems have been widely explored through full-wave numerical electromagnetic solvers, the E- and K-pulse signal processing techniques, and other fashions. Previous work often mainly on signal processing like E- and K-pulse techniques are not well suited for direct implementation

Southern California, University of

295

Ultra-wideband printed circular monopole antenna array  

Microsoft Academic Search

In this paper, a printed monopole circular antenna array concept for use in the frequency 3.1 GHz - 10.6 GHz is presented. The design uses the printed monopole disc antenna in a four-element array to produce high gain and to shape the radiation pattern while maintaining good match of the frequency range of interest. The four printed disc monopole antennas

Zainul Ihsan; Klaus Solbach

2009-01-01

296

75 FR 62476 - Ultra-Wideband Transmission Systems  

Federal Register 2010, 2011, 2012, 2013, 2014

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

2010-10-12

297

Recent Progress in Ultra-Wideband Microwave Breast Cancer Detection  

E-print Network

to find new methods for the early detection of breast cancer in order to provide treatment to patients screening methods include mammography, ultrasound techniques, and magnetic resonance imaging (MRI). Mammography is the most common method currently being clinically employed and promoted as a regular screening

Coates, Mark

298

Ultra-wideband source using gallium arsenide photoconductive semiconductor switches  

Microsoft Academic Search

An ultrawide-band (UWB) pulse generator based on high-gain (lock-on mode) gallium arsenide (GaAs) photoconductive semiconductor switches (PCSS's) is presented. Revised PCSS contact design shows improved performance in hold-off field, on-state switch potential, and switching jitter, while reducing the switch volume by 75% compared to previous designs. A compact laser diode module operates at 904 nm and triggers the PCSS at

Jon S. H. Schoenberg; Jeffrey W. Burger; J. Scott Tyo; Michael D. Abdalla; Michael C. Skipper; Walter R. Buchwald

1997-01-01

299

Wideband Piezomagnetoelastic Vibration Energy Harvesting  

NASA Astrophysics Data System (ADS)

This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation is achieved by placing the cantilever in a magnetic field induced by either one or two magnets located oppositely of the cantilever. The attraction force created by the magnetic field and iron foils introduces a mechanical force in opposite direction of the cantilevers restoring force causing a spring softening effect. In linear operation (without magnets) the harvester generates a RMS power of 141 ?W/g2 at 588 Hz with a relative bandwidth of 3.8% over a 100 k? load resistor. When operated with one magnet ideally positioned opposite the cantilever, a RMS power of 265 ?W/g2 is generated at 270 Hz with a relative bandwidth of 25%.

Lei, Anders; Thomsen, Erik V.

2014-11-01

300

Inkjet-Printed Planar Antenna for a Wireless Sensor on Paper Operating at Wi-Fi Frequency  

E-print Network

is one of the leading solutions to realize ultra-low-cost and "green" wireless sensor applications substrates applied to wireless sensors networks (WSNs) [1][2], Ultra Wide Band (UWB) modules [3], wireless network described in [8] consisting of three inductors and one capacitor was used to match

Tentzeris, Manos

301

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

E-print Network

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

Mercier, Patrick P.

302

Information Raining for Mobile Hotspots in 4G Wireless Networks  

E-print Network

Cellular Optical WLAN Fast Ethernet 100 Information Raining Fig. 1. Mobility versus bandwidth plot cellular systems have not been designed to support the speeds beyond 250 km/h. The second challenge arises), ultra wideband (UWB), etc, it is possible to achieve bit rates in the order of 100 Mbit/s for fast

Valaee, Shahrokh

303

A novel wideband gyrotron travelling wave amplifier  

E-print Network

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

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

2003-01-01

304

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

PubMed

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

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

2009-08-01

305

Wideband embedded/conformal antenna subsystem concept  

NASA Astrophysics Data System (ADS)

The concept for a wideband, embedded/conformal antenna subsystem is presented. A multilayer radome not only protects the antenna from hostile environments, but also is designed to sustain aircraft dynamic loading. The radiating element consists of a planar, dual- flared slot capable of high-performance, multioctave operation. Advanced materials are currently being developed to enhance the low profile and efficient, wideband performance of the radiating element.

Smalanskas, Joseph P.; Valentine, Gary W.; Wolfson, Ronald I.

1991-10-01

306

Wideband Timing of Millisecond Pulsars  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

307

Fiber wireless networks  

NASA Astrophysics Data System (ADS)

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

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

2005-11-01

308

Quasi-orthogonal wideband radar waveforms based on chaotic systems  

E-print Network

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

Willsey, Matt (Matt S.)

2007-01-01

309

WIDEBAND SLOT AND PRINTED ANTENNAS ATEF Z. ELSHERBENI  

E-print Network

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

Elsherbeni, Atef Z.

310

Design of a miniature wideband radar experimental system  

Microsoft Academic Search

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

Zhang Xiao-wei; Li Ming; Zuo Lei

2011-01-01

311

Wideband Agile Digital Microwave Radiometer  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

312

SPS Wideband Transverse Feedback Kicker: Design Report  

E-print Network

The SPS wideband transverse feedback system is being developed to control vertical beam instabilities arising from intensity dependent effects like electron cloud instability (ECI) and the transverse mode coupling instability (TMCI). As part of the LHC Injector Upgrade (LIU) project, a wideband kicker is necessary as a damper to control unstable modes within a bunch. Several types of kicker structures, including cavities, striplines, and slotted structures have been studied to evaluate the operating bandwidth, transverse shunt impedance, and beam coupling impedance. Studies and results from all structures are described below, including three potential paths to implement these structures as a wideband kicker system. A single, slotted-coaxial kicker of 1 m length provides substantial kick strength (integrated transverse voltage) over a bandwidth ranging from nearly DC to 1 GHz. An array of four 10 cm long striplines provides substantial kick strength from DC to 750 MHz. For a given amplifier power of 500 W, th...

Cesaratto, J M; Rivetta, C H; Alesini, D; Drago, A; Gallo, A; Marcellini, F; Zobov, M; De Santis, S; Paret, Z; Ratti, A; Qian, H; Bartosik, H; Hofle, W; Zannini, C

2013-01-01

313

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

PubMed

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

Ebrazeh, Ali; Mohseni, Pedram

2014-08-12

314

Ultra wide band signal design by angular and radial prolate spheroidal wave functions (PSWF)  

Microsoft Academic Search

Prolate spheroidal wave functions (PSWF) provide significant advantage in ultra wideband (UWB) pulse-shapes design because of the time limited nature and wide bandwidth of such orthogonal signal waveforms. In this paper, we show the design procedure for UWB pulses utilizing the joining properties of radial and angular PSWF. Results in the paper demonstrate utility of eigenvalues and power spectral properties

D. Adhikari; C. Bhattacharya

2011-01-01

315

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

PubMed Central

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

Jow, Uei-Ming; Ghovanloo, Maysam

2011-01-01

316

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

PubMed

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

Pan, Shilong; Yao, Jianping

2011-12-12

317

Medium access control and network layer design for 60 GHz wireless personal area networks  

Microsoft Academic Search

The unlicensed frequency band around 60 GHz is a very promising spectrum due to its potential to provide multiple gigabits per second based data rates for short range wireless communication. Hence, 60 GHz radio is an attractive candidate to enable ultra high rate Wireless Personal Area Networks (WPANs), which are expected to support wireless multimedia applications like high-definition video streaming,

X. An

2010-01-01

318

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

E-print Network

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

Sarabandi, Kamal

319

A novel wideband 140 GHz gyrotron amplifier  

E-print Network

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

Joye, Colin D., 1980-

2008-01-01

320

Wideband radar micro-doppler applications  

NASA Astrophysics Data System (ADS)

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

Tahmoush, Dave

2013-05-01

321

Efficient and wideband horn nanoantenna.  

PubMed

In this Letter, we present the design of a horn nanoantenna working at near-IR frequencies. The proposed layout consists of an Ag-air-Ag nanotransmission line terminated in a tapered horn. The antenna design is validated through proper full-wave numerical simulations, taking into account actual dispersion and losses of the involved materials. The numerical results show that the designed nanohorn is matched over a broad range of frequencies (more than 50% of fractional bandwidth) and radiates efficiently in the same frequency band (the realized gain is greater than 10 ?dBi). Such promising results may find application in different technical and scientific fields, ranging from smart lighting to optical wireless communications. PMID:21593876

Ramaccia, D; Bilotti, F; Toscano, A; Massaro, A

2011-05-15

322

Globally optimal transmitter placement for indoor wireless communication systems  

Microsoft Academic Search

A global optimization technique is applied to solve the optimal transmitter placement problem for indoor wireless systems. An efficient pattern search algorithm— DIviding RECT- angles (DIRECT) of Jones et al.—has been connected to a parallel three-dimensional radio propagation ray tracing modeler running on a 200-node Beowulf cluster of Linux workstations. Surrogate functions for a parallel wideband code-division multiple-access (WCDMA) simulator

Jian He; Alex A. Verstak; Layne T. Watson; Cheryl A. Stinson; Naren Ramakrishnan; Clifford A. Shaffer; Theodore S. Rappaport; Christopher R. Anderson; Kyung Kyoon Bae; Jing Jiang; William H. Tranter

2004-01-01

323

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

324

Wideband Circularly-Polarized Patch Antenna  

Microsoft Academic Search

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

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

2006-01-01

325

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

326

Distributed Compressive Wide-Band Spectrum Sensing  

Microsoft Academic Search

óWe consider a compressive wide-band spectrum sensing scheme for cognitive radio networks. Each cognitive radio (CR) sensing receiver transforms the received analog signal from the licensed system in to a digital signal using an analog-to- information converter. The autocorrelation of the compressed signal is then collected from each CR at a fusion center. A compressive sampling recovery algorithm that exploits

Ying Wang; Ashish Pandharipande; Yvan Lamelas Poloy; Geert Leusy

327

Distributed compressive wide-band spectrum sensing  

Microsoft Academic Search

We consider a compressive wide-band spectrum sensing scheme for cognitive radio networks. Each cognitive radio (CR) sensing receiver transforms the received analog signal from the licensed system in to a digital signal using an analog-to-information converter. The autocorrelation of the compressed signal is then collected from each CR at a fusion center. A compressive sampling recovery algorithm that exploits joint

Ying Wang; Ashish Pandharipande; Yvan Lamelas Polo; Geert Leus

2009-01-01

328

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

329

A wideband coplanar stripline to microstrip transition  

Microsoft Academic Search

A wideband coplanar stripline (CPS)-to-microstrip line was developed. The transition has a simple structure for the ease of fabrication with low cost. The measured performance of two back-to-back transitions exhibits an insertion loss of less than 3 dB and a return loss of better than 10 dB over a bandwidth from 1.3 GHz to 13.3 GHz (1:10.2). For narrower bandwidth,

Young-Ho Suh; Kai Chang

2001-01-01

330

Holographic processing of wideband antenna data  

Microsoft Academic Search

To utilize the real-time two-dimensional coherent imaging devices for antenna data processing, the properties of a raster-scanned wideband signal are studied. To extend the processed bandwidth-duration product widely over the recording capability of a single line on the imaging device, the time signal is displayed on several lines of the raster. The time-Doppler ambiguity function of the resulting 2-D signal

G. Lebreton; E. de Bazelaire

1980-01-01

331

Design of a Wideband Radio Telescope  

Microsoft Academic Search

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

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

2007-01-01

332

Non-line-of-sight Node Localization based on Semi-Definite Programming in Wireless Sensor Networks  

E-print Network

An unknown-position sensor can be localized if there are three or more anchors making time-of-arrival (TOA) measurements of a signal from it. However, the location errors can be very large due to the fact that some of the measurements are from non-line-of-sight (NLOS) paths. In this paper, we propose a semi-definite programming (SDP) based node localization algorithm in NLOS environment for ultra-wideband (UWB) wireless sensor networks. The positions of sensors can be estimated using the distance estimates from location-aware anchors as well as other sensors. However, in the absence of LOS paths, e.g., in indoor networks, the NLOS range estimates can be significantly biased. As a result, the NLOS error can remarkably decrease the location accuracy. And it is not easy to efficiently distinguish LOS from NLOS measurements. In this paper, an algorithm is proposed that achieves high location accuracy without the need of identifying NLOS and LOS measurement.

Chen, Hongyang; Wang, Zizhuo; So, H C; Poor, H Vincent

2010-01-01

333

Wideband propagation measurements onboard HMS Bristol  

Microsoft Academic Search

A modern warship has many complex systems for onboard communications, command and control. At present, all of these systems are hard-wired and are expensive to modify or replace for the many upgrades that occur during the lifetime of the ship. It would be advantageous to replace much of this cabling with wireless links and to use COTS wireless local area

Philip Nobles; Lt Richard Scott

2003-01-01

334

An ultra-compact and efficient Li-ion battery charger circuit for biomedical applications  

E-print Network

This paper describes an ultra-compact analog lithium-ion (Li-ion) battery charger for wirelessly powered implantable medical devices. The charger presented here takes advantage of the tanh output current profile of an ...

Do Valle, Bruno Guimaraes

335

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

PubMed

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

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

2011-06-01

336

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 6, 2007 515 A Tunable Antenna for DVB-H Applications  

E-print Network

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 6, 2007 515 A Tunable Antenna for DVB wideband built-in antenna with resonance frequency variability for digital video broadcasting-handheld (DVB-H) is proposed. The tunable antenna consists of two channel matching networks and a spiral-shaped monopole type

Park, Seong-Ook

337

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

E-print Network

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

Tentzeris, Manos

338

Chalipa, a novel wideband circularly polarized microstrip fractal antenna  

Microsoft Academic Search

An improved wideband circularly polarized microstrip antenna is here proposed and analyzed. The radiating structure consists of a simple patch with a basic shape ldquoChalipardquo, two rotated broken and crossed ldquoSrdquo, which has been iterated by a fractal pattern achieving a multiband or even wideband, structure. The basic shape represents a clockwise rotation that results in the same rotation of

Maryam Rahmani; A. Tavakoli; H. R. Amindavar; A. M. Reza; P. Dehkhoda

2009-01-01

339

Survey of worldwide high-power wideband capabilities  

Microsoft Academic Search

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

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

2004-01-01

340

NONLINEARITY CORRECTION ALGORITHM FOR WIDEBAND FMCW RADARS Andrei Anghel  

E-print Network

NONLINEARITY CORRECTION ALGORITHM FOR WIDEBAND FMCW RADARS Andrei Anghel Gabriel Vasile Remus- rithm for wideband frequency modulated continuous wave (FMCW) radars based on high-order ambiguity functions (HAF) and time resampling. By emphasizing the polynomial- phase nature of the FMCW signal

Paris-Sud XI, Université de

341

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

NASA Astrophysics Data System (ADS)

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

Weintroub, Jonathan

2014-06-01

342

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

343

Dual-Vivaldi wideband nanoantenna with high radiation efficiency over the infrared frequency band.  

PubMed

A dual-Vivaldi nanoantenna is proposed to demonstrate the possibility of wideband operation at IR frequencies. The antenna geometry design is guided by the material properties of metals at IR frequencies. According to our numerical results, this nanoantenna has both high radiation efficiency and good impedance-matching properties over a wide frequency band (more than 122%) in the IR frequency band. The design is based on the well-known Vivaldi antenna placed on quartz substrate but operating as a pair instead of a single element. Such a pair of Vivaldi antennas oriented in opposite directions produces the main lobe in the broadside direction (normal to the axes of the antennas) rather than the usual peak gain along the axis (end fire) of a single Vivaldi antenna. The dual-Vivaldi nanoantenna is easy to fabricate in a conventional electron-beam lithography process, and it provides a large number of degrees of freedom, facilitating design for ultra-wideband operation. PMID:21808308

Iluz, Zeev; Boag, Amir

2011-08-01

344

Miniature biotelemeter gives multichannel wideband biomedical data  

NASA Technical Reports Server (NTRS)

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

Carraway, J. B.

1972-01-01

345

Real-time wideband holographic surveillance system  

DOEpatents

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

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

1996-01-01

346

Wideband low loss double mode SAW filters  

Microsoft Academic Search

A method is discussed for achieving a wideband low-loss longitudinally coupled double mode surface acoustic wave (SAW) (DMS) filter using a leaky SAW on a 36° Y-X LiTaO3 and 64° Y-X LiNbO3 substrate with a high electromechanical coupling factor. Its characteristics are analyzed by computer simulation. With the use of the first-mode and third-mode resonance on a 64° Y-X LiNbO3

Takao Morita; Y. Watanabe; M. Tanaka; Y. Nakazawa

1992-01-01

347

1818 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 4, NO. 4, JULY 2005 A General Model and SINR Analysis of Low  

E-print Network

in the presence of narrowband interference, multipath and additive white Gaussian noise, for both matched- filter and SINR Analysis of Low Duty-Cycle UWB Access Through Multipath With Narrowband Interference and Rake coexisting narrowband services is a critical factor affecting performance of ultra-wideband (UWB) radio

Yang, Liuqing

348

1930 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 5, NO. 7, JULY 2006 Low-Complexity Blind Synchronization and  

E-print Network

communication systems: from classical narrowband and emerging (ultra) wideband (UWB) point-to-point links- nications. In narrowband (NB) transmissions over additive white Gaussian noise (AWGN) channels, timing acquisition amounts to peak-picking the correlation of the transmit-filter with its template formed

Giannakis, Georgios

349

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.

350

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

351

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

NASA Astrophysics Data System (ADS)

A fully-integrated SiGe wide band amplifier implemented in a standard low cost 0.35 ?m 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 amplifying device in a multisection reactive network so that the overall input reactance is resonated over a wider bandwidth. The second stage is a cascode transistor to obtain a great power gain and a high isolation between input and output ports. In adition, by adjusting the area and the multiplicity of these transistors, we can reduce the noise figure of the circuit. Finally at the output a new technique is used to increase the bandwidth. This technique is based in the replacement of the load resistor by a shunt-peaking resistor composed by an inductor and a resistor. The addition of an inductance gives an output impedance that remains roughly constant over a broader frequency range. Chip dimensions are 0.665 × 0.665 mm2 and power dissipation is 39 mW, drawn from a 3.3V supply. The noise figure ranges from 3.5 to 7.5 in the band between 2 GHz and 8.5 GHz. Finally, the circuit core draws 5.3 mA from a 3.3-V supply. All this results were measured in a probe station.

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

2007-05-01

352

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.

353

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

Code of Federal Regulations, 2010 CFR

...wideband operations in the 700 MHz public safety spectrum. 90.1432 Section 90...COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND...wideband operations in the 700 MHz public safety spectrum. (a) Wideband...

2010-10-01

354

A New Compact Ultra Wide Band (UWB) Planar Antenna using Glass as Substrate  

Microsoft Academic Search

In this paper, we present a new planar waveguide-fed ultra wideband (UWB) antenna. This antenna is designed for 50 ? feed on a loss less glass as a substrate. The impedance bandwidth with VSWR < 2 is from about 4.4 GHz to more than 12 GHz in simulation results but from 3.8 GHz to about 11.5 GHz in measurement. This

S. A. Hosseini; Z. Atlasbaf; K. Forooraghi

2008-01-01

355

Observation of ultra-high-energy cosmic rays with the ANITA balloon-borne radio interferometer  

Microsoft Academic Search

We report the observation of 16 cosmic-ray events of mean energy of 1.5×1019eV, via a process known as geosynchrotron emission where radio pulses originate from the interaction of the cosmic-ray air shower with the Antarctic geomagnetic field. These are the first ultra-wideband, far-field measurements of the radio spectral density of geosynchrotron emission in the range from 300 to 1000MHz. The

A. Romero-Wolf; S. Hoover; J. Nam; P. W. Gorham; E. Grashorn; P. Allison; S. W. Barwick; J. J. Beatty; K. Belov; D. Z. Besson; W. R. Binns; C. Chen; P. Chen; J. M. Clem; A. Connolly; P. F. Dowkontt; M. A. DuVernois; R. C. Field; D. Goldstein; A. G. Vieregg; C. L. Hebert; M. H. Israel; A. Javaid; J. Kowalski; J. G. Learned; K. M. Liewer; J. T. Link; E. Lusczek; S. Matsuno; B. C. Mercurio; C. Miki; P. Mio?inovi?; C. J. Naudet; J. Ng; R. J. Nichol; K. Palladino; K. Reil; M. Rosen; L. Ruckman; D. Saltzberg; D. Seckel; G. S. Varner; D. Walz; F. Wu

2010-01-01

356

Ultra short pulse generation and reshaping using highly nonlinear fibers  

NASA Astrophysics Data System (ADS)

We experimentally investigate the generation of a low-noise ultra short pulse train from 40GHz to160GHz by using Comb-like profiled fiber (CPF) for adiabatic soliton conversion and compression. Highly nonlinear fibers allow us to reduce total length of CPF as well as to utilize Kerr effect in the fiber effectively. We demonstrate generations of 160GHz soliton train of 750fs, the compression to 500fs of 40GHz externally-modulated pulse with wideband tunability over 30nm. Then we apply the CPF pulse compression technique to achieve the programmable repetition tunability from 5 to 500 MHz in low pedestral 300fs pulse train generation.

Matsushita, S.; Namiki, S.; Inoue, T.; Oguri, A.; Akutsu, T.; Shinozaki, J.; Ozeki, Y.; Takasaka, S.; Igarashi, K.; Sakano, M.; Yagi, T.

2005-11-01

357

Energy Savings by Wideband Temperature Control in Telephone Offices  

E-print Network

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

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

1983-01-01

358

Ultra-broadband terahertz metamaterial absorber  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

359

Wireless Andrew.  

ERIC Educational Resources Information Center

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

Fickes, Michael

2000-01-01

360

DISS. ETH NO. 18959 Ultra-Low Power Sensor Networks  

E-print Network

DISS. ETH NO. 18959 Ultra-Low Power Sensor Networks: Development Tools, Design, and Implementation Wattenhofer, examiner Prof. Jochen Schiller, co-examiner 2010 #12;#12;Abstract Wireless Sensor Networks (WSN for sensor networks. The thesis is organized in two orthogonal parts. The first part is dedicated

361

Wideband fractal antennas for holographic imaging and rectenna applications  

Microsoft Academic Search

At Pacific Northwest National Laboratory, wideband antenna arrays have been successfully used to reconstruct three-dimensional images at microwave and millimeter-wave frequencies. Applications of this technology have included portal monitoring, through-wall imaging, and weapons detection. Fractal antennas have been shown to have wideband characteristics due to their self-similar nature (that is, their geometry is replicated at different scales). They further have

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

2008-01-01

362

Wireless Communication  

NSDL National Science Digital Library

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

Van Zeghbroeck, Bart Jozef

363

Wideband digital low-frequency radio receiver  

NASA Astrophysics Data System (ADS)

A wideband digital low-frequency radio receiver for scientific applications is described. The portable battery-powered instrument has the capability to record electric field strengths in the frequency range from ~4 Hz to ~400 kHz with a sampling frequency of 1 MHz, an amplitude resolution of ~35 µV and a timing accuracy of ~12 ns whilst performing continuous digital waveform recordings for several days. The instrument strictly follows a modular design such that it can be extended to higher frequencies and timing accuracy when the corresponding digital technology becomes available. The low-cost radio receiver can be developed into an interferometric network by synchronizing individual radio receivers to map the low-frequency radio sky. The first measurements of atmospheric electric fields are carried out at Exmoor National Park in Southwest England to illustrate the capabilities of the novel instrument.

Füllekrug, M.

2010-01-01

364

Decentralized Output-only Modal Identification Techniques for Wireless Monitoring Systems  

E-print Network

performance during due diligence in real estate transactions. Within the field of SHM, wireless sensors have of the most promising. With the recent advancement of low-cost and ultra-compact wireless sensing and data in a controlled manner is difficult, especially when the size of the structure increases. Therefore, output

Lynch, Jerome P.

365

In-chip fast frequency hopped and direct sequence CDMA systems for indoor wireless communications  

Microsoft Academic Search

A novel hybrid fast frequency hopping (FFH) and direct sequence (DS) code division multiple access (CDMA) scheme for indoor wireless communications is proposed and analyzed. Bit error rate performance of this hybrid system is compared with that of a wide-band DS-CDMA system and a DS-CDMA system with frequency diversity transmission occupying the same bandwidth. The proposed scheme does not require

Masato Mizoguchi; Kazuhiko Seki

1996-01-01

366

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

E-print Network

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

Shubitidze, Fridon

367

RANGE AND BEARING ESTIMATION OF WIDEBAND SOURCES USING AN ORTHOGONAL BEAMSPACE PROCESSING STRUCTURE  

E-print Network

RANGE AND BEARING ESTIMATION OF WIDEBAND SOURCES USING AN ORTHOGONAL BEAMSPACE PROCESSING STRUCTURE National University Canberra ACT 0200, Australia ABSTRACT We propose a new method for range and bearing wideband sources, making it ideal for wideband range and bearing estimation. Performance of the estimator

Abhayapala, Thushara D.

368

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

E-print Network

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

Bellan, Paul M.

369

Dual-Mode Wideband Speech Recovery from Narrowband Speech Yasheng Qian Peter Kabal  

E-print Network

Dual-Mode Wideband Speech Recovery from Narrowband Speech Yasheng Qian Peter Kabal Department speech transmitted in current public tele- phone networks is bandpass-filtered to 300­3400 Hz. The filter at the interface between newer wideband systems and conventional narrowband systems is to generate wideband speech

Kabal, Peter

370

Design of multi-channel wireless NoC to improve on-chip communication capacity!  

Microsoft Academic Search

Many-core chip design has become a popular means to sustain the exponential growth of chip-level computing performance. The main advantage lies in the exploitation of parallelism, distributively and massively. Consequently, the on-chip communication fabric becomes the performance determinant. In the meantime, the intro- duction of Ultra-Wideband (UWB) interconnect brings in the new opportunity for giga-bps communication bandwidth, milliwatts com- munication

Dan Zhao; Yi Wang; Jian Li; Takamaro Kikkawa

2011-01-01

371

Wideband Interferometric Sensing and Imaging Polarimetry  

NASA Technical Reports Server (NTRS)

Wideband Interferometric Sensing and Imaging Polarimetry (WISIP) has become an important, indispensible tool in wide area military surveillance and global environmental monitoring of the terrestrial and planetary covers. It enables dynamic, real time optimal feature extraction of significant characteristics of desirable targets and/or target sections with simultaneous suppression of undesirable background clutter and propagation path speckle at hitherto unknown clarity and never before achieved quality. WISIP may be adopted to the detection, recognition, and identification (DRI) of any stationary, moving or vibrating targets or distributed scatterer segments versus arbitrary stationary, dynamical changing and/or moving geo-physical/ecological environments, provided the instantaneous 2x2 phasor and 4x4 power density matrices for forward propagation/backward scattering, respectively, can be measured with sufficient accuracy. For example, the DRI of stealthy, dynamically moving inhomogeneous volumetric scatter environments such as precipitation scatter, the ocean/sea/lake surface boundary layers, the littoral coastal surf zones, pack ice and snow or vegetative canopies, dry sands and soils, etc. can now be successfully realized. A comprehensive overview is presented on how these modern high resolution/precision, complete polarimetric co-registered signature sensing and imaging techniques, complemented by full integration of novel navigational electronic tools, such as DGPS, will advance electromagnetic vector wave sensing and imaging towards the limits of physical realization. Various examples utilizing the most recent image data take sets of airborne, space shuttle, and satellite imaging systems demonstrate the utility of WISIP.

Verdi, James Salvatore; Kessler, Otto; Boerner, Wolfgang-Martin

1996-01-01

372

Wireless services business plan  

E-print Network

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

Koh, Bong (Bong Dug)

2005-01-01

373

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

374

Embedded wireless strain sensors based on printed RFID tag  

Microsoft Academic Search

Purpose – The purpose of this paper is to develop a wireless strain sensor for measuring large strains. The sensor is based on passive ultra high-frequency radio frequency identification (RFID) technology and it can be embedded into a variety of structures. Design\\/methodology\\/approach – Silver ink conductors and RFID tags were printed by the screen printing method on stretchable polyvinyl chloride

Sari Merilampi; Toni Björninen; Leena Ukkonen; Pekka Ruuskanen; Lauri Sydänheimo

2011-01-01

375

Multireflection modal method for wideband fused-silica transmission gratings.  

PubMed

A multireflection modal method is proposed to give a clear physical picture for explanation of the diffraction process that takes place in a wideband fused-silica transmission grating. Using rigorous coupled-wave analysis, the optimized grating exhibits diffraction efficiency greater than 93.9% for TE polarization over a bandwidth of 126 nm (from 735 to 861 nm). The designed wideband fused-silica transmission grating is fabricated using holographic interference recording and inductively coupled plasma etching technology. Experimental results are in agreement with the theoretical values. PMID:23669691

Sun, Wenting; Lv, Peng; Zhou, Changhe; Cao, Hongchao; Wu, Jun

2013-04-20

376

A multiprocessor channel scheduler for the Wideband Packet Satellite network  

NASA Astrophysics Data System (ADS)

The Wideband (Packet Satellite) network is an experimental 3 Mb/s communication system used to evaluate the utilization of satellite packet switching for efficient voice transmission, voice conferencing, and the integration of voice, image, and data transmission. The Pluribus Satellite Interface Message Processor (PSAT) is responsible for the management of the wideband network satellite channel as well as for interfacing of host subscribers. The services supported by the PSAT are described, and an overview of the PSAT algorithms, hardware, and software is presented.

Falk, G.; Groff, S.; Milliken, W.; Nodine, M.; Blumenthal, S.; Edmond, W.

377

Narrowband and wideband characterisation of satellite mobile/PCN channel  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

378

Frequency-aware rate adaptation and MAC protocol  

E-print Network

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

Rahul, Hariharan Shankar

379

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

E-print Network

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

Celik, Guner Dincer

2007-01-01

380

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

NASA Astrophysics Data System (ADS)

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

Sharma, Vijay; Sharma, M. M.

2014-01-01

381

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

382

Computer Modeling of Wideband Quad-Ridge Horn  

E-print Network

Modeling is discussed using QuickWave and CST Microwave Studio. In addition, several external.1.3 Problems, Difficulties, and Errors 22 2.2 CST Microwave Studio 23 2.2.1 Features 23 2.2.2 Basic UsageComputer Modeling of Wideband Quad-Ridge Horn Microwave Antenna Feeds Gabe A. Cohn RF and Microwave

Weinreb, Sander

383

Wideband channel modelling in UHF band for urban area  

Microsoft Academic Search

This paper studies the small-scale multipath propagation characteristics of a typical outdoor urban environment. Wideband channel sounding measurements are performed and findings are presented. Channel sounding is carried out at UHF band (250, 300, 350, 400 MHz) for static transmit and receive antennas. The power delay profile, mean delay spread, RMS delay spread, as well as coherence bandwidth have been

Xiaohong Mao; Yee Hui Lee; Boon Chong Ng

2008-01-01

384

WIDEBAND BOW-TIE SLOT ANTENNA WITH TUNING STUBS  

E-print Network

WIDEBAND BOW-TIE SLOT ANTENNA WITH TUNING STUBS Abdelnasser A. Eldek, Atef Z. Elsherbeni Senior, USA Abstract Printed bow-tie and bow-tie slot antennas are planar-type variations of the biconical stub to a bow-tie slot antenna design to enhance the antenna bandwidth for X-band operation. Our study

Elsherbeni, Atef Z.

385

Wide-band array signal processing via spectral smoothing  

NASA Technical Reports Server (NTRS)

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

Xu, Guanghan; Kailath, Thomas

1989-01-01

386

Wideband enhancement of television images for people with visual impairments  

E-print Network

Wideband enhancement of television images for people with visual impairments Eli Peli The Schepens of the image. Testing with static television images revealed that visually impaired patients (n 35) could.4060, 330.5510. 1. INTRODUCTION A growing number of people suffer from visual impair- ments

Peli, Eli

387

An electromagnetic micro power generator for wideband environmental vibrations  

Microsoft Academic Search

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

Ibrahim Sari; Tuna Balkan; Haluk Kulah

2008-01-01

388

Uniplanar Wideband Quasi Yagi Antenna for Multiple Antenna Channel Measurements  

E-print Network

of arrival information, and data necessary for the design of smart antennas and spectrally efficient systemsUniplanar Wideband Quasi Yagi Antenna for Multiple Antenna Channel Measurements M. Abdalla and S antenna has gained considerable attention recently as a method of producing a broad bandwidth antenna

Haddadi, Hamed

389

Wide-band negative permeability of nonlinear metamaterials  

E-print Network

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

390

Cylindrical lens-array antenna for wideband electronic scanning  

Microsoft Academic Search

This report describes the fabrication and testing of a lens antenna that is designed to have wideband scanning capabilities for wide angle scanning in any plane. The lens has a 30 by 40 wavelength aperture. Far field patterns were measured in both azimuth and elevation planes over and eleven percent bandwidth. The azimuth scan angles were 0 deg, 15 deg,

E. M. Newman; C. M. Ruskowski

1985-01-01

391

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

392

PSEUDO-WIDEBAND SPEECH RECONSTRUCTION FROM TELEPHONE SPEECH  

E-print Network

in a number of ways from the narrowband residual of an LP (Linear Prediction) filter. The highband excitation Frequency (LSF) VQ codebook mapping from the narrowband speech to the high frequency components, the extra quality will be lost in the connection to the existing narrowband PSTN. Pseudo-wideband expansion

Kabal, Peter

393

Simple phenomenological models for wideband frequency-domain electromagnetic induction  

Microsoft Academic Search

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

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

2001-01-01

394

Hardware Modeling and Machining for UAV Based Wideband Radar  

Microsoft Academic Search

The Center for Remote Sensing of Ice Sheets (CReSIS) at the University of Kansas is currently implementing wideband radar systems and other sensors that can obtain ice profiling data from Polar Regions using airborne platforms. In particular a 180-220 MHz radar is being developed to operate on the Unmanned Aerial Vehicle (UAV). The UAV has been given the name \\

Ryan Tubbs

395

Efficient wideband source localization using beamforming invariance technique  

Microsoft Academic Search

A novel scheme for wideband direction-of-arrival (DOA) estimation is proposed. The technique performs coherent signal subspace transformation by a set of judiciously constructed beamforming matrices. The beamformers are chosen to transform each of the narrowband array manifold vectors into the one corresponding to the reference frequency, regardless of the actual spatial distribution of the sources. The focused data correlation matrix

Ta-Sung Lee

1994-01-01

396

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

397

Wide-band gas leak imaging detection system using UFPA  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

398

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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

Fred Sabins

2001-07-18

399

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

E-print Network

in the presence of impulsive interference. We introduced optimal, maximum likelihood-based approaches-order statistics and introduced the ROC-MUSIC algorithm for array processing ap- plications where reduced of wide-band sources in impulsive noise environments. Focused wide-band methods are used so that broad

Tsakalides, Panagiotis

400

Wideband S-parameter characterization of DC-SQUID amplifiers at GHz frequencies  

NASA Astrophysics Data System (ADS)

Superconducting quantum interference devices (SQUIDs) are widely used as gain elements to achieve ultra-low noise amplification from DC to microwave frequencies. SQUID amplifiers typically have high input and output stray reactance and therefore proper impedance matching is needed to couple enough power into the device. Broadband impedance matching could be obtained by measuring the microwave S-parameters of a SQUID amplifier and then treating it as an equivalent ``black box'' to which standard microwave design techniques can be applied. In this talk measurement results of the full 2-port S-parameter matrix of DC-SQUID amplifiers operating at 20mK will be presented. Accurate microwave calibration was performed with an automated Through-Reflect-Line (TRL) calibration system, operating at 20mK. Input and output reflection coefficients as well as forward and backward transmission were characterized in the 1 to 8GHz range. Implications for the design of wideband SQUID amplifiers and device stability will be discussed.

Ranzani, Leonardo; Spietz, Lafe; Aumentado, Jose

2012-02-01

401

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

PubMed Central

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

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

2013-01-01

402

Capacity of UWB wireless channel for neural recording systems.  

PubMed

Ultra wide-band (UWB) short-range communication systems are valuable in medical technology, particularly for implanted devices, due to their low-power consumption, low cost, small size and high data rates. Monitoring of neural responses in the brain requires high data rate if we target a system supporting a large number of sensors. In this work, we are interested in the evaluation of the capacity of the ultra wide-band (UWB) channel that we could exploit using a realistic model of the biological channel. The channel characteristics are examined under two scenarios that are related to TX antenna placements. Using optimal power spectrum allocation (OPSA) at the transmitter side, we have computed this capacity by taking into account the fading characteristics of the channel. The results show the pertinence of the optimal power spectrum allocation for this type of channel. An improvement by a factor of 2 to 3 over a uniform power spectrum allocation (UPSA) when the SNR <; 0 dB was obtained. When the SNR is > 40 dB, both approaches give similar results. Antennas placement is examined under two scenarios having contrasting power constraints. PMID:25570860

El Khaled, Mohamad; Bahrami, Hadi; Fortier, Paul; Gosselin, Benoit; Rusch, Leslie Ann

2014-08-01

403

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

NASA Astrophysics Data System (ADS)

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

Buckley, Brandon Walter

404

Time-domain imaging of radar targets using ultra-wideband or short pulse radars  

NASA Astrophysics Data System (ADS)

The development of viable short-pulse radar system has renewed the interest in time domain imaging performed directly in time-domain with temporally measured signal. Since the short-pulse response of a target provides significant information about the positions and strengths of scattering centers, and if observations are made over a wide range of aspect angle, one might create an image of the target using the short-pulse response information. In this thesis, we have developed and implemented a time-domain radar imaging technique based on a space-time magnetic field integral equation, using a sine modulated exponential pulse, and employing the inverse Radon transform. Images of various aircraft models were created from measured target responses over a wide band of frequencies and over the entire range of aspect angles. For the limited-view problem, two techniques have been proposed to process this practical situation. One of the approaches is the method of projections onto convex sets (POCS) which has been used in image processing for a long time. We extend this approach to radar imaging for the first time and show some useful results. Another approach which we have demonstrated is to process the available measured projections in order to generate an estimate of the full set of projections, an image which is called a sinogram. The goal of this approach is to recover the sinogram from the available measured data using linear prediction. Since the scattered field of a target can be written as a superposition of distinct specular reflection arising from scattering centers on the target, the position and strength of the scattering centers can be predicted using linear prediction with the change of the observation angle. Thus the missing data can be predicted before reconstructing the image. In the imaging of complex radar target, the PO approximation is used in the reconstruction algorithm. However, the PO approximation is inadequate for scattering problems of a complex shaped conducting object such as aircraft. At high frequency, edge diffractions, multiple reflections, creeping waves, and surface travelling waves may also be important scattering mechanisms. Additionally, the spectral and angular windows for data are usually restricted by practical constraints. Therefore the time domain image of a aircraft may be different from their geometrical shape. We have investigated time domain imaging of aircraft employing SMEP responses, and interpret the reconstructed image from a new approach, based on analysis of the scattering mechanisms and the back-projection algorithm utilized in image retrieval. The time-domain inverse scattering identity with the incorporation of Geometrical Theory of Diffraction (GTD) is derived and some interesting experimental results are provided.

Dai, Yingcheng

405

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

406

CMOS Integrated Circuit Design for Ultra-Wideband Transmitters and Receivers  

E-print Network

compared to previously published design while keep relatively high gain and low noise at the same time. The designed sampling mixer shows unprecedented performance of 9-12dB voltage conversion gain, 16-25dB noise figure, and power consumption of only 21.6m...

Xu, Rui

2010-10-12

407

Ultra-Wideband Mitigation of Simultaneous Switching Noise Using Novel Planar Electromagnetic Bandgap Structures  

Microsoft Academic Search

A novel design of power\\/ground plane with planar electromagnetic bandgap (EBG) structures for suppressing simultaneous switching noise (SSN) is presented. The novel design is based on using meander lines to increase the effective inductance of EBG patches. A super cell EBG structure, comprising two different topologies on the same board, is proposed to extend the lower edge of the band.

Jie Qin; Omar M. Ramahi

2006-01-01

408

Ultra-Wideband, Dual-Polarized, Beam-Steering P-Band Array Antenna  

NASA Technical Reports Server (NTRS)

A dual-polarized, wide-bandwidth (200 MHz for one polarization, 100 MHz for the orthogonal polarization) antenna array at P-band was designed to be driven by NASA's EcoSAR digital beam former. EcoSAR requires two wide P-band antenna arrays mounted on the wings of an aircraft, each capable of steering its main beam up to 35deg off-boresight, allowing the twin radar beams to be steered at angles to the flight path. The science requirements are mainly for dual-polarization capability and a wide bandwidth of operation of up to 200 MHz if possible, but at least 100 MHz with high polarization port isolation and low cross-polarization. The novel design geometry can be scaled with minor modifications up to about four times higher or down to about half the current design frequencies for any application requiring a dual-polarized, wide-bandwidth steerable antenna array. EcoSAR is an airborne interferometric P-band synthetic aperture radar (SAR) research application for studying two- and three-dimensional fine-scale measurements of terrestrial ecosystem structure and biomass, which will ultimately aid in the broader study of the carbon cycle and climate change. The two 2×8 element Pband antenna arrays required by the system will be separated by a baseline of about 25 m, allowing for interferometry measurements. The wide 100-to- 200-MHz bandwidth dual-polarized beams employed will allow the determination of the amount of biomass and even tree height on the ground. To reduce the size of the patches along the boresight dimension in order to fit them into the available space, two techniques were employed. One technique is to add slots along the edges of each patch where the main electric currents are expected to flow, and the other technique is to bend the central part of the patch away from the ground plane. The latter also facilitates higher mechanical rigidity. The high port isolation of more than 40 dB was achieved by employing a highly symmetrical feed mechanism for each pair of elements: three apertures coupling to the patch elements were placed along the two symmetry lines of the antenna element pair. Two apertures were used in tandem to excite two of the stacked patch elements for one polarization; the other was used to excite one element from one side and the other element from the other side, opposite in phase, taking care of the remaining polarization. The apertures narrow down to a small gap where they are excited by a crossing microstrip line to prevent any asymmetrical excitation of the two sides of the aperture gap, minimizing port-to-port coupling. Using patches that are non-planar leads to higher mechanical rigidity and smaller patch sizes to fit into the available space. Aperture coupling minimizes direct metal-to-metal connections. Using an aperture coupling feed mechanism results in a feed network for two antenna elements with a total of three feed points, plus one simple in-phase combiner to reduce it to two ports. It greatly reduces the complexity of the alternative, but more conventional, way of feeding a pair of two dual-polarized elements with high port isolation.

duToit, Cornelis

2014-01-01

409

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

410

Progress In Electromagnetics Research, Vol. 121, 121139, 2011 LOW-PROFILE DIRECTIONAL ULTRA-WIDEBAND AN-  

E-print Network

is presented. The antenna can be fabricated on a printed circuit board (PCB). On one side of the PCB, it has wavelength at the lowest frequency). In order to validate the design, a prototype is also fabricated at Vil- lanova University. A real-time see-through-wall radar system [8] based on FPGA is designed

Doran, Simon J.

411

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

E-print Network

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

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

2014-01-01

412

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

E-print Network

a video detection system in a test at a crossing in Maywood, Illinois. If the test is successful According to statistics compiled during 1994 by the Federal Railroad Administration, 610 people were killed or that they can beat the train. One method being studied by the railroad industry to stop these drive

Kansas, University of

413

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

E-print Network

and receiver respectively for timing control. A novel integrated CSH (Coupled-Slotline Hybrid)sampling mixer has been developed along with the design of the strobe pulse generator appropriate for the impulse radar system. The integrated sampling mixer has...

Han, Jeongwoo

2006-08-16

414

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

DOEpatents

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

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

2012-01-24

415

Ultra-wideband amplifiers based on Bi 2O 3-EDFAs  

NASA Astrophysics Data System (ADS)

We demonstrate broadband amplification over (C?+?L)-band or extended L-band using fusion-spliceable Bi 2O 3-based erbium doped fiber (EDF). A power conversion efficiency (PCE) of 39% is achieved. In a single-stage amplifier we achieved a 3 dB bandwidth of 75 nm. In addition we showed very low four-wave mixing in an extended L-band amplifier by reducing the length of fiber required to a few meters.

Ohara, S.; Sugimoto, N.; Ochiai, K.; Hayashi, H.; Fukasawa, Y.; Hirose, T.; Nagashima, T.; Reyes, M.

2004-10-01

416

An Ultra-Wideband Receiver and Spectrometer for 74--110 GHz  

NASA Astrophysics Data System (ADS)

A receiver system that covers the widest instantaneous bandwidth ever utilized by an astronomical heterodyne receiver is nearly complete. The entire 74--110.5 GHz band will be covered with a low noise frontend and a backend spectrometer having 31 MHz resolution. The receiver is intended for astronomical use in searching for the highly redshifted spectral lines from galaxies of unknown redshift. The receiver uses InP MMIC based low noise amplifiers operated at 20 K, and operates with dual polarization feeds. The two receivers used with each feed are combined using a full band orthomode transition. Two such feeds are used in conjunction with a beam switch to maintain one dual polarized beam on the source at all times. The backend spectrometer is an analog autocorrelator built using very low cost microwave and analog/digital components.

Erickson, N.; Narayanan, G.; Goeller, R.; Grosslein, R.

2007-10-01

417

Photonic generation of ultra-wideband monocycle and doublet pulses using simplex semiconductor optical amplifier  

NASA Astrophysics Data System (ADS)

We demonstrate two all-optical methods for UWB pulse generation based on various nonlinearities of the semiconductor optical amplifier (SOA), namely, self phase modulation (SPM), and cross gain modulation (XGM). In the first method, we present UWB doublet generation based on SPM. The monocycle pulse is generated from dark return-to-zero (RZ) signal, and then converted to doublet pulse by injecting an additional probe signal with the SMF transmission. For the first time to best of our knowledge, we report that the generated doublet pulses are transmitted over 5km SMF by proper dispersion compensation without distortion. Second, we present UWB doublet generation by XGM of two cascaded SOAs. The configuration of our all-optical methods is compact and simple.

Dong, Jianji; Zhang, Xinliang; Huang, Dexiu; Zhou, Enbo

2008-11-01

418

Progress towards ultra-wideband AlGaN/GaN MMICs  

NASA Astrophysics Data System (ADS)

The AlGaN/GaN material system possesses fundamental properties that make it an ideal candidate for high power microwave devices. This has been known for over 30 years, however, significant device progress has only come recently. This article gives a summary of AlGaN/GaN electronic device progress, outlines future device directions, and discusses the use of these new devices in power amplifier circuits.

Zolper, J. C.

1999-08-01

419

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

420

An analog approach to interference suppression in ultra-wideband receivers  

E-print Network

. The Operational Transconductance Amplifier (OTA) is the predominant building block in the design of the notch filter. In many cases, OTAs must handle input signals with large common mode swings. A new scheme for achieving rail-to-rail input to an OTA is introduced...

Fischer, Timothy W.

2007-09-17

421

Impulse Radio Ultra-Wideband Communication Over Free-Space Optical Links  

E-print Network

. The elements of the input Gaussian pulse train are first phase modulated by a high-speed electro-optical phase]. The UWB pulses are directly gener- ated in the optical domain by the use of a high-speed electro- optic to achieve very high data rates, however, due to the low power requirement and the severe multipath

Deliç, Hakan

422

Time Reversal with MISO for Ultra-Wideband Communications: Experimental Results (invited paper)  

E-print Network

, control of home appliances, search-and-rescue, family communications and supervision of children with the channel impulse response (CIR) (from Rx to Tx), , at the m-th transmitter antenna. Second, the ( )f t x

Qiu, Robert Caiming

423

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

SciTech Connect

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

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

2013-11-14

424

Generic z-domain discrete-time transfer function estimation for ultra-wideband  

E-print Network

regime based upon prolate spheroidal wave functions (PSWFs) [3] is employed for transmitting the UWB-PSWF) and equating it with (5) we obtain the value for bl with UWB-PSWF pulse duration and energy T and E

Chen, Sheng

425

Multiband Orthogonal PSWF Pulses Used for Mary PPM Ultra-Wideband System  

Microsoft Academic Search

In this paper, we proposed a multiband orthogonal PSWF pulse set design method. The designed pulse set has a high spectrum utilization efficiency while meeting the FCC spectral mask without frequency shifting or additional filtering. Based on this, a Mary PPM modulation scheme using the orthogonal pulse set is developed. In this scheme each user is assigned a different orthogonal

Hou Wen-jun; Wang Hong-xing

2011-01-01

426

Analysis and Design of a CMOS UWB LNA With Dual Branch Wideband Input Matching Network  

Microsoft Academic Search

A wideband low-noise amplifier (LNA) based on the current-reused cascade configuration is proposed. The wideband input-impedance matching was achieved by taking advantage of the resistive shunt-shunt feedback in conjunction with a parallel LC load to make the input network equivalent to two parallel RLC-branches, i.e., a second-order wideband bandpass filter. Besides, both the inductive series- and shunt-peaking techniques are used

Yo-Sheng Lin; Chang-Zhi Chen; Hong-Yu Yang; Chi-Chen Chen; Jen-How Lee; Guo-Wei Huang; Shey-Shi Lu

2010-01-01

427

Direction Dependent Effects In Widefield Wideband Full Stokes Radio Imaging  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

428

THz radiation using high power, microfabricated, wideband TWTs  

Microsoft Academic Search

Microfabricated, miniature, folded waveguide traveling wave tube (FWG-TWT) devices are potential compact sources of wideband (~20% instantaneous bandwidth), high power (0.01-1 W) THz radiation. We present theoretical analyses and numerical simulations indicating that a 560 GHz, 56 mW, 1% (intrinsic) efficiency oscillator is realistically achievable, and amplifiers with gains between 10 and 30 dB are feasible with circuit lengths of

C. L. Kory; J. H. Booske; W.-J. Lee; S. Gallagher; D. W. van der Weide; S. Limbach; S. Bhattacharjee

2002-01-01

429

Asymptotic Behavior of Error Exponents in the Wideband Regime  

Microsoft Academic Search

Abstract In this paper, we complement Verd´ u’s work on spectral effici ency in the wideband regime by investigating the fundamental,tradeoff between,rate and bandwidth,when,a constraint is imposed,on the error exponent. Specifically, we consider both AWGN and Rayleigh-fading cha nnels where the input symbols are assumed to have a peak constraint. For the AWGN channel model, the optimal values of Rz(0)

X. Wu; R. Srikant

2005-01-01

430

Mask Programmable CMOS Transistor Arrays for Wideband RF Integrated Circuits  

Microsoft Academic Search

A mask programmable technology to implement RF and microwave integrated circuits using an array of standard 90-nm CMOS transistors is presented. Using this technology, three wideband amplifiers with more than 15-dB forward transmission gain operating in different frequency bands inside a 4-22-GHz range are implemented. The amplifiers achieve high gain-bandwidth products (79-96 GHz) despite their standard multistage designs. These amplifiers

Laleh Rabieirad; Edgar J. Martinez; Saeed Mohammadi

2009-01-01

431

Performance of power-controlled wideband terrestrial digital communication  

Microsoft Academic Search

Performance of a wideband multipath-fading terrestrial digital coded communication system is treated. The analysis has applications to a cellular system using direct-sequence spread-spectrum code-division multiaccess (CDMA) with M-ary orthogonal modulation on the many-to-one reverse (user-to-base station) link. For these links, power control of each multiple-access user by the cell base station is a critically important feature. This feature is implemented

Andrew J. Viterbi; Audrey M. Viterbi; Ephraim Zehavi

1993-01-01

432

Enhanced Coupling Structures for Tight Couplers and Wideband Filters  

Microsoft Academic Search

Tightly coupled lines are difficult to realize on the conventional printed circuit board (PCB). This paper proposes two types of novel enhanced coupled-line structures appropriate for tightly coupled directional couplers and wideband filters. The proposed coupled-line structures both have a rectangular ground-plane aperture and two inserted signal strips in the aper- ture to increase the coupling strength significantly. No fine

Cheng-Hsien Liang; Wei-Shin Chang; Chi-Yang Chang

2011-01-01

433

Adaptive target tracking for wideband sources in near field  

Microsoft Academic Search

A novel adaptive signal subspace transformation for direction-of-arrival (DOA) estimation of wideband sources in the near-field is proposed in this paper. The method is composed of two transformations: signal subspace focusing (SSF) and far-field transform (FFT). SSF aligns the signal subspaces for different frequencies in the bandwidth of the sources based on focusing matrices. FFT transforms the near-field steering vector

Lena Chang; Ching-Min Cheng

2009-01-01

434

A wireless sensor enabled by wireless power.  

PubMed

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

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

2012-01-01

435

A Wireless Sensor Enabled by Wireless Power  

PubMed Central

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

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

2012-01-01

436

Performance Evaluation of Different Modulation Schemes for Ultra Wide Band Systems  

NASA Astrophysics Data System (ADS)

Ultra-wideband (UWB) signals with a large bandwidth has some advantages like multipath immunity, low transmission power, good resolution for ranging and detecting geo locations, as well as it can resist to narrow-band interference. These signals are used for transmission in short distance with high throughput. In this paper, we have analyzed different modulation schemes for performance comparison in terms of BER with UWB Gaussian second derivative monopulse and wavelet-based monopulse. The simulation results demonstrate that wavelet-based monopulse provides better performance in comparison to the other two monopulses.

Ali, Tasnuva; Siddiqua, Poppy; Matin, Mohammad A.

2014-05-01

437

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

E-print Network

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

Powell, Johnna, 1980-

2009-01-01

438

Design of a wideband excitation source for fast bioimpedance spectroscopy  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

439

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

440

Adaptive Beam Steering Smart Antenna System for Ultra-High-Frequency Radio Frequency Identification Applications  

Microsoft Academic Search

Smart antenna technologies have been widely applied in many wireless communication systems due to performance enhancement in terms of data range, coverage and capacity. Up to now, not much effort was devoted for ultra high-frequency (UHF) radio frequency identification (RFID) applications mainly due to the relatively large size of the antenna element. In this paper, we present a compact-sized electrically

Ting-Jui Huang; Pei-Hsuan Pan; Heng-Tung Hsu

2012-01-01

441

High performance wireless Ethernet  

Microsoft Academic Search

This article considers the IEEE 802.11b standard for high-performance wireless Ethernet and a proposed extension that provides for 22 Mb\\/s transmission. The IEEE 802.11 sets standards for wireless Ethernet or wireless local area networks. The article describes the history of the IEEE 802.11 standards and the market opportunities in the wireless Ethernet field. The article gives a brief description of

C. Heegard; J. T. Coffey; S. Gummadi; P. A. Murphy; R. Provencio; E. J. Rossin; S. Schrum; M. B. Shoemake

2001-01-01

442

Miniaturized wireless ECG-monitor for real-time detection of epileptic seizures  

Microsoft Academic Search

Recent advances in miniaturization of ultra-low power components allow for more intelligent wearable health monitors. Such systems may be used in a wide range of application areas. Here, the development and evaluation of a wireless wearable electrocardiogram (ECG) monitor to detect epileptic seizures from changes in the cardiac rhythm is described. The ECG is measured using an ultra-low-power circuit for

Fabien Massé; Julien Penders; Aline Serteyn; Martien van Bussel; Johan Arends

2010-01-01

443

Community Wireless Networks  

ERIC Educational Resources Information Center

With increasing frequency, communities are seeing the arrival of a new class of noncommercial broadband providers: community wireless networks (CWNs). Utilizing the same wireless technologies that many colleges and universities have used to create wireless networks on campus, CWNs are creating broadband access for free or at costs well below…

Feld, Harold

2005-01-01

444

Performance of the THS4302 and the Class V Radiation-Tolerant THS4304-SP Silicon Germanium Wideband Amplifiers at Extreme Temperatures  

NASA Technical Reports Server (NTRS)

This report discusses the performance of silicon germanium, wideband gain amplifiers under extreme temperatures. The investigated devices include Texas Instruments THS4304-SP and THS4302 amplifiers. Both chips are manufactured using the BiCom3 process based on silicon germanium technology along with silicon-on-insulator (SOI) buried oxide layers. The THS4304-SP device was chosen because it is a Class V radiation-tolerant (150 kRad, TID silicon), voltage-feedback operational amplifier designed for use in high-speed analog signal applications and is very desirable for NASA missions. It operates with a single 5 V power supply [1]. It comes in a 10-pin ceramic flatpack package, and it provides balanced inputs, low offset voltage and offset current, and high common mode rejection ratio. The fixed-gain THS4302 chip, which comes in a 16-pin leadless package, offers high bandwidth, high slew rate, low noise, and low distortion [2]. Such features have made the amplifier useful in a number of applications such as wideband signal processing, wireless transceivers, intermediate frequency (IF) amplifier, analog-to-digital converter (ADC) preamplifier, digital-to-analog converter (DAC) output buffer, measurement instrumentation, and medical and industrial imaging.

Patterson, Richard L.; Elbuluk, Malik; Hammoud, Ahmad; VanKeuls, Frederick W.

2009-01-01

445

Synthesis of Higher-Order K-Delta-1-Sigma Modulators for Wideband ADCs  

E-print Network

). Therefore, the traditional delta-sigma ADCs can not achieve Nyquist-rate sampling as desired for wideband1 Synthesis of Higher-Order K-Delta-1-Sigma Modulators for Wideband ADCs Vishal Saxena, Student-to-digital converters (ADCs) in nano-CMOS processes. To move towards an ADC topology useful in nano-CMOS, the K-Delta-1

Baker, R. Jacob

446

Numerical Analysis Techniques for Wideband Amplifiers Namkyoo Park, Won Jae Lee, Bumki Min, and Jaehyoung Park  

E-print Network

1 Numerical Analysis Techniques for Wideband Amplifiers Namkyoo Park, Won Jae Lee, Bumki Min-doped fiber amplifiers (EDFA). With the intensive development efforts on new rare-earth dopants and fiber nonlinearity (Raman process) for fast few years, wideband optical amplifiers now can support easily over 4

Park, Namkyoo

447

Wideband Power Reflectance and Power Transmittance as Tools for Assessing Middle-Ear Function  

E-print Network

44 Wideband Power Reflectance and Power Transmittance as Tools for Assessing Middle-Ear Function using otoacoustic emissions can have high false positive rates, due to temporary middle-ear and outer-ear is limited, uncomfortable, and unreliable in young ears. By incorporating wideband acoustic power flow

Allen, Jont

448

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

ERIC Educational Resources Information Center

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

Burdiek, Laina M.; Sun, Xiao-Ming

2014-01-01

449

Bayesian sparse regularization in near-field wideband aeroacoustic imaging for wind tunnel test  

E-print Network

Bayesian sparse regularization in near-field wideband aeroacoustic imaging for wind tunnel test N. On simulated and wind tunnel data, proposed approach is compared with the beamforming, DAMAS, Diagonal Remove to investigate near-field wideband aeroacoustic imaging on vehicle surface in wind tunnel test based on the 2D

Paris-Sud XI, Université de

450

Planar Wideband Microstrip Antenna with Inclined Radiation Pattern for C-Band Airborne Applications  

E-print Network

Planar Wideband Microstrip Antenna with Inclined Radiation Pattern for C-Band Airborne Applicationsµm-thick substrate exhibits wideband performance and inclined radiation patterns. The measured ground plane microstrip patch antenna [1] and the printed Yagi array antenna [2]. However, the most

Paris-Sud XI, Université de

451

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

E-print Network

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

Kim, Sang Gyu

2005-08-29

452

Global wireless framework: one world wireless devices  

Microsoft Academic Search

We present the paradigm of using autoassigned predefined nonInternet routable IP addresses with mobile devices (global wireless framework) as the basis to provide services to nomadic end users in information spaces. As an example of how global wireless IP can be constructed as a base of services providing for personal mobility, we show working scenarios and protocols that are used

A. Mingkhwan; M. Merabti; B. Askwith

2002-01-01

453

Wideband direct conversion hybrid LCP millimeter-wave 4× subharmonic mixer for gigabit wireless module  

Microsoft Academic Search

In this paper, we describe the realization of highly integrated system-on-package (SOP) millimeter wave module on liquid crystal polymer (LCP). LCP provides an organic, low-cost, low dielectric constant platform suitable for mm-wave passive design and packaging. Here we firstly demonstrate 40GHz planar bandpass filter and RF\\/baseband duplexer as building blocks of the integrated module. ?3dB insertion loss and >6GHz RF

S. Sarkar; D. Yeh; S. Pinel; J. Laskar

2005-01-01

454

Wide-band microwave propagation parameters using circular and linear polarized antennas for indoor wireless channels  

Microsoft Academic Search

Results of experiments using a variety of antennas inside several buildings are presented. Path loss models for the 1.3 GHz and 4.0 GHz bands that show little difference in indoor path loss throughout the low-microwave region are discussed. Results show that line-of-sight (LOS) channels offer significantly more cross-polarization discrimination than obstructed channels. A profound result is that directional circularly polarized

Theodore S. Rappaport; Dwayne A. Hawbaker

1992-01-01

455

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

E-print Network

spacing) on AF beamwidth ..... 44 Figure 3.7 Illustration of the effect of N (number of elements) on scan angle ...... 46 Figure 4.1 4-element array design ......................................................................... 48 Figure 4...

Hansen, Jonathan Noel

2012-02-14

456

Wireless Corner Christos Christodoulou  

E-print Network

916248774 Fax: +34 916248749 E-mail: eva@tsc.uc3m.es Wideband Circularly Polarized E-Shaped Patch Antenna@olemiss.edu Abstract A new technique to achieve a circularly polarized probe-fed single-layer microstrip-patch antenna and compared with the recently proposed circularly polarized U-slot patch antennas. Keywords: Circular

Elsherbeni, Atef Z.

457

Wireless Sensors and Networks for Advanced Energy Management  

SciTech Connect

Numerous national studies and working groups have identified low-cost, very low-power wireless sensors and networks as a critical enabling technology for increasing energy efficiency, reducing waste, and optimizing processes. Research areas for developing such sensor and network platforms include microsensor arrays, ultra-low power electronics and signal conditioning, data/control transceivers, and robust wireless networks. A review of some of the research in the following areas will be discussed: (1) Low-cost, flexible multi-sensor array platforms (CO{sub 2}, NO{sub x}, CO, humidity, NH{sub 3}, O{sub 2}, occupancy, etc.) that enable energy and emission reductions in applications such as buildings and manufacturing; (2) Modeling investments (energy usage and savings to drive capital investment decisions) and estimated uptime improvements through pervasive gathering of equipment and process health data and its effects on energy; (3) Robust, self-configuring wireless sensor networks for energy management; and (4) Quality-of-service for secure and reliable data transmission from widely distributed sensors. Wireless communications is poised to support technical innovations in the industrial community, with widespread use of wireless sensors forecasted to improve manufacturing production and energy efficiency and reduce emissions. Progress being made in wireless system components, as described in this paper, is helping bring these projected improvements to reality.

Hardy, J.E.

2005-05-06

458

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

459

Optical multiple beam-forming systems for wireless communication antennas  

Microsoft Academic Search

Several new systems and concepts using optical technology are introduced for the wireless communication antenna. These include antenna-design limitations on frequency reuse in cellular architectures, optical beamforming, adaptive filtering, and direction finding, optical receive- mode IF combining, use of ultra-short optical time delay methods for millimeter wave antenna arrays, and the use of space-time coding of electro-optically steered lasers for

Nabeel A. Riza

1995-01-01

460

On the Accuracy of Localization Systems Using Wideband Antenna Arrays  

E-print Network

Accurate positional information is essential for many applications in wireless networks. Time-of-arrival (TOA) and angle-of-arrival (AOA) are the two most commonly used signal metrics for localizing nodes with unknown ...

Shen, Yuan

461

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. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

Fred Sabins

2003-01-31

462

Real-time wideband cylindrical holographic surveillance system  

DOEpatents

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

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

1999-01-01

463

Real-time wideband cylindrical holographic surveillance system  

DOEpatents

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 for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply Fast Fourier Transforms and obtain a three dimensional cylindrical image. 13 figs.

Sheen, D.M.; McMakin, D.L.; Hall, T.E.; Severtsen, R.H.

1999-01-12

464

Dendritic wideband metamaterial absorber based on resistance film  

NASA Astrophysics Data System (ADS)

A type of dendritic wideband metamaterial absorber was designed and constructed from resistance film composed of indium-tin oxide conductive film having a dendritic metamaterial structure, dielectric layer made of polymethacrylimide foam, and metallic sheet based on the equivalent circuit model. In terms of normal incidence, the simulation using the absorber yielded operating absorption rates >80 % in the frequency range of 8-27.9 GHz. In addition, the experimental measurements verified 8-17 GHz range of more than 80 % absorption rate, whereas its relative bandwidth reached 72 %. Moreover, this reasonable absorption performance was maintained for oblique incidences of <60°. The effects of dielectric layer thickness on absorption properties were verified.

Wang, Bing; Gong, Bo Yi; Wang, Mei; Weng, Bin; Zhao, Xiaopeng

2014-12-01

465

High load sensitivity in wideband infrared dual-Vivaldi nanoantennas.  

PubMed

Dual-Vivaldi nanoantenna (DVA) arrays were designed, fabricated, and optically characterized in the infrared (IR) and visible regimes. The antenna arrays were characterized by measuring the scattered light at IR (1450-1640 nm) and visible (780 nm) spectral ranges. The radiation efficiency and the spectral response of the antennas were found to be in good agreement with numerical simulations. The results presented here demonstrate the extremely wideband nature of the DVAs and the strong impact of load at the antenna terminals on its scattering response. These properties, as well as their many degrees of freedom for design, render the DVAs excellent candidates for optical sensing applications. PMID:23454963

Yifat, Yuval; Iluz, Zeev; Bar-Lev, Doron; Eitan, Michal; Hanein, Yael; Boag, Amir; Scheuer, Jacob

2013-01-15

466

A wide-band 760-GHz planar integrated Schottky receiver  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

467

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

PubMed

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

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

2009-01-01

468

Wideband Fractal Antennas for Holographic Imaging and Rectenna Applications  

SciTech Connect

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

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

2008-04-18

469

Digital orthogonal receiver for wideband radar based on compressed sensing  

NASA Astrophysics Data System (ADS)

Digital orthogonal receiver is one of the key techniques in digital receiver of soft radar, and compressed sensing is attracting more and more attention in radar signal processing. In this paper, we propose a CS digital orthogonal receiver for wideband radar which utilizes compressed sampling in the acquisition of radar raw data. In order to reconstruct complex signal from sub-sampled raw data, a novel sparse dictionary is proposed to represent the real-valued radar raw signal sparsely. Using our dictionary and CS algorithm, we can reconstruct the complex-valued radar signal from sub-sampled echoes. Compared with conventional digital orthogonal radar receiver, the architecture of receiver in this paper is more simplified and the sampling frequency of ADC is reduced sharply. At the same time, the range profile can be obtained during the reconstruction, so the matched filtering can be eliminated in the receiver. Some experiments on ISAR imaging based on simulated data prove that the phase information of radar echoes is well reserved in our orthogonal receiver and the whole design is effective for wideband radar.

Hou, Qingkai; Liu, Yang; Chen, Zengping; Su, Shaoying

2014-10-01

470

Gaussian beam and physical optics iteration technique for wideband beam waveguide feed design  

NASA Technical Reports Server (NTRS)

The Gaussian beam technique has become increasingly popular for wideband beam waveguide (BWG) design. However, it is observed that the Gaussian solution is less accurate for smaller mirrors (approximately less than 30 lambda in diameter). Therefore, a high-performance wideband BWG design cannot be achieved by using the Gaussian beam technique alone. This article demonstrates a new design approach by iterating Gaussian beam and BWG parameters simultaneously at various frequencies to obtain a wideband BWG. The result is further improved by comparing it with physical optics results and repeating the iteration.

Veruttipong, W.; Chen, J. C.; Bathker, D. A.

1991-01-01

471

Wideband antireflective circular polarizer exhibiting a perfect dark state in organic light-emitting-diode display.  

PubMed

We proposed wideband antireflective circular polarizer for realizing a true black state in all viewing directions in organic light-emitting-diode displays (OLEDs). Present commercialized wideband circular polarizer consisted of a half wave and a quarter wave plates having the refractive index parameter (Nz) of 1.5 in both films exhibits light leakage in the oblique viewing directions, deteriorating image quality of a black state. We evaluated Nzs of both films and proposed a new wideband antireflective circular polarizer with a perfect dark state in all viewing directions with Nz = 0.5 in both plates, which will greatly improve image quality of OLEDs. PMID:25607486

Kim, Bong Choon; Lim, Young Jin; Song, Je Hoon; Lee, Jun Hee; Jeong, Kwang-Un; Lee, Joong Hee; Lee, Gi-Dong; Lee, Seung Hee

2014-12-15

472

Feasibility of retroreflective transdermal optical wireless communication.  

PubMed

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

Gil, Yotam; Rotter, Nadav; Arnon, Shlomi

2012-06-20

473

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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

Fred Sabins

2001-01-15

474

Ultra-low-power wearable biopotential sensor nodes.  

PubMed

This paper discusses ultra-low-power wireless sensor nodes intended for wearable biopotential monitoring. Specific attention is given to mixed-signal design approaches and their impact on the overall system power dissipation. Examples of trade-offs in power dissipation between analog front-ends and digital signal processing are also given. It is shown how signal filtering can further reduce the internal power consumption of a node. Such power saving approaches are indispensable as real-life tests of custom wireless ECG patches reveal the need for artifact detection and correction. The power consumption of such additional features has to come from power savings elsewhere in the system as the overall power budget cannot increase. PMID:19964056

Yazicioglu, R F; Torfs, T; Penders, J; Romero, I; Kim, H; Merken, P; Gyselinckx, B; Yoo, H J; Van Hoof, C

2009-01-01

475

EM FULL-WAVE ANALYSIS AND TESTING OF NOVEL QUASI-ELLIPTIC MICROSTRIP FILTERS FOR ULTRA NARROWBAND FILTER DESIGN  

Microsoft Academic Search

Abstract—A new class of microstrip filter structures are designed, optimized, simulated and measured for ultra-narrowband performance essential to the wireless industry applications. More accurate model of the coupling coefficient is outlined and tested for narrowband filter design. Two sample filters are fabricated and measured to verify the simulations and prove the concept. The idea behind the new designs is based

Zuhair M. Hejazi; Maximilian C. Scardelletti; Frederick W. Van Keuls; Amjad A. Omar

2008-01-01

476

General clustering framework in wireless sensor networks.  

E-print Network

??The fast evolution of electronic technologies has foretold a promising and fancy future for wireless sensor network applications. Distinguished from typical wireless network, wireless sensor… (more)

Chen, Quanbin

2008-01-01

477

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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

Fred Sabins

2002-07-30

478

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

NASA Astrophysics Data System (ADS)

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

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

479

Improved Coronary MR Angiography Using Wideband SSFP at 3 Tesla with Sub-millimeter Resolution  

PubMed Central

Purpose To suppress off-resonance artifacts in coronary artery imaging at 3 Tesla, and therefore improve spatial resolution. Materials and Methods Wideband SSFP sequences utilize an oscillating steady state to reduce banding artifacts. Coronary artery images were obtained at 3T using three-dimensional navigated gradient echo, balanced SSFP, and wideband SSFP sequences. Results The highest in-plane resolution of left coronary artery images was 0.68 mm in the frequency-encoding direction. Wideband SSFP produced an average SNR efficiency of 70% relative to conventional balanced SSFP and suppressed off-resonance artifacts. Conclusion Wideband SSFP was found to be a promising approach for obtaining non-contrast, high-resolution coronary artery images at 3 Tesla with reliable image quality. PMID:20432360

Lee, Hsu-Lei; Shankaranarayanan, Ajit; Pohost, Gerald M.; Nayak, Krishna S.

2010-01-01

480

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

E-print Network

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

Valerdi, Ricardo

2011-06-20

481

Wideband monolithically integrated front-end subsystems and components  

NASA Astrophysics Data System (ADS)

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

Mruk, Joseph Rene

482

Wide-Band Microwave Receivers Using Photonic Processing  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

483

Fault Tolerance for Wireless Networks  

Microsoft Academic Search

Abstract—Wireless communcations and technology have estab- lished themselves as a ubiquitous facet of daily life. Mobile users have grown to depend on wireless technology in small portable computers, satellite communications, and wireless networks [1] establishing a need for wireless communications to operate in a robust and reliable manner. As part of a semester research effort, the topic of fault-tolerance for

Kevin M. Somervill

484

Warming Up to Wireless  

ERIC Educational Resources Information Center

In districts big and small across the U.S., students, teachers, and administrators alike have come to appreciate the benefits of wireless technology. Because the technology delivers Internet signals on airborne radio frequencies, wireless networking allows users of all portable devices to move freely on a school's campus and stay connected to the…

Milner, Jacob

2005-01-01

485

Specifying and calibrating instrumentations for wideband electronic power measurements. [in switching circuits  

NASA Technical Reports Server (NTRS)

The wideband electric power measurement related topics of electronic wattmeter calibration and specification are discussed. Tested calibration techniques are described in detail. Analytical methods used to determine the bandwidth requirements of instrumentation for switching circuit waveforms are presented and illustrated with examples from electric vehicle type applications. Analog multiplier wattmeters, digital wattmeters and calculating digital oscilloscopes are compared. The instrumentation characteristics which are critical to accurate wideband power measurement are described.

Lesco, D. J.; Weikle, D. H.

1980-01-01

486

HPM WBTS, a transportable high-power wide-band microwave source  

Microsoft Academic Search

HPM WBTS (High Power Microwave, Wide-Band Threat Systems) is a high power, repetitively pulsed, wide-band microwave generator. The HPM WBTS microwave capability covers the range of 200MHz to 6GHz in nine frequency bands. E- Field specification at target is 30-110 V\\/m\\/MHz depending on frequency. The system is transportable, capable of being set up at remote sites and operating on generator

D. Morton; J. Banister; T. DaSilva; J. Levine; T. Naff; I. Smith; H. Sze; T. Warren; D. V. Giri; C. Mora; J. Pavlinko; J. Schleher; C. E. Baum

2010-01-01

487

Planar wideband microstrip antenna with inclined radiation pattern for C-band airborne applications  

Microsoft Academic Search

This paper presents the design and experimental validation of an original single layer planar wideband microstrip antenna for C-band airborne applications. This antenna printed on a 787µm-thick substrate exhibits wideband performance and inclined radiation patterns. The measured results are in good agreement with the simulated ones in terms of bandwidth (more than 15% impedance bandwidth at 7.1GHz) and radiation pattern

Sofiene Bouaziz; Ahmed Ali; Sami Hebib; Herve Aubert

2010-01-01

488

Wide-band matched LNA design using transistor's intrinsic gate-drain capacitor  

Microsoft Academic Search

This paper presents the development of a wide-band amplifier with matched input impedance and low noise temperature over 10-20 GHz. Here, the novel wide-band feedback mechanism provided by the transistor's intrinsic gate-drain capacitor will be analyzed in detail with both the derived input reflection coefficient and noise temperature of the resulting circuit confirmed by their simulated counterparts. It is thus

Robert Hu

2006-01-01

489

A novel design method for wideband power amplifiers  

NASA Astrophysics Data System (ADS)

A new technique that permits the design of wideband high power amplifier stages (SSPAs) has been developed. The method is based on load pull power contours measured at the output of the device and large signal impedance matching at the input, both provided through measurements performed by an automatic computer controlled tuner system. Linear circuit analysis and optimization algorithms have been implemented in a software program that allows the design of the matching circuitry for power levels up to saturation. Nonlinear modeling or nonlinear circuit simulations are not required. The design method has been applied to a 3.7 to 4.2 GHz and a 12 to 15 GHz SSPA's stages. Measured results match closely with the predicted performance.

Tsironis, Christos

1992-05-01

490

Texture measurements of metal sheets using wideband electromagnetic acoustic transducers  

NASA Astrophysics Data System (ADS)

The group velocity of the zero-order symmetric Lamb wave mode (S0) has been measured on metal sheet as a function of angle to the rolling direction. Generation and detection of the Lamb wave was achieved using wideband non-contact ultrasonic electromagnetic acoustic transducers (EMATs). The EMATs were relatively small in size and employed permanent NdFeB magnets. The angular dependent velocity of the S0 mode was measured on both aluminium and stainless steel (316) sheet. The entire system was computer controlled and the data were processed as acquired. The generation EMAT was driven with a current pulse of 270 A (peak value). This high current level gave rise to a more powerful generation source than is usually obtained with EMATs, enabling measurements to be made on stainless steel sheet which is much less efficient for EMAT generation of S0 mode Lamb waves than aluminium sheet.

Dixon, S.; Edwards, C.; Palmer, S. B.

2002-04-01

491

Wideband Waveform Design principles for Solid-state Weather Radars  

SciTech Connect

The use of solid-state transmitter is becoming a key part of the strategy to realize a network of low cost electronically steered radars. However, solid-state transmitters have low peak powers and this necessitates the use of pulse compression waveforms. In this paper a frequency diversity wideband waveforms design is proposed to mitigate low sensitivity of solid-state transmitters. In addition, the waveforms mitigate the range eclipsing problem associated with long pulse compression. An analysis of the performance of pulse compression using mismatched compression filters designed to minimize side lobe levels is presented. The impact of range side lobe level on the retrieval of Doppler moments are presented. Realistic simulations are performed based on CSU-CHILL radar data and Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) Integrated Project I (IP1) radar data.

Bharadwaj, Nitin; Chandrasekar, V.

2012-01-01

492

Auroral spectral estimation with wide-band color mosaic CCDs  

NASA Astrophysics Data System (ADS)

Color mosaic CCDs use a matrix of different wide-band micro-filters in order to produce images with several (often three) color channels. These devices are increasingly employed in auroral studies to provide time sequences of two dimensional luminosity maps, but the color information is typically only used for qualitative analysis. In this study we use Backus-Gilbert linear inversion techniques to obtain quantitative measures of effective spectral resolution for multi-channel color mosaic CCDs. These techniques also allow us to explore the possibility of further improvements by modifying or combining multiple detectors. We consider two spectrally calibrated commercial color CCDs (Sony ICX285AQ and ICX429AKL) in order to determine effective wavelength resolution of each device individually, together, and with additional filters. From these results we develop methods to enhance the utility of existing data sets, and propose ways to improve the next generation of low-cost color auroral imaging systems.

Jackel, B. J.; Unick, C.; Syrjäsuo, M. T.; Partamies, N.; Wild, J. A.; Woodfield, E. E.; McWhirter, I.; Kendall, E.; Spanswick, E.

2013-12-01

493

A GPU-Based Wide-Band Radio Spectrometer  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

494

Miniature biotelemeter giving 10 channels of wideband biomedical data.  

NASA Technical Reports Server (NTRS)

A miniature biotelemeter has been developed for sensing and transmitting multiple channels of wideband biomedical data over a radio link. Its small size and weight make it capable of being carried by free-moving laboratory animals as small as rats. Ten data channels each of 5-kHz data bandwidth are provided to permit monitoring of a wide variety of physiological signals. Multichannel telemetry of electroencephalograms, electrocardiograms, electromyograms, state functions, and dynamic processes such as blood flow and body chemistry are possible applications. Utilization of newly available monolithic chip components, low-power COS/MOS MSI digital logic, and state-of-the-art hybrid mounting techniques makes this novel device useful for both research and clinical bioinstrumentation.

Carraway, J.

1972-01-01

495

5 Ultra Cold Neutrons  

Microsoft Academic Search

At the Paul Scherrer Institut (PSI) a new source of ultra cold neutrons (UCN) will be con- structed with the goal to improve the sensitivity to the neutron electric dipole moment (nEDM), which is sensitive to possible contributions from new physics. In addition the neu- tron decay parameters such as its life time may be studied more accurately. Presently, we

P. Fierlinger; S. Heule; U. Straumann

496

Cutting Edge RFID Technologies for NASA Applications  

NASA Technical Reports Server (NTRS)

This viewgraph document reviews the use of Radio-frequency identification (RFID) for NASA applications. Some of the uses reviewed are: inventory management in space; potential RFID uses in a remote human outpost; Ultra-Wideband RFID for tracking; Passive, wireless sensors in NASA applications such as Micrometeoroid impact detection and Sensor measurements in environmental facilities; E-textiles for wireless and RFID.

Fink, Patrick W.

2007-01-01

497

Optical impairments mitigation in millimeter-wave fiber-wireless systems  

NASA Astrophysics Data System (ADS)

Hybrid fiber-wireless networks for fixed wireless access operating in the millimeter-wave wave (mm-wave) frequency region have been actively pursued to provide untethered connectivity to ultra-high bandwidth communications. The architecture of such radio networks requires a large number of antenna base stations with high throughput to be deployed to maximize the geographical coverage with main switching and routing functionalities located in a centralized location. The transportation of mm-wave wireless signals within the hybrid network is subject to low opto-electronic conversion efficiency, fiber chromatic dispersion and also signal degradation due to nonlinearity along the link. One of the major technical challenges in implementing such networks lies in the mitigation of the various optical impairments that the wireless signals experience within the hybrid network. In this paper, we present an overview of the different techniques and schemes to overcome some of the signal impairments in transporting mm-wave radio signals over optical networks.

Lim, Christina; Nirmalathas, Ampalavanapillai; Novak, Dalma; Waterhouse, Rod

2008-11-01

498

Using pulse width modulation for wireless transmission of neural signals in multichannel neural recording systems.  

PubMed

We have used a well-known technique in wireless communication, pulse width modulation (PWM) of time division multiplexed (TDM) signals, within the architecture of a novel wireless integrated neural recording (WINeR) system. We have evaluated the performance of the PWM-based architecture and indicated its accuracy and potential sources of error through detailed theoretical analysis, simulations, and measurements on a setup consisting of a 15-channel WINeR prototype as the transmitter and two types of receivers; an Agilent 89600 vector signal analyzer and a custom wideband receiver, with 36 and 75 MHz of maximum bandwidth, respectively. Furthermore, we present simulation results from a realistic MATLAB-Simulink model of the entire WINeR system to observe the system behavior in response to changes in various parameters. We have concluded that the 15-ch WINeR prototype, which is fabricated in a 0.5- mum standard CMOS process and consumes 4.5 mW from +/-1.5 V supplies, can acquire and wirelessly transmit up to 320 k-samples/s to a 75-MHz receiver with 8.4 bits of resolution, which is equivalent to a wireless data rate of approximately 2.56 Mb/s. PMID:19497823

Yin, Ming; Ghovanloo, Maysam

2009-08-01