bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel high‐order time‐domain scheme for three‐dimensional Maxwell's equations
Authors: Huang Zhi‐Xiang , Sha Wei , Wu Xian‐Liang , Chen Ming‐Sheng
Published: April 2006

A novel high‐order time‐domain scheme with a four‐stage optimized symplectic integrator propagator is presented for 3D electromagnetic scattering problems. The scheme is nondissipative and does not require more storage than the classical finite‐difference time‐domain (FDTD) method. The numerical results show the scheme has better stability and more efficiency than the classical FDTD method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1123–1125, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21563
Analog characteristics of electroabsorption modulator for RF/optic conversion; RF gain and IMD3
Authors: Chung Yong‐Duck , Kang Young‐Shik , Choi Kwang‐Seong , Kim Sung‐Bock , Kim Jeha
Published: April 2006

We design and fabricate a traveling‐wave electroabsorption modulator for RF/optic conversion. The RF gain is measured with a simple RF/optic link. It is related to the optical transfer curve. The input optical power causes the change of the transfer curve so that the RF gain varies accordingly. The RF/optic conversion gain shows a close relationship with the slope efficiency of transfer curve. Linearity is also one of the important characteristics for analog applications. We evaluate the linearity of the module from the 3rd‐order intermodulation distortion (IMD3). © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1151–1155, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21564
Electromagnetic scattering from cylinder described by high‐order inhomogeneous impedance boundary conditions
Authors: Tezel Necmi Serkan , Paker Selçuk
Published: April 2006

In this study, the electromagnetic scattering from a high‐order inhomogeneous impedance cylinder is investigated. The method presented in this paper is based on the series representation of incident and scattering fields. The inhomogeneous‐surface impedance functions are also expressed by terms of Fourier series. By using the boundary condition on the surface of the cylinder, a series equation is obtained. This equation is reduced the matrix equation by using the orthogonal properties of the Fourier expansion functions and unknown mode coefficients can be calculated. The obtained results are compared with those obtained using the method of moments (MoM) for 1st‐order inhomogeneous‐surface impedance cylinder and good agreements are observed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1148–1151, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21565
Compensation of intermodulation distortion of laser diode by using optoelectronically predistorted signals
Authors: Choi In‐Hyuk , Lee Sang‐Hoon , Kwon Hyuk‐Choon , Choi Young‐Wan , Han Sang‐Kook
Published: April 2006

We have experimentally demonstrated the predistortion scheme for linearization of a laser diode which transmits 1.2‐ and 1.25‐GHz RF signal over single‐mode fiber. The suppression of intermodulation distortion was achieved by using an additional laser diode to realize the predistorted signals. We have shown a 22.5‐dB reduction of the 3rd‐order intermodulation distortion and an 11‐dB improvement in the spurious‐free dynamic range. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1144–1148, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21566
Nonhomogeneous current injection for the enhancement of semiconductor optical amplifier‐based wavelength converters
Authors: Gallep Cristiano M. , Cavalcanti André L. R. , Ribeiro Napoleão , Conforti E.
Published: April 2006

Experimental data and calibrated simulations for an enhanced wavelength converter based on semiconductor optical amplifiers cross‐gain modulation are presented. Theoretical results for spectral components along the SOA cavity are discussed and a nonhomogeneous bias current injection profile is suggested with an improvement of 4 dB in the XGM wavelength converted eye‐opening. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1141–1144, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21567
Coherence‐time characterization in a suburban environment
Authors: Ribeiro Antonio Marcelo O. , Conforti Evandro
Published: April 2006

An experimental technique for the coherence‐time characterization of a mobile radio envelope employing the autocorrelation coefficient is presented. Field trials at 836 MHz in a suburban area are carried out using a spectrum analyzer as the acquisition apparatus. Autocorrelation coefficients are calculated from the acquired envelopes and the coherence time is calculated for a 0.5 correlation level. Due to the significant variation of the coherence time with the position of the mobile receiver, cumulative distribution functions of the coherence time are calculated in order to interpret the results. The coherence‐time parameter is estimated from these cumulative distribution functions by computing the value above which the coherence time stays for 90% of time. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1137–1141, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21568
A directivity‐diversity microstrip antenna array in millimeter wave
Authors: Caillet M. , Lafond O. , Himdi M. , Le Garrec L.
Published: April 2006

The purpose of this paper is to report on a microstrip reconfigurable antenna in the millimeter‐wave range. This antenna has directivity diversity and is based on a four‐element array. An original method is outlined to guarantee matching for each configuration without changing circuit. Great results have been achieved with a passive prototype and an active antenna is under consideration. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1190–1194, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21569
Detection of dielectric contrast of breast tissues using confocal microwave technique
Authors: Bindu G. , Abraham Santhosh John , Lonappan Anil , Thomas Vinu , Aanandan C. K. , Mathew K. T.
Published: April 2006

Confocal microwave technology is explored as a screening tool to detect regions of dielectric contrast in breast tissues. When exposed to microwaves, malignant breast tissues exhibit electrical properties that are significantly different from that of healthy breast tissues, due to the variations of bound water content. In vitro studies of normal breast tissues having cancerous inclusions in the presence of a matching coupling medium are reported here. Experimentally obtained time‐domain results are substantiated by finite‐difference time‐domain analysis. It is observed that the dielectric contrast of breast tissues is satisfactorily determined using the pulsed confocal microwave technique. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1187–1190, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21570
Iterative‐solvers for numerical analysis of photonic devices
Authors: Claudio Kleucio , Rodriguez‐Esquerre V. F. , da Silva J. P. , Hernández M. F. G. , Hernández‐Figueroa H. E.
Published: April 2006

An assessment of four linear‐system iterative solvers is carried out through the simulation of a key 2D photonic crystal structure. Among these solvers, the biconjugate gradient stabilized (BCGS) in conjunction with the incomplete LU (ILU) decomposition, shows the best performance and can be regarded as a promising candidate for large‐scale computation. In addition, the iterative solver with the best performance is applied to analysis of the directional optical coupler and transverse anisotropic waveguide. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1182–1186, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21571
Selective re‐meshing: A new approach to include mode stirring effects in the steady state FDTD simulation of microwave heating cavities
Authors: George Jacob , Bergman Richard
Published: April 2006

A new selective remeshing approach to efficiently utilize the finite‐difference time‐domain (FDTD) method for simulating 3D microwave heating cavities with rotating mode stirrers is presented here. The proposed scheme is implemented in a ∼300L multimode applicator and the result compares favorably with a validation experiment. The proposed implementation of the selective remeshing scheme is efficient, in that the remeshing is done “on the fly” and the previous FDTD solution is used to continue the simulation as a single run of the FDTD solver. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1179–1182, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21572
Doppler‐invariant property of hyperbolic frequency modulated waveforms
Authors: Yang J. , Sarkar T. K.
Published: April 2006

When a target has a large velocity, the Doppler effect is not negligible. In that case, pulse compression by means of a linear frequency modulation suffers from significant signal loss in performance due to the mismatch between the reflected signal and the matched filter caused by the Doppler distortion. This problem can be avoided by using a hyperbolic frequency‐modulated waveform, which has the inherent Doppler‐invariant property. In this paper, we demonstrate that the hyperbolic frequency‐modulated waveform is Doppler‐invariant under the assumption that the target velocity is constant, while for a linear frequency‐modulated waveform it is not. Two numerical examples with rectangular and Gaussian pulse envelopes are presented to compare the performance of these two different modulation schemes under several different levels of Doppler distortions. We also compare the performance of this method with another Doppler‐invariant pulse compressor based on the bipolar waveform and multiple integrator pair. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1174–1179, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21573
Small dual‐frequency shorted patch antenna
Authors: Kan H. K. , Pavlickovski D. , Waterhouse R. B. , Rowe W. S. T.
Published: April 2006

In this paper we present a small dual‐frequency printed antenna based on a square shorted‐patch configuration with an embedded slot to generate the second resonant frequency. The antenna resonance is at 1.58 and 2.6 GHz with 10‐dB return‐loss bandwidths of 1.3% and 3.3% for the lower and higher resonances, respectively. The overall dimensions of the antenna are 0.105λ0 × 0.105λ0 × 0.05λ0 and it is simple to construct. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1225–1227, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21574
A multilevel gain all‐optical gain‐controlled EDFA with suppressed relaxation oscillations
Authors: de Oliveira Júlio C. R. F , Rosolem João B. , Bordonall Aldário C.
Published: April 2006

The characterization of an all‐optical gain‐controlled erbium‐doped fiber amplifier using an embedded variable optical attenuator in the feedback loop is presented. The gain is controlled by the attenuation level with high equalization. The amplifier presents low noise figure and strongly suppressed relaxation oscillations during channel add and drop. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1222–1225, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21575
Design and performance evaluation of a 156‐Mb/s point‐to‐multipoint millimeter‐wave fiber‐radio access link
Authors: Choi Sung Tae , Yang Ki Seok , Nishi Seiji , Shimizu Satoru , Tokuda Kiyohito , Kim Yong Hoon
Published: April 2006

A 60‐GHz point‐to‐multipoint (P‐MP) fiber‐radio access link with data rate of 156 Mb/s is presented. For a compact system configuration, a small‐size 60‐GHz transceiver module with planar antennas is developed. A point‐to‐point (P‐P) full‐duplex fiber‐optic configuration is extended to the scheme with multiple access points (APs) by using a tree coupler and a dense wavelength‐division multiplexing (DWDM) multiplexer (MUX). The bit error rate (BER) performances of the 60‐GHz fiber‐radio access link are measured and compared. Furthermore, the effect of the extension to the scheme with multiple APs is evaluated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1219–1222, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21576
GTD model‐based target identification for ultra‐wideband radar using matching pursuits and a likelihood‐ratio test in the frequency domain
Authors: Wang Dang‐Wei , Ma Xin‐Yi , Su Yi
Published: April 2006

The E‐pulse technique has been applied in the past to the early‐time component of an ultra‐wideband radar response. Though its availability has been validated by several scale‐model targets, as pointed out by Poter's research results, the Prony model used in the E‐pulse technique is mismatched with the true target‐scattering behavior. In this paper, according to Poter's GTD model, the type and location parameters of scattering centers are used as templates to identify targets. With parameter templates, a GTD model‐based approach to target identification for ultra‐wideband radar using matching pursuits and likelihood‐ratio test (for short MPLRT‐GTD) is developed. The simulation results using measured scattering signatures of two targets in an ultra‐wideband chamber are provided to contrast the performance of the MPLRT‐GTD to the LRT and Li's E‐pulse technique. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1215–1218, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21577
An experimental investigation of buried‐object imaging in a homogeneous medium using synthetic‐aperture radar concepts
Authors: Ozdemir Caner , Ling Hao
Published: April 2006

An experimental investigation is conducted to image buried objects. A Fourier‐based imaging algorithm based on synthetic‐aperture radar (SAR) concepts is applied to the scattered data from buried dielectric targets in a homogeneous medium. An experimental setup is constructed to apply the algorithm. Three‐dimensional images of water bottles and plastic targets buried in sand are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1209–1214, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21578
Novel microstrip backward coupler with metamaterial cells for fully planar fabrication techniques
Authors: Jarauta E. , Laso M. A. G. , Lopetegi T. , Falcone F. , Beruete M. , Baena J. D. , Marcotegui A. , Bonache J. , García J. , Marqués R. , Martín F.
Published: April 2006

By using a recently proposed approach to synthesize 1D metamaterials in planar circuit technology, compatible with fully planar fabrication techniques, a novel backward coupler has been designed and fabricated. It has been implemented in microstrip technology by means of complementary split‐ring resonators (CSRRs), etched in the ground plane, and series capacitive gaps. This way, we obtain the necessary left‐handed properties for reversing the forward coupling (typical of co‐directional coupled‐line couplers) into backward coupling. The simulation as well as measurement results confirm the enhanced properties of the proposed couplers. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1205–1209, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21579
New wide‐aperture‐dimension formula obtained by using a particle swarm optimization for optimum gain pyramidal horns
Authors: Akdagli Ali , Guney Kerim
Published: April 2006

A new formula for the wide aperture dimension of a pyramidal horn is presented. It is obtained by using a particle‐swarm optimization (PSO) algorithm, and is used in successfully designing optimum‐gain pyramidal horns. The computed gains of the designed pyramidal horns are in very good agreement with the desired gains. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1201–1205, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21580
Frequency variable dual bands microstrip antenna design
Authors: Prakash Thakur Jay , Park Jun‐Seok
Published: April 2006

A new approach is proposed to design a frequency‐variable dual‐band microstrip antenna. Two unbalanced microstrip lines are used to feed microstrip patch vertically with a branch‐line coupler. The entire structure is designed on a single‐layer substrate. The resonant frequencies of the microstrip patch can be changed by varying the dimensions of the unbalance feed lines. A prototype of the proposed antenna is fabricated and measured. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 11991–1201, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21581
Radio over fibre systems using perfluorinated graded index polymer optical fibre
Authors: Lethien Christophe , Goffin André , Vilcot Jean‐Pierre , Loyez Christophe
Published: April 2006

The paper compares, in terms of the error vector magnitude (EVM), the transmission of two radiocellular standards (GSM and UMTS) on two different kinds of multimode fibre (glass optical fibre and polymer optical fibre). It has been so established that the perfluorinated graded index polymer optical fibre is able to carry on wireless signals through 300‐m length using standard COTS components specifically designed for glass fibre. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1197–1199, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21582
New method to design a low‐phase‐noise millimeter‐wave PLL frequency synthesizer
Authors: Ma Haihong , Tang Xiaohong , Wu Tao , Cao Zhou
Published: April 2006

Based on the theory of phase‐noise analysis and estimation, a new method to obtain low‐phase‐noise millimeter‐wave phase‐locked loop (PLL) frequency synthesizer is presented. In order to verify its feasibility, a W‐band PLL frequency synthesizer working at 95 GHz is designed. A low phase noise of −90.44 dBc/Hz at 10‐kHz offset is achieved, which is well coincident with the estimated value. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1194–1197, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21583
Design of a multiband VCO using a cascode FET mixer
Authors: Kim Jeongpyo , Yoo Hwasu , Choi Jaehoon
Published: April 2006

This paper presents the voltage‐controlled oscillator (VCO) with a cascade FET structure and self‐oscillatory property. The self‐oscillation (SO) frequency of the designed VCO is 1.45 GHz and the frequency is tuned from 1.06 to 1.42 GHz by using an added varactor diode. Mixing SO signals with the external signal of 500 MHz having a 0‐dBm power level, the VCO can generate various LO signals from 560 to 1920 MHz. The tuning range of the VCO is expanded from 29% to 109.7%. The implemented VCO operates at 3 V with 30‐mA current consumption. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1005–1007, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21584
Effect of shape of patterns on the performance of microstrip photonic band‐gap filters
Authors: Karbassian M. M. , Ghafouri‐Shiraz H.
Published: April 2006

In this paper, two different uniform photonic band‐gap (PBG) structures used as stopband filters for microstrip lines at 5.4 GHz are proposed and compared in terms of the pattern shapes' effect on the S‐parameters. This suggests the use of a 1D pattern to reduce the transversal size of the filters. The devices consist of 50Ω microstrip transmission line and periodical patterns including circles and squares etched on the ground plane of microstrip line. No drilling through the substrate is needed. The filters exhibit well‐defined stopband and are simulated by 3D full‐wave electromagnetic analysis using HFSS™. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1007–1011, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21585
A tunable photonic RF notch filter based on opto‐VLSI technology
Authors: Zheng Rong , Alameh Kamal E. , Wang Zhenglin
Published: April 2006

In this paper, we propose a novel tunable transversal photonic RF notch filter based on opto‐VLSI technology. By using an array of fiber Bragg gratings (FBGs) in conjunction with an opto‐VLSI processor, the broadband light source can be spectrally sliced and attenuated, hence realizing a two‐tap RF notch filter with stepwise true‐time delays and variable weights. In addition, the free spectral frequency and notch depth of the RF notch filter can be tuned by driving the opto‐VLSI processor with optimized phase‐only holograms. We experimentally demonstrate the proposed tunable RF notch filter structure and the results show that a notch depth greater than 40 dB can be attained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1011–1015, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21586
Digitally controlled programmable high‐speed variable optical attenuator
Authors: Li Sailu , Jin Xiaofeng , Zhang Xianmin , Zou Yingyin Kevin
Published: April 2006

A digital closed‐loop controlled variable optical attenuator (VOA) module using an FPGA (Field Programmable Gate Array) chip for optical‐power‐fluctuation suppression is demonstrated in this paper. A VOA based on transparent electro‐optical ceramic, OptoCeramic® PLZT, is used to provide high‐speed optical power control. With logarithm amplifiers and A‐D‐A feedback circuitry, this VOA module could be designed to operate as either an attenuator or a power controller. The module can be used to filter out the optical power fluctuation up to 300 kHz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1019–1021, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21588
Frequency‐selective surface composed of aperture‐coupled high‐impedance surfaces
Authors: Davies R. W. , Morrow I. L. , Cooper J. F. , Youngs I.
Published: April 2006

A compact new FSS structure which provides a narrow band‐pass response is reported. The structure is composed of two high‐impedance surfaces of tightly coupled dipole‐strip conductor arrays placed back‐to‐back with a common ground plane. Each element on one surface is coupled to its neighbour on the opposite surface, via a slot aperture etched in the ground plane. A design procedure is described for optimisation of the dipole and coupling‐slots dimensions in order to excite and mode match the appropriate transmission frequency. The computed results demonstrate the coupling mechanism and transmission performance. Free‐space measurements of the FSS confirm the narrowband transmission characteristics which are potentially useful for antenna and radome‐type applications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1022–1025, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21589
Gain‐flattened distributed Raman amplifier with 38‐nm bandwidth using dual‐pump wavelength
Authors: Mahdi Mohd Adzir , Sheih Shou‐Jong
Published: April 2006

In this paper, a 38‐nm wideband gain‐flattened distributed Raman amplifier utilising two pump wavelengths is experimentally demonstrated. The pump combination of 1430 and 1456 nm with 26‐nm spacing has enabled a gain flatness of less than 1.1 dB at a Raman on‐off gain of 10 dB. The flat gain is obtained through a careful pump‐power adjustment between these two pump wavelengths without any gain‐flattening filters. The 38‐nm bandwidth covers signal wavelengths from 1530.33 to 1568.78 nm. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1025–1028, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21590
ADI‐WEPML: Unconditionally stable PML algorithm for truncating WE‐FDTD domains
Authors: Ramadan Omar
Published: April 2006

Efficient and unconditionally stable perfectly matched layer (PML) formulations are presented for truncating the scalar wave‐equation finite‐difference time‐domain (WE‐FDTD) grids. The proposed formulations are based on incorporating the alternating‐direction‐implicit FDTD (ADI‐FDTD) scheme into the scalar wave‐equation derived in the PML region at the domain boundaries. A numerical example carried out in the 2D domain is included and it is observed that the time step of the proposed formulations is not bounded by the CFL stability limit of the conventional WE‐FDTD algorithm, but by the required accuracy level. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1029–1032, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21591
CPW‐fed triangular antenna with a frequency‐band notch function for ultra‐wideband application
Authors: Liu Wen‐Chung , Kao Ping‐Chi
Published: April 2006

A novel ultra‐wideband (UWB) design of a single‐layer coplanar waveguide (CPW)‐fed planar monopole antenna with a frequency‐band notch function is presented. By inserting an opened rectangular loop slot to the ground‐notched triangular patch and adjusting the dimensions of the slot, the proposed antenna, which includes two notched ground planes only 24 mm in width and 31 mm in height, can reach a frequency bandwidth, defined by VSWR < 2, of 9 GHz (from 3.1 to 12.1 GHz), covering the entire UWB band (3.1–10.6 GHz), and have a frequency notch of 780 MHz (from 5.06 to 5.84 GHz) for band rejection of the IEEE 802.11a frequency band (5.15–5.825 GHz). Good monopolelike radiation patterns and antenna gains, except in the notched frequency band, have also been obtained. Details of the proposed antenna design and the measured results are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1032–1035, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21592
Optimized phase noise of LC VCO using an asymmetric‐inductance tank in InGaP/GaAs HBT technology
Authors: Yoon Jae‐Ho , Lee Sang‐Hun , Koh Ah‐Rah , Kennedy Gary P. , Kim Nam‐Young
Published: April 2006

This paper describes fully integrated low‐phase‐noise MMIC voltage‐controlled oscillators (VCOs) for an adaptive‐feedback interference‐cancellation system (AF‐ICS). The asymmetric‐ and symmetric‐inductance tank structures were combined with VCOs to obtain VCOs with low‐phase‐noise performance. The asymmetric‐inductance tank VCO (AIT‐VCO) has a tuning range of 261 MHz with an output power of −11.53 dBm at 1.715 GHz. Furthermore, the phase noise of this VCO is −117.3 dBc/Hz and −129.3 dBc/Hz at 100‐kHz and 1‐MHz offset frequencies, respectively. The symmetric‐inductance tank VCO (SIT‐VCO) has a tuning range of 160 MHz with an output power of −15 dBm at 1.664 GHz. Furthermore, the phase noise of this VCO is −102.4 dBc/Hz and −121.9 dBc/Hz at 100‐kHz and 1‐MHz offset frequencies, respectively. Each of these VCOs occupies a total chip area of 0.9 × 0.9 mm2. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1035–1040, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21593
Impedance matching of a loaded microstrip transmission line using parasitic elements
Authors: Matzner H. , Ouzan S. , Moalem H. , Arie I.
Published: April 2006

Impedance matching of a loaded microstrip transmission line is performed by using only parasitic elements. By the term “parasitic” matching element we mean that there is no physical connection between the conductors of the matching subsystem and the conductors of the main circuit. We construct a so‐called λ/4 parasitic transformer by adding a dielectric brick above the microstrip line, and another conducting strip above the brick. It is shown that a very good matching performance is achieved with the λ/4 parasitic transformer. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1040–1042, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21594
Compact broadband rectangular microstrip antennas
Authors: Deshmukh Amit A. , Kumar Girish
Published: April 2006

Compact and broadband gap‐coupled microstrip antennas using modified variations of the rectangular microstrip antenna (MSA), namely, C‐shaped, shorted L‐shaped, W‐shaped, and square‐ring MSAs, are proposed. These antennas have large bandwidth with a reduced total patch size. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1043–1046, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21595
Modeling the I‐V characteristics of the power microwave FETs with the Angelov model using pulse measurements
Authors: Loo‐Yau J. R. , Reynoso‐Hernández J. A. , Zuñiga J. E. , Hirata‐Flores F. I. , Ascencio‐Ramírez Hugo
Published: April 2006

In this paper, a simple and effective method of extracting the values of the parameters of the Angelov nonlinear I(V) model of GaAs HJ‐FETs is presented. In the proposed method, the coefficients of the function ψ are determined from I(V) pulse measurements, using the least‐squares optimization method. The utility of the proposed method is demonstrated by modeling the I(V) characteristic of the different families of packaged medium‐power GaAs HJ‐FETs designed for mobile communications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1046–1050, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21596
Effective complex permittivity and permeability of composite planar left‐handed transmission‐line metamaterials on CPW
Authors: Gao Jing , Zhu Lei
Published: April 2006

We report the effective complex permittivity and permeability of 1D planar left‐handed transmission‐line metamaterials. These metamaterials are formed on coplanar waveguide (CPW) with simultaneous load of series‐capacitive and shunt‐inductive elements in periodic intervals. By employing our self‐calibrated method of moments (MoM), the effective permittivity and permeability of these 1D metamaterials are numerically derived to illustrate the propagating and evanescent guided‐wave behaviors over a microwave frequency range. We demonstrate that, in a certain frequency band, the permittivity and permeability simultaneously become negative with zero imaginary parts, and the transmission phase of a finite‐extent CPW metamaterial becomes negative, as exhibited by both simulation and measurement. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1050–1052, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21597
Dual‐frequency planar‐fed microstrip patch antenna
Authors: Elsdon M. , Qin Y.
Published: April 2006

A dual‐frequency patch antenna with an inset feed in presented and discussed. It is demonstrated that by cutting two slots into one of the radiating edges of a microstrip patch antenna, a dual‐frequency response with a frequency ratio from 1.03 to 2.0 can be achieved. It is also shown that this design is less sensitive to feed position, which allows the use of an inset planar feed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1053–1054, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21598
Analysis of scattering by composite conducting and dielectric bodies using the single integral equation method and multilevel fast multipole algorithm
Authors: Wang P. , Xia M. Y. , Zhou L. Z.
Published: April 2006

A single integral equation (SIE) method is developed to analyze the electromagnetic scattering from 3D composite conducting and dielectric bodies. Compared with the conventional coupled integral equation (CIE) method, the SIE method reduces the number of unknowns by a factor of two for dielectric surfaces and has faster convergence for an iterative solution. The multilevel fast multipole algorithm (MLFMA) is incorporated to reduce the computing complexity and memory requirement. The numerical results show that the proposed SIE‐MLFMA method is accurate and efficient. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1055–1059, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21599
Miniaturized elliptic bandpass filter using the novel coplanar double stepped impedance resonators
Authors: Jang Suk‐Hyung , Lee Jong‐Chul
Published: April 2006

This paper presents the design and experimental results of the new miniaturized elliptic coplanar bandpass filter (EC BPF) using two types of double stepped impedance resonators (DSIRs) operating at a center frequency of 1.38 GHz. Miniaturization in the proposed BPF is achieved by connecting the transmission line between the middle of two SIRs contained in a single DSIR and both grounded planes. In addition, bond‐wire bridges connected between both grounded planes (which are needed in various coplanar waveguide structures) are not required. The new four‐pole EC‐DSIR BPF shows good agreement with the simulation data obtained by full‐wave EM simulations using Zeland IE3D ver. 10.06. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1059–1063, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21600
Quasi‐constant‐sensitivity VCO with offset‐tuning PN junction varactor array
Authors: Lee Sung‐Huang , Chiang Yueh‐Ta , Chiou Hwann‐Kaeo
Published: April 2006

A quasi‐constant‐sensitivity voltage‐controlled oscillator (VCO) using an offset‐tuning junction varactor array is demonstrated with low standard deviation of 4.5 MHz/V and average sensitivity of 41 MHz/V. The varactor array utilizing PN‐junction varactors provides high‐linear capacitor‐voltage response and low sensitivity variation. The VCO has a figure‐of‐merit (FOM) value, FOMKvco, of 0.11 and phase noise of −120 dBc/Hz at 1‐MHz offset. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1063–1066, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21601
Multiwavelength correlator for optical header recognition based on arrays of fibre Bragg gratings
Authors: Aljada Muhsen , Zheng Rong , Alameh Kamal , Al‐Begain Khalid
Published: April 2006

We demonstrate a novel optical correlator for multiwavelength header recognition employing arrays of fibre Bragg gratings (FBGs). One FBG array is used to appropriately delay the entire different header wavelengths, and the others are used as a header bank, in which each one is designed with a different wavelength profile. The proof of principle of the optical correlator is experimentally demonstrated and verified for 4‐bit header patterns at 2.27 Gb/s. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1066–1069, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21602
Multiband diamond shaped Sierpinski gasket monopole antenna
Authors: Mirkamali Ali , Hall Peter S. , Soleimani Mohammad
Published: April 2006

A multiband diamond‐shaped Sierpinski gasket monopole antenna is described. The radiation pattern of wideband monopole antennas like the circular‐disk and diamond monopole antennas degrades as frequency increases. In this paper, several cutouts based on the Sierpinski gasket geometry are made in the diamond monopole antenna in order to improve the radiation pattern of the antenna. It is experimentally shown that a multiband diamond‐shaped Sierpinski gasket monopole antenna with a significant improved radiation pattern can be achieved by making cutouts in the diamond monopole antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1069–1073, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21603
Simple derivation of dyadic Green functions of a simply moving, isotropic, dielectric–magnetic medium
Authors: Lakhtakia Akhlesh , Mackay Tom G.
Published: April 2006

Dyadic Green functions for time‐harmonic fields in a homogeneous, isotropic, dielectric–magnetic medium, moving with constant velocity, are derived by first implementing a simple transformation and then using the dyadic Green functions available for uniaxial dielectric–magnetic mediums. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1073–1074, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21604
Optimization of arbitrarily shaped dielectric axisymmetric horns through finite elements and the annealing algorithm
Authors: Monge Javier , Cid Juan M. , Gil José M. , Zapata Juan
Published: April 2006

This work addresses the design of dielectric axisymmetric horns with arbitrarily shape profile. The optimization is carried out by an adaptive version of the simulated annealing (SA) algorithm. In this way we avoid local minimum. No information about initial shape is introduced. The analysis is performed by a hybrid method based on the segmentation technique, the finite‐element method and a matrix Lanczos–Padè algorithm (SFELP), adapted to problems with axial symmetry. A set of example designs are presented to verify the technique. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1074–1079, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21605
New accurate analytical analyses of shielded planar transmission lines
Authors: Duyar Mehmet , Akan Volkan , Yazgan Erdem , Bayrak Mehmet
Published: April 2006

In order to calculate the quasi‐static TEM parameters of shielded coupled coplanar waveguides (SC CPWs) and shielded broadside‐coupled coplanar waveguides (SBC CPWs), closed‐form analytical formulas are obtained and presented using conformal‐mapping techniques. The variation of electrical parameters with respect to different physical dimensions is observed for each type of transmission lines under investigation. The obtained results are also confirmed by comparison with the results in the literature. Further verification has been realized via Sonnet electromagnetic‐circuit solver software. The proposed method in this study is thus well proved by these compared results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1079–1085, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21606
Scattering and radiation characteristics of step discontinuity in a double‐negative (DNG) slab waveguide operating in the evanescent surface mode
Authors: Huang Meng , Xu Shanjia
Published: April 2006

The scattering and radiation characteristics of a step discontinuity in a double‐negative (DNG) slab waveguide operating in the evanescent surface mode are analyzed by a method which combines the rigorous mode‐matching method with multimode network theory. In the analysis, the radiation problem is transformed into a propagation problem so as to tremendously simplify the calculation procedure. The dispersion properties of the grounded planar DNG slab waveguide for ordinary and evanescent surface modes are examined, from which the left‐hand property of the operating mode is verified. The relative scattered power and radiation pattern of the step discontinuity are given for the first time, from which the backward radiation of the stepped DNG guide is clearly demonstrated. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1085–1088, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21607
Use of extended ground plane to improve the performance of a slot‐loop antenna with narrow outer conductor
Authors: Song Yuming , Modro Joseph C. , O'Riordan Pauline , Wu Zhipeng
Published: April 2006

The performance of a slot‐loop antenna with a very narrow outer conductor can be significantly improved by connecting to an extended ground plane whose length is a quarter wavelength. The antenna has a reduced size and wider impedance bandwidth. Simulations have been carried out in the one‐wavelength and two‐wavelength modes and confirmed by experiments. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1088–1092, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21608
A wideband printed planar monopole for mobile handsets
Authors: Lin Shun‐Yun
Published: April 2006

This paper presents the design of a wideband printed monopole antenna with inductance loading. This design introduces a loading inductor aimed at decreasing the lowest frequency of the impedance bandwidth, while adjusting the ratio of the patch's length to width in order to increase the highest frequency. The experimental results all demonstrate that the two techniques play a key role in widening the antenna's bandwidth so that it can cover various wireless communication systems. The design's bandwidth covers the GSM (880–960 MHz), DCS (1710–1880 MHz), PCS (1850–1990 MHz), UMTS (1920–2170 MHz), and ISM (2400–2485 MHz) bands. The experimental results also indicate that the radiation patterns for all operating bands are omnidirectional on the azimuthal plane. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1092–1095, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21609
A new approach to the modeling of Si‐RFIC inductor
Authors: Das N. R. , Mitra Alakananda
Published: April 2006

In this paper, a new and simplified approach is proposed to model a radio frequency integrated circuit (RFIC) inductor in Si technology using Fuzzy Logic. An inductor structure made of a single‐layer metal ring fabricated on a silicon substrate is considered in the present analysis. The resistivity of the substrate layer, the thickness of SiO2 layer, and the frequency are considered as variable input parameters for the proposed model in order to calculate the effective inductance as output. The model results are then compared with the results obtained analytically using an equivalent circuit and reasonably good agreement is found within the scope of the model. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1095–1101, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21610
Ultra‐wideband low noise amplifier using a cascode feedback topology
Authors: Jung Jihak , Yun Taeyeoul , Choi Jaehoon
Published: April 2006

An ultra‐wideband (UWB) low‐noise amplifier (LNA) that consists of two cascode and shunt feedback stages is presented. The measurement results show the maximum gain (S21) of 11.9 dB with the 3‐dB band from 2 to 6.5 GHz and return losses (S11, S22) of less than −7.8 dB from 2 to 11 GHz. In addition, the fabricated LNA achieves the average noise figure (NF) of 4.5 dB from 2 to 10 GHz, which value is much lower than previously reported state‐of‐the‐art UWB amplifiers. The input‐referred 3rd‐order intercept point (IIP3) and the input‐referred 1‐dB compression point (P1dB) of the LNA are achieved as 4 and −5 dBm, respectively, while consuming 27 mW in the 0.18‐μm RF CMOS process. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1102–1104, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21611
Coupling and power dissipation in a coaxially excited TM01l mode cylindrical applicator with a spherical load
Authors: Komarov Vyacheslav V. , Yakovlev Vadim V.
Published: April 2006

This paper presents the results of 3D FDTD modeling of a 915‐MHz cylindrical structure with the TM01l mode excited by a coaxial line and intended for thermal processing of a spherical load (a fruit). Energy coupling is shown to be insensitive to the fruit's type and temperature, but dependent on its size and location and the loop's radius. The patterns of dissipated power are analyzed from the viewpoint of heating uniformity. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1104–1108, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21612
Further contributions to network optimization
Authors: Ben‐Ameur Walid , Gouveia Luis
Published: April 2006

This report surveys the papers presented at the International Network Optimization Conference (INOC2005), held in Lisbon, Portugal, March 2005. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 48(1), 1–6 2006
Route discovery with constant memory in oriented planar geometric networks
Authors: Chávez E. , Dobrev S. , Kranakis E. , Opatrny J. , Stacho L. , Urrutia J.
Published: April 2006

We address the problem of discovering routes in strongly connected planar geometric networks with directed links. Motivated by the necessity for establishing communication in wireless ad hoc networks in which the only information available to a vertex is its immediate neighborhood, we are considering routing algorithms that use the neighborhood information of a vertex for routing with constant memory only. We solve the problem for three types of directed planar geometric networks: Eulerian (in which every vertex has the same number of incoming and outgoing edges), Outerplanar in which a single face contains all vertices of the network, and Strongly Face Connected, a new class of geometric networks that we define in the article, consisting of several faces, each face being a strongly connected outerplanar graph. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 48(1), 7–15 2006
A linear time algorithm for the reverse 1‐median problem on a cycle
Authors: Burkard Rainer E. , Gassner Elisabeth , Hatzl Johannes
Published: April 2006

This article deals with the reverse 1‐median problem on graphs with positive vertex weights. The problem is proved to be strongly NP‐hard even in the case of bipartite graphs and not approximable within a constant factor (unless P = NP). Furthermore, a linear time algorithm for the reverse 1‐median problem on a cycle with linear cost functions (RMC) is developed. It is also shown that there exists an integral optimal solution of RMC if the input data are integral. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 48(1), 16‐23 2006
Numerical simulation of underfill encapsulation process based on characteritsic split method
Authors: Kulkarni Venkatesh M. , Seetharamu K. N. , Azid Ishak Abdul , Aswatha Narayana P. A. , Quadir Ghulam Abdul
Published: April 2006

Electronic packaging protects the integrated circuit chip from environmental and mechanical damages. Underfilling encapsulation is an electronic packaging technology used to reinforce the solder joints between chip and the substrate. For better mould design and optimization of the process, flow analysis during the encapsulation process is the first necessary step. This paper focuses on the study of fluid flow in underfilling encapsulation process as used in electronics industry. A two‐dimensional numerical model was developed to simulate the mould filling behaviour in underfilling encapsulation process. The analysis was carried out by writing down the conservation equations for mass, momentum and energy for a two‐dimensional flow in an underfilling area. The governing equations are solved using characteristic based split (CBS) method in conjunction with finite element method to get the velocity and pressure fields. The velocity field was used in pseudo‐concentration approach to track the flow front. Pseudo‐concentration is based on the volume of fluid (VOF) technique and was used to track fluid front for each time step.

A particular value of the pseudo‐concentration variable was chosen to represent the free fluid surface which demarcates mould compound region and air region. Simulation has been carried out for a particular geometry of a flip‐chip package. The results obtained are in good agreement with the available numerical and experimental values and thus demonstrate the application of the present numerical model for practical underfilling encapsulation simulations. Copyright © 2006 John Wiley & Sons, Ltd.