bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plane chiral waveguides with boundary impedance conditions
Authors: Oksanen Markku I. , Koivisto Päivi K. , Tretyakov Sergei A. 
Published: July 2007

AbstractThis article discusses electromagnetic wave propagation in chiral slab waveguides that are characterized by surface impedances of different types. The method applied makes use of the vector circuit theory and the related tangential field requirements on the slab surfaces. The method forms a coherent and solid approach to parallel‐plate waveguide analysis, since all cases considered can be solved from the same general eigenvalue equation. The theory is illustrated by numerical examples.
Comparison of the slope of the field at the reflection boundary of an edge‐induced and surface‐curvature‐induced microwave shadows
Authors: Rahnavard M. H. , Rusch W. V. T. 
Published: July 2007

AbstractUsing diffracted‐field formulas the slope of the field is evaluated at the reflection boundary of an edge‐induced shadow. Retaining high‐frequency terms the wavelength dependency is (λ)−1/2. Using a formula for the field near the turning point of an inflected surface the slope of the field at the reflection boundary is evaluated. Retaining high‐frequency terms, the wavelength dependency is (λ)−5/6 in this case. That is, the shadow for the surface‐curvature‐induced case gets sharper nearly twice as fast as for the edge‐induced case as the frequency increases. This slope is a measure of spillover into the shadow region.
Modeling wire dipoles in an infinite chiral medium and vertically oriented near a chiral half space
Authors: Bhattacharyya Asoke K. , Burke Gerald J. , Miller Edmund K. 
Published: July 2007

AbstractExtension and application of the NEC (numerical electromagnetics code) thin‐wire model to a wire dipole in an infinite chiral medium and vertically oriented near an interface between a free space and a chiral half space is described. This particular problem was chosen as one in a sequence leading to a capability for modeling wire antennas and scatterers of arbitrary geometry located on either side of, or penetrating such an interface. Results are presented as a function of medium chirality for the dipole in an infinite medium and as a function of chirality and height for the half‐space problem. An approximation for the latter problem which uses the reflection‐coefficient approximation (RCA) is compared with the rigorous treatment and found to produce acceptable results for the cases studied.
On the chiral riccati equation
Authors: Jaggard D. L. , Sun X. , Liu J. C. 
Published: July 2007

AbstractChiral media is characterized by a particular handedness and subsequent coupling between electric and magnetic fields as evidenced by the constitutive equations. Wave propagation in stratified chiral media is examined through an initial‐value approach which yields a matrix Riccati equation for the local reflection coefficient, valid for arbitrary angle of incidence. The first reported solution for reflection from an inhomogeneous chiral transition layer is given here.
Novel configuration of transmissive active star couplers using minimum erbiumdoped fibers and pump lasers
Authors: Liaw Jy‐Wang , Chen Yung‐Kuang 
Published: July 2007

AbstractIn this letter we propose a novel configuration by using the basic 4 × 4 active star coupler and the 2 × 2 fiber coupler as building blocks to construct a larger transmissive single‐mode fiber‐optic N × N coupler with gain using minimum erbium‐doped fibers and pump lasers. This configuration provides three main advantages, i.e., high cost effect, pump wavelength independence, and configuration flexibility. The 64 × 64 active star coupler with 4‐dB net gain using moderate pump power is also discussed. It is found that the saving of total cost of the proposed configuration can be more than 55% and 40% of those used previously [1], for 980‐ and 1480‐nm pump lasers, respectively.
Radiation of elementary dipole sources in stratified chiral media
Authors: Cheng Dajun , Cheng Jihua , Xue Liangjin 
Published: July 2007

AbstractEM radiation of the arbitrarily oriented elementary dipole sources, both electric and magnetic types, embedded in stratified chiral media is investigated using the matrix analysis, in conjunction with the Fourier transformation techniques for the observation points not near the excited sources.
Perturbation theory for a cavity resonator with a bi‐isotropic sample: Applications to measurement techniques
Authors: Tretyakov Sergei A. , Viitanen Ari J. 
Published: July 2007

AbstractResonator measurement techniques for exploring electromagnetic parameters of bi‐isotropic (nonreciprocal chiral) materials are discussed. The bi‐isotropic materials are the most general linear isotropic materials, and the corresponding constitutive relations are governed by four parameters. A theory of resonator measurement techniques, based on the perturbation analysis, is developed. It is shown that the complex permittivity, permeability, and nonreciprocity (Tellegen) parameter of a small sample can be determined by measuring resonant frequency shifts in a rectangular resonator. To measure the nonreciprocity parameter, a method utilizing a rectangular resonator with two degenerated modes is proposed.
Vernier fiber double‐ring resonator using degenerate two‐wave mixing
Authors: Ja Y. H. 
Published: July 2007

AbstractWe propose the use of degenerate two‐wave mixing in a Vernier optical fiber double‐ring resonator which consists of two single‐coupler fiber rings in series. With the degenerate two‐wave mixing, the Vernier operation can be achieved. In consequence, the effective free spectral range increases significantly and the signal beam is amplified.
A reciprocal phase shifter using novel pseudochiral or ω medium
Authors: Saadoun Mamdouh M. I. , Engheta Nader 
Published: July 2007

AbstractHere we introduce an idea for a reciprocal phase shifter using a novel class of material, which we name pseudochiral or ω medium. We describe this complex material electromagnetically by a set of bianisotropic constitutive relations, and present the physical insights into the coupling mechanism exhibited in such media. We analyze theoretically the dispersion characteristics of guided modes in a rectangular waveguide loaded partially with a slab of this material. It is shown that the propagation constant β of guided modes can be shifted due to coupling coefficients present in the medium. It is also shown that, unlike the case of magnetically biased ferrite‐loaded waveguide, the dispersion relations here are independent of the direction of propagation, and thus reciprocal phase shifting can be achieved. Potential applications and motivations behind this study are also mentioned.
Microwave imaging for dielectric objects under the born approximation based on projection
Authors: Suh Kyoung‐Whoan , Kim Sang‐Gi , Kim Se‐Yun , Ra Jung‐Woong 
Published: July 2007

AbstractMicrowave imaging for dielectric objects under the Born approximation is suggested by using the computerized tomography based on projection. Limiting factors of degradation in reconstructed images are identified and explored in terms of projection function and necessary condition on the first‐order Born approximation. To illustrate the usefulness of the presented method, simulation and experiment are performed in this article.
Circular microstrip antenna on a spherical surface
Authors: De Castro Lima Antonio Cesar , Descardeci José Ricardo , Giarola Attilio José 
Published: July 2007

AbstractA theoretical development for the analysis of a circular microstrip antenna on a spherical surface is described here. It consists of using the cavity model with magnetic side walls and the dyadic Green's function formulation. Expressions for calculating the resonant frequency and input impedance are given. A particular example with the antenna operating in its fundamental mode is examined. The characteristics of this antenna, including its radiation pattern, are presented.
Design, analysis, and development of a high power, low‐loss lumped coupler for vhf applications
Authors: Agarwal A. , Kakatkar S. S. , Sarkar B. K. 
Published: July 2007

AbstractLumped constant branch line couplers are analyzed and compared with coaxial branch line couplers. The effect of resistances associated with inductors and capacitors on the coupler's performance is studied. Three high‐power lumped couplers of 3 dB, 6 dB, and 10 dB are designed at 53 MHz. Insertion loss of less than 0.1 dB and 40‐kW peak power handling capability is achieved.
Bend loss of step‐index slab waveguides with a trench section
Authors: Yamauchi Junji , Ikegaya Morihiko , Nakano Hisamatsu 
Published: July 2007

AbstractAn optical waveguide bend with a trench section whose refractive index is smaller than that in the cladding is investigated to reduce bend loss. The appropriate location and width of the trench are determined using the beam propagation method. It is found that the attenuation constant shows a minimum value when the trench is made around the radiation point where the field becomes radiative.
Analysis and measurement of mutual coupling between two series‐fed electromagnetically coupled transverse dipoles
Authors: Tessereau S. , Floc'h J. M. , Legay H. , Citerne J. 
Published: July 2007

AbstractCalculations and measurements of mutual coupling between two series‐fed dipoles electromagnetically coupled transverse dipoles versus element spacing is presented. Calculations are based on an integral equation technique combined with a two‐port model of the coupled elements. An excellent agreement between theoretical and experimental results is observed.
Effect of imperfectly conducting surface of scatter on its radar cross section
Authors: Zhendong Shi , Chunsheng Ding 
Published: July 2007

AbstractThe scale‐down model testing of radar cross section for imperfectly conducting bodies requires physical similarity between models and prototype. Practically, it is often impossible to satisfy all the requirements at the same time; so it is necessary to study the effect of imperfectly conducting surface of scatter on its RCS. Dimensional analysis and theory of the model are used. As a result, relationship between σ/λ2 and λs is obtained, and the comparison between theoretical and experimental values for a cylinder coated with absorbent materials is given.
δmax detection of multipulse signaling in noisy optical channels
Authors: Fares D. A. , Abul‐Shohoud W. H. , Raslan N. A. , Nassef M. A. 
Published: July 2007

AbstractOptical communication has recently been given a great deal of attention because of its anticipated contribution in increasing our data transmission capability. δmax detection of Reed‐Solomon coded PPM (RSPPM) signaling has been seen as a reliable detection technique [1]. In this article we extend the application of this detection technique to the coded Steiner‐triple pulse format, which has recently proved its outstanding features [2, 3]. It is shown here that an improved performance (with respect to RSPPM), in addition to modest bandwidth expansion and efficient transmission bandwidth, are obtained.
Temperature dependence of schottky versus backward diodes for radiometry applications
Authors: De Maagt Peter J. , Buss Tom F. , Van Roer Theo G. De 
Published: July 2007

AbstractIn this article the temperature behavior of Schottky and backward diodes operating as square‐law detectors at microwave frequencies is presented. To make a quantitative comparison between both diodes possible, the most important diode parameters are discussed. The criteria for comparison are the voltage sensitivity and the video resistance. © 1992 John Wiley & Sons, Inc.
Optimization of pulse radiation from a simple antenna using resistive loading
Authors: Maloney James G. , Smith Glenn S. 
Published: July 2007

AbstractThe performance of a simple antenna, the open‐ended parallel‐plate waveguide, is optimized for pulse radiation by including a section of waveguide with tapered resistive loading. The novelty of the optimization is that the resistive loading is not only used in the traditional sense to reduce internal reflections, but the frequency dispersion inherent in the loading is also used to compensate for the distortion of the pulse on radiation from the open end. The analysis and optimization are performed using the finite‐difference time‐domain (FDTD) technique. The approach introduced here for optimizing this simple radiator should be applicable to more complex, practical antennas. © 1992 John Wiley & Sons, Inc.
The constitutive parameters of a lossy chiral slab by inversion of plane‐wave scattering coefficients
Authors: Cloete Johannes Hendrik , Smith Anthonie Gronum 
Published: July 2007

AbstractIt is shown how the three complex constitutive parameters of a lossy, homogeneous chiral slab may be obtained from its scattering parameters for illumination by a normally incident, linearly polarized plane wave. The method involves mathematical inversion of the scattering parameters and the result is an explicit, noniterative algorithm which yields the unknown constitutive parameters directly. © 1992 John Wiley & Sons, Inc.
Spectral domain analysis of rectangular microstrip antennas with an air gap
Authors: Fan Zhibo , Lee Kai‐Fong 
Published: July 2007

AbstractA spectral domain analysis of the rectangular microstrip antenna with an air gap is presented. Numerical results are given on input impedance, resonant frequency, and radiation patterns. It is found that, as the air gap width increases, both the resonant frequency and the impedance bandwidth increase, accompanied by a decrease in beamwidth. © 1992 John Wiley & Sons, Inc.
H‐scattering of thin‐film modes from periodic gratings of finite extent
Authors: Andrenko Andrey S. , Nosich Alexander I. 
Published: July 2007

AbstractDielectric thin‐film guided mode scattering from a finite‐element periodic grating of circular wires or circularly curved metal strips is considered. An accurate solution method is developed and results of computations for the H case are given. © 1992 John Wiley & Sons, Inc.
Complete characterization of MESFET Ids nonlinearities for intermodulation analysis
Authors: Pedro José C. , Perez Jorge 
Published: July 2007

AbstractThis work shows that an accurate characterization of the nonlinear distortion of a GaAs MESFET, does not allow the common approach of splitting the Ids, (Vds, Vds) current in two voltage‐dependent nonlinear current sources, Gm(Vgs) and Gdx(Vds). It is shown that the cross terms of the Ids Taylor series expansion can give an important contribution to the MESFETs intermodulanon distortion behavior. A laboratory procedure for the complete characterization of that element is given. © 1992 John Wiley & Sons, Inc.
Microwave active filter using GaAs monolithic floating active inductor
Authors: Zhang Guang Fei , Villegas M. L. , Ripoll C. S. , Gautier J. L. 
Published: July 2007

AbstractA broadband tunable microwave floating active inductor is proposed. Its application in the microwave active filter is presented. The design technique is to replace the passive inductor in the conventional LC ladder filter by the proposed floating active inductor. These active filters can, therefore, be implemented in full MMIC form. © 1992 John Wiley & Sons, Inc.
Analysis and development of a broadband interconnect for microstrip lines
Authors: Luong Giam‐Minh , Chang Kai 
Published: July 2007

AbstractAn analysis of an interconnect between two microstrip lines is presented. The interconnect is based on a narrow rectangular slot on the common groud plane of two microstrip lines. A moment method procedure is applied to several integral equations that were formulated by Green's functions of the grounded dielectric slabs and unknown electric and magnetic currents. Low insertion loss over an octave bandwidth was achieved for this interconnect. The theoretical results agree very well with measurements. © 1992 John Wiley & Sons, Inc.
Determination of the transverse delays in the GaAs/AIGaAs modfets
Authors: Goel A. K. , Xu Wei 
Published: July 2007

AbstractWe have developed a computer‐efficient algorithm and the related CAD‐oriented software to calculate the transverse propagation delays in a GaAs/AlGaAs MODFET. The model has been used to study the dependence of these delays on the various MODFET parameters. The results can be utilized for the optimization of high‐speed circuits. © 1992 John Wiley & Sons, Inc.
Design parameters of asymmetric edge‐coupled microstrip open‐end discontinuities
Authors: Martel J. , Boix R. R. , Horno M. 
Published: July 2007

AbstractA lumped capacitance equivalent circuit is used to characterize the asymmetric edge‐coupled microstrip discontinuity in the case in which the conducting strips are embedded in a multilayered anisotropic medium. The Galerkin method in the spectral domain is employed to determine the excess charge density on the strips of the discontinuity. Original results are provided for the general asymmetric discontinuity in conventional and suspended configurations. © 1992 John Wiley & Sons, Inc.
Triadic cantor target diffraction
Authors: Jaggard D. L. , Spielman T. 
Published: July 2007

AbstractElectromagnetic wave interactions with a triadic Cantor target are investigated as an example of diffraction by fractal apertures. Of interest is the evolution of diffraction pattern with fractal growth for these self‐similar structures, and the development of efficient methods of calculation. It is found that such structures possess self‐similar diffraction patterns and that simple analytic solutions can be found for these geometries. The solutions also exhibit a sense of self‐similarity in their computation. © 1992 John Wiley & Sons, Inc.
A boundary integral approach to the scattering from periodic gratings
Authors: Moore John , Ling Hao , Graf Urs U. , Jaffe Daniel T. 
Published: July 2007

AbstractA boundary integral formulation is presented for computing the scattering from infinite periodic gratings. Periodic boundary conditions and expansion of the fields in terms of Floquet harmonics allow the boundary integral formulation to treat just a single period of the infinite grating. Numerical results for a blazed grating designed for use at infrared wavelengths are presented and shown to be in good agreement with a series of measurements. © 1992 John Wiley & Sons, Inc.
Phase grating: Analytical formulas for the near field
Authors: Arrizón Victor , Ojeda‐Castañeda J. 
Published: July 2007

AbstractWe present two simple analytical formulas that describe the irradiance distribution, at certain distances, of any phase grating. Our general results are illustrated with two novel examples: the irradiance distribution at the near field of a low‐frequency blazé grating, and that of a phase grating with a triangular profile. © 1992 John Wiley & Sons, Inc.
A formulation for surface impedance boundary conditions using the finite‐difference time‐domain method
Authors: Kashiwa Tatsuya , Chiba Osamu , Fukai Ichiro 
Published: July 2007

AbstractIn this article, a new formulation for surface impedance boundary conditions is carried out using the finite‐difference time‐domain method. In this formulation, the boundary conditions expressed by the equivalent circuit are only considered in a one‐dimensional space. For simplicity, the validity of the formulation is also shown and discussed. © 1992 John Wiley & Sons, Inc.
Threshold detection of a quadruple pulse signaling in noisy optical channels
Authors: Fares Doaa A. , Rasian Nabil A. , Kaseb Hassan M. 
Published: July 2007

AbstractIn references [1, 2], triple multipulse position modulated (TPPM) signaling has been introduced as a very reliable format for optical communication channels. In this article, such a multipulse model is extended to the Steiner quadruple pulse system (SQS). Considering a threshold demodulation scheme for a fully degraded optical channel, performance of the Reed‐Solomon coded model is evaluated and compared to the standard coded PPM, when similar information efficiency and closest bandwidth expansion are allowed. The gained results are very interesting. © 1992 John Wiley & Sons, Inc.
A technique for the large‐signal characterization of transistors
Authors: Tsang Kim Fung , Yip Peter C. L. , Morgan Gwyn B. 
Published: July 2007

AbstractA novel method for the characterization of transistors operating in the nonlinear region has been developed. A new measurement method is proposed and the formulation for the characterization has been developed. Calculated results based on the proposed method are promising when compared to measured data. © 1992 John Wiley & Sons, Inc.
Excitation of three‐dimensional solitary waves from a nonlinear slab waveguide
Authors: Liu Shuh‐Fang , Wang Way‐Seen 
Published: July 2007

AbstractSolitary‐wave excitation in a slab waveguide bounded by two different non‐Kerr‐like media exhibiting saturable self‐focusing nonlinearity is investigated. From numerical calculation it is found that solitary waves are emitted from the nonlinear interfaces. Moreover, mutual interaction between them is observed if the excitation is larger. The simulated results are useful for the study of three‐dimensional solitary waves. © 1992 John Wiley & Sons, Inc.
Grid bandpass filters for quasioptical frequency multiplier array application
Authors: Liu Hong‐Xia L. , Sjogren L. B. , Luhmann N. C. 
Published: July 2007

AbstractA two‐grid approach for quasioptical bandpass filter design is presented. In this design, an inductive/capacitive grid on one side of a dielectric substrate is transformed to an effective capacitive/inductive reactance at the other grid plate, producing a parallel resonant circuit. Two bandpass filters for use in the millimeter region have been fabricated. Low‐loss power transmission at the design frequencies has been achieved with good quantitative agreement with theory. © 1992 John Wiley & Sons, Inc.
Capacitance of rectangular lines with cross inner conductor, considering angular offset between conductors, side magnetic walls, and off‐centered inner conductor
Authors: Costamagna Eugenio 
Published: July 2007

AbstractVarious coaxial line structures having a cross section in which an equiarmed cross is concentric with an external square are analyzed by means of numerical inversion of the Schwarz‐Christoffel conformal transformation, considering angular offset between conductors and electric or magnetic side walls. Geometries with rectangular outer conductor and off‐centered inner cross conductors are considered. Previous works by Riblet [1] and Lin [2–4] are generalized or completed. © 1992 John Wiley & Sons, Inc.
Backscattering reduction of corner reflectors using scs technique
Authors: Ajaikumar V. , Jose K. A. , Aanandan C. K. , Mohanan P. , Nair K. G. 
Published: July 2007

AbstractReduction of radar cross‐section of dihedral corner reflectors using simulated corrugated surface (SCS) is reported. This technique is found to be more effective in the reduction of RCS or corner reflectors for normal incidence. A typical reduction of 40–50 dB is achieved using this method. © 1992 John Wiley & Sons, Inc.
Mutual coupling between rectangular microstrip patch antennas
Authors: Huynh Tan , Lee Kai‐Fong , Chebolu Siva Rao , Lee R. Q. 
Published: July 2007

AbstractA comprehensive study of the mutual coupling between two rectangular microstrip patch antennas is presented. Using the cavity model, numerical results for both mutual impedance and mutual coupling parameter are given for the E‐plane, H‐plane, diagonal, and perpendicular orientations. The effects of substrate thickness, substrate permittivity, and feed positions are discussed. © 1992 John Wiley & Sons, Inc.