bluuebunny/crossref_metadata_2025_split huggingface dataset:
Full‐wave analysis of superconducting microstrip for MMIC applications
Authors: Paleczny E. , Legier J. F. , Kennis P. , Pribetich P. 
Published: July 2007

AbstractIn this article we take into account the influence of the superconducting nature of the strip in order to study the behavior of the superconducting microstrip line by means of two numerical methods. The first one is the spectral domain approach modified by the surface impedance concept and the second one is the modified mode‐matching technique. This last one allows more accurate simulation of the presence of the superconducting strip without using surface impedance approximation. In a second step we present the corrections brought to the modified SDA in order to obtain accurate results by this more versatile numerical method, which consumes small amounts of CPU time.
Role of complex modes in coplanar‐waveguide‐to‐coplanar‐waveguide discontinuity calculations
Authors: Kooi P. S. , Leong M. S. , Widjojo Benny , Yeo T. S. 
Published: July 2007

AbstractThe existence of complex modes in the lossless symmetrical shielded coplanar waveguide is demonstrated. Complex modes are found to occur only within a range of frequency and structural parameters. It is shown that exclusion of these modes in the analysis of coplanar waveguide discontinuities can cause the imput reflection and transmission coefficients to converge to incorrect values, thus highlighting their importance in such problems.
Polarization agile microstrip array antenna element
Authors: Sangster A. J. 
Published: July 2007

AbstractA new microstrip antenna element is described which exhibits polarization agility. This is achieved by employing a T‐slot radiator which is driven by the edge fields of a balanced microstrip line. The balanced line can support two propagating modes, namely, an even mode and an odd mode, and by switching between these modes, the orthogonal arms of the T‐slot radiator are separately excited thus forming orthogonally polarized radiated fields. A microstrip patch antenna, which displays polarization agility using the same mechanism, is also described.
Vector potential green's function for a radially directed line dipole in open space
Authors: Butler Chalmers M. 
Published: July 2007

AbstractA vector potential Green's function for a radially directed line dipole (Figure 1) is derived. Methods for obtaining two‐dimensional Green's functions are available for the z‐directed line current and for the OS‐directed line dipole. With the results of this article available, the set of Green's functions for two‐dimensional sources in cylindrical coordinates is complete.
Design of ergodic electromagnetic cavities
Authors: Booske J. H. , Meng B. 
Published: July 2007

AbstractCavity Q's and reflection coefficients for cavities excited by single “ergodic” eigenmodes are quantitatively calculated based on the available expressions derived from the Hamiltonian formulation. The results are compared with those obtained for multimode excitation in large, “untuned” resonant cavities. Applications relevant to the microwave and millimeter‐wave regime are discussed. In addition to absorption spectroscopy and materials processing, ergodic cavities may used as radiation‐beam dumps for high‐power testing of millimeter‐wave sources.
A wide‐band class‐b amplifier using tapered interdigital power combiners
Authors: Tsai M. C. 
Published: July 2007

AbstractA tapered interdigital equal‐split coupler has been designed and fabricated in a planar structure. Multioctave bandwidths of equal power splits and 0° and 180° phase differences were obtained. Over 20‐dB improvement of the second harmonics generated from a Class‐B GaAs amplifier using this coupler as a combiner was demonstrated. This approach has potential applications for GaAs MMIC amplifiers and mixers.
Microwave measurement of complex permittivity of dielectric ring resonators using higher‐order resonant modes
Authors: Kim Jeong Phill , Park Wee Sang 
Published: July 2007

AbstractA theory and measurement technique to determine the complex permittivity of microwave dielectric ring resonators placed between two conducting plates is presented. The resonant frequencies and unloaded quality factors for higher‐order modes, and physical dimensions of the resonator are used to expand the measurement frequency span.
Vectorial analysis of triple rib guide heterostructures as wavelength duplexers
Authors: Stuwe Peter , Unger Hans‐Georg 
Published: July 2007

AbstractAn integrated optical duplexer with three rib waveguides is investigated theoretically by a two‐dimensional mode‐matching technique with modal fields obtained by the method of lines. The results are compared with those of a one‐dimensional analysis and show the range of applicability of the effective index method. An optimized duplexer for separation of the 1.3‐μm band from the 1.55‐μm band is only 290 μm long and has a 1‐dB bandwidth of 0.15 μm. A complete one‐dimensional mode expansion shows that radiation has no significant influence on the duplexer characteristics. They are also nearly independent of polarization.
Combined perturbation and wiener‐hopf analysis of the diffraction by a finite sinusoidal grating
Authors: Kobayashi Kazuya 
Published: July 2007

AbstractPlane‐wave diffraction by a finite sinusoidal grating is analyzed approximately using the Wiener‐Hopf technique combined with the perturbation method. Scattered far field is derived with the aid of the saddle‐point method and scattering characteristics of the grating are discussed via numerical computations of the far‐field patterns.
Quasi‐tem and full‐wave approaches for coplanar multistrip lines including gyromagnetic media longitudinally magnetized
Authors: Mesa F. , Horno M. 
Published: July 2007

AbstractThe quasi‐TEM and full‐wave algorithms developed in this article enable us to deal with a coplanar transmission line including an arbitrary number of conductors and lossy magnetic and/or dielectric layers. The quasi‐TEM and the full‐wave approaches are compared in order to establish reliable criteria concerning the validity range of the quasi‐TEM analysis. The exact knowledge of this range permits us to study new MIC or MMIC configurations combining gyromagnetic, ferrimagnetic‐semiconductor, and dielectric layers by means of the simple quasi‐TEM model.
The recurrence matrix technique for the arbitrary millimeter‐wave and microwave planar transmission lines
Authors: Qiu C. M. , Ren W. , Lin W. 
Published: July 2007

AbstractThe analysis of the APTL has been completed by using a new, general recurrence matrix technique based on the method of lines. This new technique has laid the foundations for the analysis of the new type of planar structures. Numerical results for three complicated structures show that the developed CAD software is accurate, practical, and general.
Investigations on arrays of nonidentical radiators
Authors: Raju G. S. N. , Rao P. M. , Gottumukkala K. R. , Chakraborty Ajoy 
Published: July 2007

AbstractThe narrow beams with very low sidelobes are generated from an array of nonidentical elements. The array considered in the present work is found to be more advantageous than the array of identical elements in terms of main beamwidth and side‐lobe levels, excitation levels being uniform in both cases.
Novel rotational characteristics of radiation patterns of chirostrip dipole antennas
Authors: Pelet Philippe , Engheta Nader 
Published: July 2007

AbstractWe present certain novel characteristics of the radiation pattern of a chirostrip dipole antenna which consists of a short horizontal dipole antenna on a grounded chiral substrate. Chiral materials are characterized by constitutive relations D = ϵeE + iϵcB and H = B/μc + iϵeE. In our theoretical analysis we show that the radiation pattern of a simple chirostrip horizontal dipole undergoes a rotation around the axis normal to the substrate and that this rotation depends on the value of the chirality iϵe. Applications of this novel antenna are mentioned.
On the harmonic balance analysis of almost‐periodic autonomous nonlinear circuits with dynamic nonlinear characteristics
Authors: Camacho‐Peñalosa C. , Martin‐Funke E. 
Published: July 2007

AbstractAnalytical expressions for the efficient computation of sensitivities with respect to fundamental periods in dynamic nonlinear characteristics under multitone excitation are presented. Almost‐periodic oscillations in the forced Van der Pol oscillator are computed to illustrate the capability and efficiency of the resulting harmonic balance technique.
Wavelength dependence of the optical control of a hemt oscillator
Authors: Romero M. A. , Bangert A. , Zhang X. , Herczfeld P. R. 
Published: July 2007

AbstractThe direct optical control, tuning, FM modulation, and injection locking of a 2–GHz HEMT oscillator using a semiconductor laser (α = 0.85 μm) is reported. An optical tuning range of 4.3 MHz and an optical injection locking range of more than 0.55 MHz at fundamental frequency were achieved. For the first time an experimental study relating the photoresponse mechanisms in the HEMT to the wavelength of the incident light is presented. It is shown that for the 0.85–μ‐wavelength illumination the photoconductive effect dominates the optical response of the device, while for 0.633–μm illumination the photovoltaic effect prevails [1]. The photoconductive mechanism, which is smaller but faster, is more suitable for high frequency applications such as direct optical injection locking.
Proposal of a high‐capacity all‐optical tdma network
Authors: Matera F. , Romagnoli M. , Settembre M. , Tamburrini M. 
Published: July 2007

AbstractA scheme of an all‐optical synchronous TDMA network is proposed with the demultiplexing process obtained by means of an optical gate based on the second harmonic generation process and pulse propagation in the soliton regime. Such a network would present a maximum throughput of 125 Gbls.
Electromagnetic coupling between coplanar waveguide and microstrip antennas
Authors: Simons Ralnee N. , Lee Richard Q. , Lindamood Glenn R. 
Published: July 2007

AbstractElectromagnetic coupling between coplanar waveguides (CPW) and microstrip patch antennas has been investigated for two feed configurations: (1) direct aperture‐coupled feeding of a patch antenna by a CPW feed, and (2) proximity‐coupled feeding of a patch antenna by a microstrip line which is aperture coupled to a CPW feed. Results indicate that both feeding approaches are feasible and yield high coupling efficiency.
Dipole radiation in the presence of a grounded chiral slab
Authors: Cheng Dajun , Xue Liangjin 
Published: July 2007

AbstractRadiation of an electric dipole located along an arbitrary direction in the presence of a grounded chiral slab is investigated using matrix analysis in conjunction with Fourier‐transform techniques. Numerical results of the radiation pattern of such a structure are plotted both for vertical and parallel cases.
Optoelectronic chip implementation of a bipolar quadratic associative memory
Authors: Lin Senmao , Chen Caisheng 
Published: July 2007

AbstractThe optoelectronic chip implementation of a bipolar quadratic associative memory is reported. A new version of the bipolar quadratic neural network is proposed and an optoelectronic system based on two inner‐product multipliers is used. The quadratic associative memory described in this article has a larger storage capacity and a higher error‐correction capability than those of the unipolar one. Experimental results are also given.
Theoretical and experimental study on the linear microstrip patch antenna array technique using e‐plane gap coupling
Authors: Cho Young Ki , Hwang Oon Ha , Lee Kwang Eok 
Published: July 2007

AbstractThe purpose of this article is to present a theoretical method for analyzing an E‐plane gap‐coupled rectangular microstrip array antenna which consists of one center‐fed patch and several parasitic elements by use of the transmission‐line model and the equivalent circuit parameters for the capacitive gap between microstrip patch and the open end of the patch. Antenna characteristics such as radiation pattern and return loss are computed theoretically and compared with experimental results for illustrating the usefulness of this method.
Perforated dielectric lens
Authors: Lee C. S. , Lee S. W. , Davis R. , Tsui J. 
Published: July 2007

AbstractThe dielectric lens for an ideal focusing effect requires a continuously varying dielectric constant. In this article, the varying dielectric constant is simulated by drilling holes in the lens. The gain improves significantly (˜3 dB) by placing holes in the lens when the lens diameter is much larger than the wavelength (>10 λ) but the hole size is small (<0.25 λ).
Non‐gaussian beams in direct coupling from laser diodes into optical waveguides via small gaps
Authors: Lee Keh‐Yi , Wang Way‐Seen 
Published: July 2007

AbstractIn a direct coupling from a laser diode into an optical waveguide, some mathematical models about field profile, spot size, and phase variation of the optical beam within the small diode‐waveguide gap can be used to fit the experimental data much better than those of the Gaussian beam. These models are expected to be useful in the numerical simulation of the losses of the diode‐to‐waveguide or diode‐to‐fiber coupling.
A novel mesfet‐compatible gaas optoelectronic switch
Authors: Riesz Ferenc , Szentpáli B. , Gottwald P. , Németh‐Sallay M. 
Published: July 2007

AbstractPhotoconductive optoelectronic pulse‐forming switches have been fabricated from vapor‐phase epitaxially grown GaAs‐based layer structures. The fabrication process is compatible with the MESFET/MMIC technology. The light‐absorbing region is thinned by chemical etching, thus changing the actual carrier lifetime in this region. The switches showed off/on resistance ratios of about 500 even at about 0.1‐mW incident optical power. The pulse response of the devices is limited by the lifetime of charge carriers.
Electromagnetically coupled patch antenna—theoretical and experimental investigations
Authors: Karmakar Nemal C. , Bhattacharyya A. 
Published: July 2007

AbstractEquivalent circuit of an electromagnetically coupled (EMC) rectangular patch antenna is obtained using reciprocity. Theoretical results for the return loss are in good agreement with the experimental data. The model is simple both conceptually and computationally, and can be used to predict the performance of EMC antennas.
Input impedance of rectangular microstrip antennas with a dielectric cover
Authors: Fan Zhibo , Lee Kai‐Fong 
Published: July 2007

AbstractA theoretical and numerical analysis of the rectangular microstrip antenna with a dielectric cover is presented. Numerical results on input impedance are given, showing that the main effect of the dielectric cover is to reduce the resonant frequency, with only minor changes in the resonant resistance and the impedance bandwidth.
Comparative study of the galerkin and the least‐squares boundary residuals (lsbr) methods for the analysis of microwave integrated circuits (MICs)
Authors: Essaaidi M. , Boussouis M. 
Published: July 2007

AbstractIn this article a comparative study of the least‐squares boundary residuals (LSBR) and the Galerkin methods is presented. The study shows that both methods are relatively and rapidly convergent. A criterion of relative convergence is developed for the LSBR method. In addition, this method is shown not to yield spurious solutions, which are normally encountered with the Galerkin method. A systematic modes identification technique is also provided for the Galerkin method.
A recursive algorithm to compute the wave‐scattering solution of a finite‐strip array using an efficient plane‐wave basis
Authors: Chew W. C. , Lu C. 
Published: July 2007

AbstractA truncated, nonuniform, finite array of strips does not have a closed‐form solution. Using translational symmetry, a recursive algorithm that calculates the scattering solution with N log2 N computational complexity is described. The current distribution for the Hz polarization shows small‐length‐scale oscillations not present in the Ez polarization.
Refractive index control on the polarization sensitivities of semiconductor traveling‐wave laser amplifiers
Authors: Ghafouri Shiraz H. , Chu C. Y. J. 
Published: July 2007

AbstractWe have found that the polarization sensitivity of buried heterostructure traveling‐wave laser amplifiers can be minimized further by controlling the refractive index profile in its transverse plane, in addition to increasing the active layer thickness.
Influence of the drawing ratio and the relative index difference on propagation characteristics in single‐mode fibers with arbitrary refractive index profile
Authors: Gao Yangsheng 
Published: July 2007

AbstractSimple formulas are derived for the sensitivity of dispersion, mode field radii, and cutoff wavelengths in single‐mode fibers due to arbitrary variations of the drawing ratio and the relative index difference simultaneously. For calculations only the propagation characteristic spectrum of the ideal fiber is required. Some applications are given.
Microwave complex permittivity of rainwater in the 26–40‐ghz band
Authors: Kooi P. S. , Tran V. N. , Leong M. S. , Yeo T. S. 
Published: July 2007

AbstractThe complex permittivity of rainwater, which is required for the modeling of rain‐induced attenuation of electromagnetic waves, has been measured at Q band (26–40 GHz) using the infinite line impedance technique. The results obtained were found to differ slightly from those of distilled water.
The accurate variational analysis for the measurement of the complex dielectric constant of a sample rod inserted in a cavity
Authors: Liang C. H. , Xie Y. J. 
Published: July 2007

AbstractThis article derives a Lindell formulation based on a generalized variational principle. A complex dielectric constant measurement of a small‐loss dielectric rod using the Rayleigh—Ritz method gives accurate variational analysis. The concept of complex frequency ω is introduced in general, and the stability of the solution is discussed. When compared with the results of perturbation, it is concluded that the deviation of the algorithm is worthy of more attention.
Photoconductors as dynamic memory elements
Authors: McGinn V. P. , Smith B. C. 
Published: July 2007

AbstractIndustrial photoconductors are doped for large quantum yields. The resulting improvement in resistive dynamic range is accompanied by photocarrier traps. These traps enhance device hysterisis (or memory). The reduction in response speed mimics electrical reactance effects. This light history may be exploited in the construction of low‐frequency filters and oscillators.
A parallel‐series‐fed microstrip array with high efficiency and low cross‐polarization
Authors: Huang John 
Published: July 2007

AbstractA linearly polarized traveling‐wave microstrip array antenna is parallel and series fed by microstrip transmission lines. Excellent antenna efficiency is achieved by having proper impedance matching throughout the array and by properly utilizing the reflected power from the end of the array. Very low cross‐polarization radiation is achieved by exciting the patches and transmission lines with antiphase technique.
Laser ablated yba2cu3o7‐x high temperature superconductor coplanar waveguide resonator
Authors: Valco G. J. , Blemker A. R. , Bhasin K. B. 
Published: July 2007

AbstractWe have fabricated and tested several 8.8‐GHz coplanar waveguide resonators made from laser ablated YBa2Cu3O7‐b thin films on LaAlO3 substrates. A quality factor of 1250 at 77 K was measured. A correlation between the microwave performance of the resonators and the critical temperature and morphology of the films was observed.
Dual circularly polarized sequentially rotated microstrip array with high isolation
Authors: Hall P. S. 
Published: July 2007

AbstractSequentially rotated feeding improves the axial ratio and input VSWR bandwidths of circularly polarized arrays. However, when dual polarization is wanted, the method is shown not to improve isolation, as is the case for dual linearly polarized arrays. This deficiency is overcome by squinting the beam. Measured results for a small array confirm this and computations for large arrays indicate performance capabilities.
Broadband millimeter‐wave detector using dielectric image line
Authors: Kikuchi Kazuo 
Published: July 2007

AbstractThe broadband millimeter‐wave detector using a dielectric image line is presented. The detector mount is fabricated by a hot carrier diode and a triangular unipole antenna with tapered angle of 16 degree, 39‐degree flare angle and 3.4 mm length. A broadband millimeter‐wave 32–50‐GHz detector is obtained.
S‐band medium‐power mesfet amplifier with high stability
Authors: Samuel M. , Nawarange A. , Mahapatra S. 
Published: July 2007

AbstractIn this Letter a novel technique to design a FET amplifier with potentially unstable FETs is reported. A two‐stage FET amplifier with small signal gain of 20.4 ± 0.2 dB and power output of 23 dBm over the frequency band of 2.3–3.1 GHz is reported. Measured output/input VSWR are also reported.
Calculation of parameter tolerances of near‐zero dispersion step‐index fiber for a specified bandwidth
Authors: Marincic A. , Miletic D. 
Published: July 2007

AbstractIn this article we present a method for easy calculation of allowed monomode fiber parameter tolerances which guarantee operation around the zero dispersion wavelength. A statistical method is used to determine the relative tolerances δΔ/Δ, δa/a, and δλ/λ, for the specified minimum fiber bandwidth. Numerical results are presented for a step‐index fiber.
Radiation and scattering by thin wires with a dielectric coating—a finite‐difference time‐domain approach
Authors: Boonzaaler J. J. , Pistorius C. W. I. 
Published: July 2007

AbstractThis Letter discusses the computation of the scattering and radiation by thin wires with a nondispersive dielectric coating using the finite‐difference time‐domain method. A Fourier transform is then performed on the time‐domain results to obtain the scattering and antenna radiation patterns in the frequency domain.
Trade‐off design for high speed pulse propagation in microstrip lines
Authors: Voranantakul Suwan , Prince John L. 
Published: July 2007

AbstractParameter trade‐off for minimizing high‐speed pulse distortion on a microstrip line is investigated. The sensitivity of physical parameters to conductor loss, dielectric loss, and inflection frequency is first studied and then summarized in a compact and easy‐to‐use format. The results of this work will provide designers with simple and effective guidelines for designing microstrip lines with a reduced output signal distortion © 1992 John Wiley & Sons, Inc.
Determination of the permittivity and permeability of microwave resonators using two resonant modes
Authors: Park Wee Sang , Chun Joong Chang , Kim Bum Man 
Published: July 2007

AbstractAn electromagnetic theory and mathematical procedure to determine the permittivity and permeability of lossless microwave resonators using two resonant modes is presented. An illustrative example is given for a resonator with a relative permittivity of 10 and a relative permeability of 3. © 1992 John Wiley & Sons, Inc.
Computation of electromagnetic plane‐wave scattering from a curved dielectric shell using a physical optics approach
Authors: Janse Van Rensburg D. J. , Malherbe J. A. G. , McNamara D. A. 
Published: July 2007

AbstractA Physical optics computation is performed to obtain the electromagnetic backscatter from a dielectric half cylinder. Computed results are verified through comparison with accurate measured data. © 1992 John Wiley & Sons, Inc.