Ultra-wideband Range Research Articles

Wireless Signaling of Beta Detection Using Microdischarges

This paper explores the possibility of using microdischarges to generate broadband radio-frequency (RF) signaling from gas-based microdetectors of beta radiation. The concept is evaluated using two types of lithographically manufactured test structures: 1) a silicon/glass stack with etched detection cavities and 2) a planar metal-on-glass structure. The test structures include electrodes that bias a fill-gas region with a high electric field, in which incident beta particles initiate avalanche-driven microdischarge pulses that inherently transmit RF spectra with frequency content extending into the ultrawideband (UWB) range of communication. The discharge gaps range from 165 to 500 μm. The impact of operating pressure, fill gases (which are typically a mixture of Ne and N2), and electrode materials (Ni and Cu) on operating voltage and wireless signaling performance is evaluated. Tests are performed in the proximity of weak (0.1-1.0-μCi) beta sources (90Sr and 204TI). Both types of test structures are capable of producing UWB signals spanning > 1 GHz. Measurements in an anechoic chamber using various receiver antennas show that microdischarges can produce field strengths up to 90 dB · μV/m measured at 1.67 m from the test structure.

A Compact Parallel-Plane Perpendicular-Current Feed for a Modified Equiangular Spiral Antenna

The design and measurement is described of a compact (59.94 mm × 59.94 mm × 1.14 mm) bidirectional ultrawideband modified equiangular spiral antenna with an integrated feed internally matched to a 50-Ohm microstrip transmission line. An ultrawideband transition from microstrip to parallel-strip line soldered to a short (1.14 mm) twin-line transmission line feeds the spiral. The currents on the feed travel in a direction approximately perpendicular to the direction of the currents on the spiral at the points where the feed passes the spiral in close proximity (0.57 mm). Holes were etched from the metal arms of the spiral to reduce the impedance mismatch caused by coupling between the transmission line feed and the spiral. Measured and simulated radiation patterns and VSWR plots show good performance over the ultrawideband range (3.1-10.6 GHz) with a 2:1 VSWR everywhere in this range except for 3.33-3.95 GHz, which has a 3:1 VSWR. This spiral exhibits an elliptical polarization over the ultrawideband range.

Multiresolution Channel-Select Filter With Ultrawide Frequency Coverage

A multiresolution channel select filter topology is proposed for implementing a digitally-tunable bandpass response with ultra-wideband tuning range. This filter is composed of a chain of bimodal filter stages with self-complementary periodic frequency response. The frequency response behavior of this filter, the effect of parasitics, and the nonlinearities are studied in detail. A four-stage implementation is presented which is based on p-i-n diode switches and covers dc-2.5 GHz in 16 equal bandwidth channels with a maximum insertion loss of 6.7 dB.

Low-loss ultra-wideband double-sided parallel-strip line transition and power divider

A low-loss transition from a coaxial transmission line to a double-sided parallel-strip line is presented, and a 0° power divider is demonstrated using this transition. Simulated results from CST Microwave Studio and measured results show good agreement and good performance over the ultra-wideband range (3.1–10.6 GHz).

Hybrid Wideband Microstrip Wilkinson Power Divider Based on Lowpass Filter Optimized Using Particle Swarm Method

In this paper, an optimized microstrip hybrid 3-stage Wilkinson power divider based on lowpass filter is presented. The particle swarm optimization (PSO) method and method of moment (MoM) have been used to broaden the bandwidth to effectively cover 2–8 GHz ultra wideband range which is equal to 120% fractional bandwidth and to reject higher frequencies. The dimensions of filtering blocks and also Wilkinson isolating resistors are all used as optimization variables. The fitness function is evaluated by MOM simulations, and the MoM is used to calculate the response of the proposed Wilkinson power divider. A prototype hybrid power divider based on lowpass filter is then fabricated and measured to provide an experimental verification on the predicted features. Finally, both the method of moment and finite elements method are used to simulate the s-parameters. Simulation results on insertion loss and isolation of the implemented power divider are compared with measured values, and results for return loss is obtained using MoM and finite elements method.

무선 주파수 전력 측정을 위한 광대역 전력 센서 개발

본 논문에서는 300~3800MHz 주파수 대역에서 150mW~150W의 평균전력과 피크 전력을 검출할 수 있는 무선전력 검출센서의 개발에 대하여 기술하고 있다. 제안된 무선전력 센서는 기본적으로 전력의 크기를 검출하는 기능 외에 입력 신호의 주파수를 알아낼 수 있는 기능과 VSWR 측정 기능을 가지고 있다. 본 논문의 검출 센서는 듀얼 방향성 결합기의 설계, 입력 전력을 검출하여 DC 데이터로 분석할 수 있는 전력 검출부의 설계, 정확한 캘리브레이션 데이터 추출 방법 등의 세부 과정을 통하여 개발이 완성된다. 개발된 듀얼 방향성 결합기는 300~3800MHz 대역에서 0.085dB의 삽입손실과 3.8GHz에서 최소 30dB의 directivity 성능을 가지고 있다. 개발된 무선전력 센서는 주파수 결정능력과 함께 순방향 입력전력의 크기를 0.25dB 이내의 오차로 분석할 수 있고, 300~3800MHz의 주파수에서 150W의 고출력 동작에서도 1.17~1.96의 VSWR을 측정할 수 있는 성능을 지닌다. This paper describes the development of a power sensor for wireless signal over the ultra wideband range of 300~3800MHz with the detecting range of 150mW~150W. The proposed power sensor fundamentally has the function of not only detecting wireless power, but recognizing frequency and measuring VSWR. The development of the power sensor is completed through the design of dual directional coupler, design of power detector block which produces DC data using the corresponding RF input power level, and establishment of collecting the exact calibration data. The dual directional coupler has the operating frequency of 300~3800MHz with the 0.085dB of insertion loss, and directivity of 30dB at least at 3800MHz. The developed power sensor has the capability of power sensing with less than 0.25dB of resolution as well as measuring VSWR of 1.17~1.96 under the practical operating situation of very high power up to 150W at 300~3800MHz.

Integrated CMOS impulse UWB receiver front‐end design

AbstractA single‐chip broadband CMOS receiver front‐end, integrating a low‐noise amplifier (LNA), a correlator, and a template pulse generator, was investigated in nonsinusoidal time‐domain environment for possible use as an impulse‐type ultra‐wideband (UWB) receiver front‐end. Particularly, the CMOS LNA and the multiplier making up the core component of the correlator were designed, fabricated, and tested to verify operation in the UWB range. Time‐domain results of the integrated CMOS receiver front‐end demonstrate its workability as a receiver for nonsinusoidal UWB applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2590–2595, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24682

Design and analysis of an ultrawideband three‐section microstrip‐slot coupler

AbstractThis article presents the design of a three‐section microstrip‐slot coupler aimed for operation in the frequency band between 3.1 and 10.6 GHz. The coupler's design is accomplished in a two‐layer dielectric substrate and consists of rectangular sections of microstrip lines that are broadside coupled by a slot in the common ground plane supporting the two substrates. The initial dimensions are worked out using simple formulas. Next, CST Microwave Studio simulator is applied to carry out the final design. The designed coupler is manufactured and its performance is tested. The tests show a good performance over an ultra wide frequency band range from 3.1 to 10.6 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1889–1892, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24484

Ultra-wideband power dividers with good isolation and improved sharp roll-off skirt

A novel class of ultra-wideband power dividers with good isolation and sharp roll-off skirt is proposed, analysed and designed on microstrip topology. By introducing a pair of quarter-wavelength short-circuited stubs and/or parallel coupled lines to two symmetrical output ports, good performance in terms of equal power splitting is achieved over the ultra-wideband range, that is 3.1-10.6-GHz. A single resistor is then placed between two output ports such that good isolation is achieved between them. By virtue of direct-current chocked and half-wavelength transmission zeros of short-circuited stubs and coupled lines, out-of-band roll-off skirt near the cut-off frequencies is sharpened to a great extent. Two types of these power dividers are analysed and optimised using the simple transmission-line based even- and odd-mode approach. Based on comparative study of these two types, an ultra-wide band divider with coupled lines has been designed and fabricated. Measured results evidently confirm the predicted features of the divider in terms of return losses at all the three ports, input-to-output insertion losses and output-to-output isolation.

IMPROVEMENTS IN A HIGH GAIN UWB ANTENNA WITH CORRUGATED EDGES

In this paper, a novel corrugated structure at the edges of the Vivaldi substrate is presented. Compared with the Vivaldi antenna without corrugated structure, the new structure has a better radiation pattern. While compared with the traditional corrugated structure, the new structure has a better front-to-back ratio (F/B ratio). Properly chosen thickness and dielectric constant of substrate ensure a relatively small size while the lower frequency is around 1GHz. A Vivaldi structure also promises high gain in ultra-wideband (UWB) range. For its planar structure, the antenna is easily fabricated with a low cost. The design of a novel Vivaldi antenna described in this paper operates from 1GHz to more than 3GHz with i10dB return loss and produce the gain with a range of 7dBi » 11dBi. The current design is one of the most ideal antennas to be used for through-wall radar.

Metamaterial-Based Phase Shifters for Ultra Wide-Band Applications

In this paper, the idea of using two composite right/left handed (CRLH) transmission lines (TLs) in design of microstrip phase shifter is suggested for the first time and optimized by Genetic Algorithm for achieving the desired magnitude and phase characteristics over ultra wide-band range of microwave frequencies. In this paper, a 90° phase shifter is developed in an extra wide bandwidth from 3 GHz to 10 GHz, with only ±5° phase error. The proposed phase shifter is useful for UWB applications which can be implemented by both the lumped-elements and microstrip CRLH TLs.

Two new space-time codes for UWB range extension

Ultrawideband (UWB) radio is a promising solution for low and high data rate wireless communications over short ranges. Space-time (ST) coding techniques are known to be simple and practical ways to increase both the spectral efficiency and the capacity in wireless communications. So far, few contributions have looked over multiple-inputs multiple-outputs (MIMO) UWB systems. In this paper we introduce two new families of ST codes suitable for binary pulse modulated (BPM) and pulse position modulated (PPM) UWB systems. The codes are characterised by full-rate, full-diversity and low complexity at the receiver side. The probability of error resulting from the use of these space-time codes in a typical MIMO UWB channel is analytically derived. Simulations support analysis for various numbers of transmit and receive antennas in order to show that the two methods can effectively enlarge the transmission range of UWB devices.

An approach to remove the clutter and detect the target for ultra-wideband through-wall imaging

Through-wall imaging (TWI) is important from the point of view of rescue operations and surveillance. Several researchers have been working in this field but have still not obtained any concrete results. TWI using narrow band radar faces the problem of low resolution whereas ultra-wideband (UWB) radar provides better resolution, classification and low loss for the imaging signals. TWI faces many challenges in collecting the scattered electromagnetic fields from objects located behind the wall and also in processing the data in order to detect, locate and image the object. One of the important factors for achieving a high-quality image is to use clutter reduction techniques so that clutter as well as false target detection can be minimized. Therefore, in this paper, an attempt has been made to develop a clutter reduction technique for TWI in the UWB range for target detection. For this purpose, an experiment has been carried out with a TWI system in the UWB range for determination of the target position and size along with the development of the signal processing technique to minimize the clutter. A singular value decomposition (SVD) algorithm has been applied for clutter reduction. Encouraging results have been obtained from a metallic target behind a plywood wall of thickness 12 mm and a brick wall of thickness 110 mm. Application of the SVD approach provides a powerful technique for minimizing clutter and false detection for the TWI system in the UWB range. The position of the target behind the wall is predicted quite accurately by taking into account the propagation speed of waves through-walls. The approximate size of the target is also predicted successfully.

Ultra-Wideband Power Divider With Good In-Band Splitting and Isolation Performances

An ultra-wideband (UWB) power divider on microstrip line is proposed, analyzed and designed. This divider is formed by installing a pair of stepped-impedance open-circuited stubs and parallel-coupled lines to two symmetrical output ports. In addition, a single resistor is properly placed between two output ports. After simple transmission line theory analysis, it is demonstrated that 3 dB power splitting from one input to two output ports, good impedance matching at all the three ports and excellent isolation between two output ports are achieved over the specified 3.1-10.6 GHz UWB range. Finally, a prototype divider is fabricated and measured to provide an experimental verification on the predicted attractive features.

All-fiber incoherent frequency-to-time mapping method for microwave signal generation with baseband transmission and multicasting support

We present a proof-of-principle experiment for achieving simultaneous distribution of baseband radio-frequency data and up-conversion with broadcasting support over a passive optical network. The technique is based on an incoherent frequency-to-time mapping method for pulse shaping. Specifically, we synthesize the spectral density function of sliced ASE noise from an EDFA with a periodic Mach–Zehnder fiber interferometer optical filter. By using external intensity modulation combined with propagation in an optical fiber, after photodetection, the resultant averaged temporal pulse profile resembles the shape of the incoherent source. The photodetected signal contains both the baseband data and an up-frequency converted copy with central wavelength for the microwave carrier into the ultra-wideband range and tuning capability by selection of the fiber length.

A NOVEL ULTRA-COMPACT BROADBAND ANTENNA FOR MICROWAVE BREAST TUMOR DETECTION

This paper presents a novel resistively loaded antenna design for microwave breast cancer detection. The antenna is planar and ultra-compact,and can be easily manufactured using PCB technology with embedded thin-film resistive layers. Through numerical simulations,the antenna demonstrates a return loss below −10 dB over a wide frequency range from 2 to 35 GHz. For pulse radiation in the ultra-wideband (UWB) range in a biological medium, the antenna shows an excellent fidelity above 0.95 and a relatively high radiation efficiency of 39.21% in comparison to resistively loaded antennas. In addition,a design rule guideline is presented for designing the antenna to radiate in a specific background medium and with a given lower operating frequency. Finally,a complete microstrip feed design is presented for the antenna operating in the UWB range.

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

A compact ultra-wideband (UWB) bandpass filter (BPF) with narrow notched (rejection) band in the UWB passband realized on a microstrip line is implemented and presented in this letter for use in wireless communication applications within the unlicensed UWB range set by the Federal Communications Commission (FCC). The filter consists of five short-circuited stubs separated by nonredundant connecting lines in order to exhibit a high selectivity filtering characteristic. The narrow notched (rejection) band was introduced by using a new technique which involves embedding open stubs in the first and last connecting lines in order to reject any undesired existing radio signal which may interfere with the determined UWB passband. The bandwidth of the notched filter can be controlled by adjusting the width of the stubs or the gaps or both. The length of the stubs can be tuned to select a specific frequency for the notched band. The embedded stubs can be used to excite single or double band-reject response. Two UWB BPFs with narrow notched band having a fractional bandwidth (FBW) of about 4.6% and 6.5% were realized theoretically and verified by full-wave EM simulation and the experiment. Excellent agreement between the predicted and measured results was obtained and is demonstrated

Low-power-consumption and high-gain CMOS distributed amplifiers using cascade of inductively coupled common-source gain cells for UWB systems

A distributed amplifier with new cascade inductively coupled common-source gain-cell configuration is presented. Compared with other existing gain-cell configurations, the proposed cascade common-source gain cell can provide much higher transconductance and, hence, gain. The new distributed amplifier using the proposed gain-cell configuration, fabricated via a TSMC 0.18-mum CMOS process, achieves an average power gain of around 10 dB, input match of less than -20 dB, and noise figure of 3.3-6.1 dB with a power consumption of only 19.6 mW over the entire ultra-wideband (UWB) band of 3.1-10.6 GHz. This is the lowest power consumption ever reported for fabricated CMOS distributed amplifiers operating over the whole UWB band. In the high-gain operating mode that consumes 100 mW, the new CMOS distributed amplifier provides an unprecedented power gain of 16 dB with 3.2-6-dB noise figure over the UWB range

Conformal Double Exponentially Tapered Slot Antenna (DETSA) on LCP for UWB Applications

We discuss the use of a double exponentially tapered slot antenna (DETSA) fabricated on flexible liquid crystal polymer (LCP) as a candidate for ultrawideband (UWB) communications systems. The features of the antenna and the effect of the antenna on a transmitted pulse are investigated. Return loss and E and H plane radiation pattern measurements are presented in several frequencies covering the whole ultra wide band. The return loss remains below -10 dB and the shape of the radiation pattern remains fairly constant in the whole UWB range (3.1 to 10.6 GHz). The main lobe characteristic of the radiation pattern remains stable even when the antenna is significantly conformed. The major effect of the conformation is an increase in the cross polarization component amplitude. The system: transmitter DETSA-channel receiver DETSA is measured in frequency domain and shows that the antenna adds very little distortion on a transmitted pulse. The distortion remains small even when both transmitter and receiver antennas are folded, although it increases slightly.

On the Parametrization of the Three-Dimensional Rotation Group

Parameterization of group of rotations of Euclidean three-dimensional space applied to integration of rigid body motion equations