bluuebunny/crossref_metadata_2025 huggingface dataset:
Explanation of acousto‐optic frequency multiplication in amorphous materials
Authors: Taalbi Mustapha , Ishii T. K.
Published: July 2007

Observed anomalous acousto‐optic frequency multiplication in amorphous materials is explained for the first time. Theoretical models reviewed include the nonresonant standing‐wave model, the first‐order modulation model, and the second‐order modulation model. It is found that only the nonresonant standing‐wave model provides an explanation for the observed phenomena, and not the Other models. © 1993 John Wiley & sons, Inc.
Characterization of annealed proton‐exchanged LiNbO3 waveguides fabricated using toluic acid
Authors: Loi K. K. , Pun E. Y. B. , Chung P. S.
Published: July 2007

Annealing properties of proton‐exchanged optical waveguides in z‐cut LiNbO3 fabricated using toluic acid are reported. Variations in the surface refractive index and waveguide depth with annealing time are found to follow a power‐law relationship, and a minimum propagation loss of 0.23 dB/m is measured at 0.633‐μm wavelength. © 1993 John Wiley & sons, Inc.
Effects of chirality admittance on the cutoff wavelength of propagating modes in a chiral coaxial line
Authors: Wenyan Yin , Pao Li
Published: July 2007

The field distributions and cutoff equations of the propagating modes in chiral coaxial line are derived at first, and the effects of chirality admittance ξc, on the cutoff wavelengths of EHnm and HEnm are examined. The results show that the cutoff wavelengths of EHnl and HEnl (n = 0, 1, 4) are approximately proportional to ξc, and also, in chiral coaxial lines, the longitudinal components of electric and magnetic fields are always coupled as in parallel‐plate chirowave‐guides, etc.; TE, TM, or TEM modes cannot be supported. © 1993 John Wiley & sons, Inc.
A novel concept of intermodulation distortion linearization
Authors: Pedro Jose C. , Perez Jorge
Published: July 2007

In most cases, microwave amplifier linearization requires complex and voluminous circuitry of very critical tuning, which leads to poor cost effectiveness and poor reproducibility. In this article an innovative concept of IMD linearization, based on direct active device IMD characteristic shaping, is presented. Also, it is shown how recent advances in nonlinear MESFET modeling can be used to implement the idea. © 1993 John Wiley & Sons, Inc.
Frequency multiplication of acoustic signals with an optical fiber
Authors: Taalbi Mustapha , Ishii T. K.
Published: July 2007

An acousto‐optic modulator is made using an optical fiber placed on a ceramic piezoelectric transducer. The photodetected signals show frequency multiplication and phase shifting of the acoustic signals applied to the piezoelectric transducer depending on the lightwave beam incidence angle. The linear polarization of the lightwave is destroyed after passage through the fiber. The normalized lightwave transmission coefficient depends on the acoustic modulating signal frequency, and has values exceeding 1 at or near cross polarization. This is an anomalous phenomenon, letting one assume that pseudoamplification, or intensification, is occurring at the previously stated conditions. © 1993 John Wiley & Sons, Inc.
An efficient method for analyzing graded‐index optical fibers
Authors: Guerreiro And M. V. Das Neves , Faria J. A. Brandao
Published: July 2007

We describe a method for analyzing graded index optical fibers using a stepwise function approximation to model the core refractive index profile. For each homogeneous shell uncoupled radial equations for the longitudinal field components Ez and Hz are considered. Relationship between field solutions corresponding to core adjacent shells is established with the help of appropriate boundary conditions. Numerical results obtained with this method are presented and discussed, with special attention being focused on the analysis of the number of discretization steps necessary for achieving satisfactory core modeling. © 1993 John Wiley & Sons, Inc.
Analysis of electromagnetically coupled patch antennas
Authors: Fan Zhibo , Lee Kai‐Fong
Published: July 2007

A spectral domain full‐wave analysis is given for a class of electromagnetically coupled patch antennas with cylindrical geometries. Numerical results on the input impedances of the stacked circular disks and the ring‐loaded circular disk are in good agreement with published results in the literature. © 1993 John Wiley & Sons, Inc.
Comparison of multimode network and spectral domain analysis applied to metallic strips
Authors: Langley R. J. , El‐Sheikh A. N. A.
Published: July 2007

This Letter compares the results of two methods for predicting the scattering from periodic arrays of metallic strips. The first method is a full spectral domain analysis incorporating the sampling theorem, while the second is a multimodal network solution to the problem. Results are compared for thin and thick strips under both TE and TM wave incidence. It is shown that the multimode network solution is about five times more computationally efficient and yet yields virtually identical results. © 1993 John Wiley & Sons, Inc.
Local interconnection neural networks
Authors: Zhang Jiajun , Zhang Li , Yan Dapen , He Anzhi
Published: July 2007

Based on the Hopfield model, a new concept of the local interconnection neural network (LINN) is proposed. Compared with the global interconnection neural network (GINN), LINN offers a smaller interconnection matrix. © 1993 John Wiley & Sons, Inc.
A dielectric hybrid‐mode horn as a gaussian beam‐mode antenna in 3‐MM band
Authors: Dou W. B. , Sun Z. L.
Published: July 2007

A dielectric hybrid‐mode horn has been analyzed theoretically. The horn can support a balanced hybrid HE mode. The fields under the balanced hybrid condition have been expressed. By optimizing the structure parameters, the fraction of the power radiated into the fundamental Gaussian mode can reach about 98% over a wide frequency range in 3‐mm band. Drawbacks are the effects of dielectric losses. Thus the new horn represents an attractive alternative to the corrugated horn for forming the Gaussian beam in millimeter‐wave band. © 1993 John Wiley & Sons, Inc.
Optical pattern logic processing with one‐rule symbolic substitution
Authors: Liu Guoqlang Li Liren
Published: July 2007

In this article, one‐rule symbolic substitution is introduced to process 2D pattern logic. All the 16 possible logic gates of two input variables are designed. By using a combined system of a multiimaging unit and an optoelectronic morphological unit with two independent input planes of the control pattern and the input patterns, all the logic functions can be achieved by simply programming the control pattern. Experimental results are presented. © 1993 John Wiley & Sons, Inc.
Some focusing properties of chirped gratings at microwave frequencies
Authors: Christodoulou C. G. , Schmidt J. C.
Published: July 2007

This article presents a theoretical and experimental analysis of the focusing properties of metallic chirped gratings. These aperiodic gratings are designed to focus energy at a desired position by varying the strip width and strip spacing. The location of the individual strips, their width variation, distance of separation, and angle of incidence determine the focal point of the chirped grating. © 1993 John Wiley & Sons, Inc.
Free‐space techniques for biisotropic media parameter measurement
Authors: Tretyakov Sergei A. , Haliullin DamirY A.
Published: July 2007

Four scalar complex parameters (dielectric permittivity, magnetic permeability, chirality parameter, and nonreciprocity parameter) characterize general biisotropic materials. In this communication, possible techniques for material parameter measurement are addressed. Procedures are based on free‐space measurements of plane‐wave reflection from the transmission through a biisotropic slab. Explicit formulas expressing the material parameters in terms of scattering matrix coefficients are given for measurements at normal incidence. © 1993 John Wiley & Sons, Inc.
Near‐field pattern diffracted by a spherical cavity in a denser medium
Authors: And Jin‐Seob Kang , Ra Jung‐Woong
Published: July 2007

A copolarized electric field diffracted by a spherical cavity in a denser dielectric medium is analyzed in the forward near‐field region when the wavelength is comparable to one half the cavity radius. It is shown that double nulls and dips exist in the measurement plane transverse to the propagating direction of the incident field, and their dependences on the frequency, the distance of the measurement plane, and the measurement angles are analyzed. © 1993 John Wiley & Sons, Inc.
On the direct synthesis of high‐directivity tapered‐side‐lobe planar arrays with circular boundaries
Authors: Botha E. , McNamara D. A.
Published: July 2007

It is shown in this article how the generalized Villeneuve distribution can conveniently be used for the synthesis of high‐directivity low‐side‐lobe planar arrays with circular boundary shapes. © 1993 John Wiley & Sons, Inc.
Dual‐frequency microstrip antenna with inhomogeneously filled dielectric substrate
Authors: Lee Choon Sae , Nalbandian Vahakn , Schwering Felix
Published: July 2007

A novel dual‐frequency microstrip antenna is introduced. The antenna is relatively easy to design and fabricate. The operating frequency can vary over a wide range. © 1993 John Wiley & Sons, Inc.
Application of hadamard transform to fiber‐optic smart‐skin sensing
Authors: Yu Francis T. S. , Yin Shizhuo , Ruffin Paul B.
Published: July 2007

An array of optical fibers can be applied to smart‐skin sensing applications, which include stress monitoring, fatigue detection, temperature sensing, etc. Although a single light source can be used in a fiber array sensor, the input light power is divided by a sensing fiber array and each fiber may require a detector. Thus as the channel number of a fiber array increases, the number of detectors also increases and the signal intensity of each fiber channel decreases, which decreases the signal‐to‐noise ratio and increases the complexity and the cost of the system. In this article we will analyze the Hadamard transform to enhance the signal processing of the fiber array sensor. The apparent advantages are that only one detector is needed and the signal‐to‐noise ratio of the fiber array sensor can be improved by a factor of N/2, where N is the number of sensing fibers. Analysis for an array of 127 sensing fibers is illustrated, in which we have shown that the calculated results are in agreement with the analytical model. © 1993 John Wiley & Sons, Inc.
Design and realization of a low‐noise front end for a rdss mobile terminal
Authors: D'agostino Stefano , D'inzeo Guglielmo , Marietti Piero , Betti‐Berutto Andrea
Published: July 2007

A low‐cost high‐gain front‐end amplifier has been developed at 2.5‐GHz frequency for use in RDSS (radio determination satellite services) mobile terminals. The RDSS system allows an accurate positioning with the possibility of serving a large user population using the spread‐spectrum modulation. Such an amplifier, built on 0.8‐mm PTFE board, provides a low noise figure, a 31‐dB gain and good input and output matching on the 16‐MHz bandwidth allocation. All the results have been obtained using low‐cost commercially available devices. © 1993 John Wiley & Sons, Inc.
A perturbation approach to the analysis of index ellipsoid deformations in biaxial and uniaxial media
Authors: Faria J. A. Brandao
Published: July 2007

Under the disturbing influence of photoelastic, piezoelectric, or electrooptic effects, anisotropic media have their natural behavior modified, the modification being described by a change in both the dimensions and orientation of the index ellipsoid. A first‐order perturbation method useful for determining the perturbed index ellipsoid based on the unperturbed one is developed. Results concerning the new principal axes and principal refractive indices of the perturbed optical medium are presented. © 1993 John Wiley & Sons, Inc.
AN ULTRA‐LOW‐NOISE MILLIMETER‐WAVE OSCILLATOR USING A SAPPHIRE DISK RESONATOR AND HIGH‐TEMPERATURE SUPERCONDUCTOR GROUND PLANES
Authors: Negrete George V.
Published: July 2007

The first fully integrated HTS millimeter‐wave oscillator operating at 77 K with a phase noise improvement of 20 dB over conventional oscillators is reported. A loaded Q of 59,000 at 36.5 GHz obtained from a sapphire resonator shielded by HTS ground planes is almost 100 times greater than ceramic resonators. © 1993 John Wiley & Sons, Inc.
Analysis of a millimeter‐wave integrated beam‐forming network for quasioptical multibeam antennas
Authors: Bankov Sergey E. , Bugrova Tatiana I.
Published: July 2007

An integrated beam‐forming network analysis for multibeam antennas based on an array of dielectric slotted waveguides in millimeter waves is proposed. The advantages of such networks include low losses, high aperture efficiencies, and design flexibility in comparison with traditional quasitopical systems. A new technique for obtaining the main characteristics by solving eigenwave and diffraction problems of the basic structure of the proposed network has been developed. © 1993 John Wiley & Sons, Inc.
Design and realization of a reduced‐size microstrip 3‐dB rat‐race hybrid coupler
Authors: Brewster B. D. , Robertson I. D. , Gemikonakli O.
Published: July 2007

A reduced‐sized rat‐race coupler based on a meander line configuration, with bend equivalent phase length compensation, is presented. © 1993 John Wiley & Sons, Inc.
Polarization‐independent operation of reflective fiber ring resonators
Authors: Mouroulis Pantazis
Published: July 2007

The fringe shape stability of fiber ring resonators that incorporate an orthoconjugate reflector (OCR) is discussed. A resonator with a 90° polarization rotation and an OCR displays a stable fringe shape upon reflection, independent of the input polarization and of the loop birefringence. © 1993 John Wiley & Sons, Inc.
Axial propagation in general helicoidal bianisotropic media
Authors: Lakhtakia Akhlesh , Weiglhofer Werner S.
Published: July 2007

Helicoidal bianisotropic materials (HBMs) are rotationally inhomogeneous in one spatial direction. A simple procedure to derive exact solutions for axial propagation of electromagnetic waves in general HBMs is presented here. © 1993 John Wiley & Sons, Inc.
Electromagnetic scattering by a strip grating with nonplanar illumination
Authors: Gimeno B. , Marquina J. L. , Navasquillo J. , Pomer F.
Published: July 2007

An angular‐spectrum method combined with the Galerkin procedure has been used to evaluate the electromagnetic scattering of a beam radiated by an aperture antenna after being incident obliquely upon a strip grating. Integral expressions for the transmitted and reflected fields are obtained. The incident beam radiated by the antenna is diffracted in several beams corresponding to the propagative Floquet harmonics. An angular shift of the transmitted and reflected fundamental harmonic beams has been shown. Comparison between numerical and experimental results validates this method. © 1993 John Wiley & Sons, Inc.
High‐sensitivity optical sampling using an erbium‐doped fiber laser strobe
Authors: Schlager J. B. , Hale P. D. , Franzen D. L.
Published: July 2007

Optical pulses at a repetition frequency of 1 GHz from a gainswitched InGaAsP distributed‐feedback laser diode at 1.3 μm are optically sampled with compressed pulses from a mode‐locked erbium‐doped fiber laser amplifier. High signal‐to‐noise ratios down to 21‐μW average laser‐diode power with temporal resolutions close to the sampling pulse duration of 4 ps are achieved. The sampled waveform is displayed at a repetition rate of 3 Hz or higher to give a real‐time measurement.
Field singularities at the common tip of a number of concentric biisotropic cones
Authors: Olyslager Frank
Published: July 2007

In this contribution we present a general matrix formalism to determine the singular electromagnetic field behavior at the common tip of a number of concentric circular cones consisting of lossless biisotropic, perfect electric conducting or perfect magnetic conducting material. Three cases are studied in detail: a chiral salient and reentrant cone, two perfectly conducting cones, and a perfectly conducting cone balancing on a semiinfinite chiral space.
(FD)2‐TD and experimental comparison for a cylindrical cavity loaded with lossy dielectric
Authors: Hum P. J. , Leong M. S. , Kooi P. S. , Yeo T. S.
Published: July 2007

In this article, the frequency‐dependent finite‐difference time‐domain (FD)2‐TD technique is used to analyze a coaxial‐line excited cylindrical cavity loaded with an electrically lossy dielectric, modeled by a first‐order Debye expression. Results obtained for the reflected voltage in the coaxial line are Fourier transformed to yield the reflection coefficient Γ and input admittance at the coaxial aperture. Experimental measurements for Γ show good agreement with predicted (FD)2‐TD results.
Conductor‐backed and upper‐shielded coplanar waveguide with finite ground planes
Authors: Costamagna Eugenio , Fanni Alessandra
Published: July 2007

A variational procedure is proposed to accurately analyze the electrical quasi‐TEM parameters of coplanar waveguides, taking into account finite‐extent as well as semiinfinite lateral ground planes. The procedure leads to accurate calculations and allows comparison with results already presented for coplanar waveguides. Data for geometries incompletely analyzed in the technical literature are provided.
The variation of short‐gate‐length gaas mesfet intrinsic noise parameters with BIAS
Authors: Greaves S. D. , Unwin R. T.
Published: July 2007

The use of intrinsic noise parameters P, R, and C to describe the noise mechanisms present in short‐gate‐length GaAs MESFETs is well established. These parameters are, however, bias dependent, and as yet no analytic solution is available that can accurately predict this dependency. Here results are presented that show the evolution of these parameters with drain current for three practical devices.
Single‐mode four‐port optical fiber loop resonators using a nonplanar 3 × 3 fiber coupler
Authors: Ja Y. H. , Dai X.
Published: July 2007

This article presents the first experimental observation of the output resonance response of two single‐mode four‐port optical fiber loop resonators using a nonplanar 3 × 3 fiber coupler with a triangular cross section. It is found that, under a special condition of coupling strength kd = 2π/9, the output resonance responses of these two different types of fiber loop resonators are the same, and also identical to that of a same type of fiber ring resonator. The loop resonators may be used as two‐channel wavelength‐division multi/demultiplexers and optical switches.
A stable electric field integral equation approach for analyzing scattering from nonplanar wire meshes with arbitrarily small cell sizes
Authors: Michielssen E. , Whites K.
Published: July 2007

A simple and effective approach is presented for analyzing the plane‐wave scattering from nonplanar wire meshes. In contrast to both traditional integral equation solutions and homogenization techniques, which have a limited range of application in terms of the size of the unit cell, the present technique is applicable to structures with periodicities varying from a small fraction of the wavelength (e.g., 10−10λ0) up to several wavelengths. The technique is applied to the analysis of meshes consisting of straight wires as well as wire meshes containing helical elements.
Experimental reduction of phase‐noise influence for an optical CPFSK system with I.F. filtering
Authors: Jaouën Y. , Roudas I. , Gallion P.
Published: July 2007

Theoretical modeling and experimental analysis of the influence of i.f. filtering on performance of optical heterodyne CPFSK systems with differential detection in the presence of phase noise are compared. It is shown that for a bit rate of 1 Gbits/s with a modulation index of 1, i.f. filtering reduces phase noise influence, leading to a significant reduction of the bit‐error‐rate floor.
Cross‐polarization characteristics of rectangular microstrip patch antennas on a cylindrical surface
Authors: Ke Shyh‐Yeong , Wong Kin‐Lu
Published: July 2007

The cross‐polarization characteristics of a rectangular microstrip patch antenna mounted on a cylindrical surface are investigated by using the modal‐expansion theory. The case of the patch antenna excited at TM01 mode is treated. Numerical results showing the variations of the cross‐polarization level for various aspect ratios and different curvature radii are given. A great dependence of the cross‐polarization level on the curvature radius of the cylindrical microstrip patch antenna is observed. The effects of feed positions on the cross‐polarization characteristics are also analyzed.
Plane‐wave front: Novel representations
Authors: Ojeda‐Castañeda J. , Gómez Cristina M.
Published: July 2007

We report three novel formulas for representing any component of a plane‐wave front, in terms of known orthogonal functions, which describe the space variations as well as the angular variations. © 1994 John Wiley & Sons, Inc.
Influence of chirality parameter on the propagation characteristics of elliptical chirowaveguide
Authors: Cheng Dajun
Published: July 2007

The boundary value problem of an elliptical chirowaveguide is rigorously formulated by constructing the elliptical cylinder vector wave functions. Influence of chirality parameter both on the propagation axial constant and on the attenuation constant, are illustrated for the first several modes. © 1994 John Wiley & Sons, Inc.
Transient analysis of conducting half‐plane problem with noncausal scattering image
Authors: Nikoskinen K. I. , Lindell I. V. , Ermutlu M. E.
Published: July 2007

In the present article two‐dimensional transient scattering from a perfectly conducting half plane is studied. The excitation is an infinite impulsive line current parallel to edge of the conductor. Due to the symmetry of the problem the electromagnetic field everywhere is TM along the direction defined by the edge. The analysis presented in this article is based on a new time‐harmonic image solution found for the scattered field. The frequency‐domain image current giving the reflected and diffracted fields is an exact function that can be expressed in terms of simple trigonometric functions. It is dependent only on the coordinates and the amplitude of the source, but interestingly, it is independent of the used frequency. Thus, the corresponding time‐domain image is independent of time, which makes it noncausal. However, when integrating this image to compute the actual field, physical and causal results are obtained. © 1994 John Wiley & Sons, Inc.
Corrugated pyramidal horns with improved E‐plane radiation patterns
Authors: Narasimhan M. S. , Jayakumar Immanuel
Published: July 2007

The design and experimental studies on a pyramidal horn with corrugations and choke on the outer surface of the E‐plane walls excited in the TE10 mode with improved far‐field E‐plane patterns are reported in this Letter. © 1994 John Wiley & Sons, Inc.
Microstrip antenna with polarization switching
Authors: Dauguet Stéphane , Ongareau Eric , Wyrwinski Jacques
Published: July 2007

In this article the principle of an elementary printed antenna connected with an active hybrid coupler able to provide right‐ or left‐hand circular polarization is investigated. Dual‐gate MESFETs are used as phase shifters, and polarization switching is obtained by changing dc voltage applied to the control gate of each MESFET. Equal‐amplitude signals with identical phases can also be provided to generate linear polarization. Design and performance of a square patch with such polarization switching capability in S band is presented. © 1994 John Wiley & Sons, Inc.
Use of microstrip antenna technology in an angle diversity receiver for a 15‐GHz radio link
Authors: Tessereau S. , Zein G. El , Citerne J.
Published: July 2007

This Letter describes how the performance of a line‐of‐sight radio link can be improved by using an angular diversity receiver. The received antenna is a dual‐beam microstrip antenna realized with two linear arrays of 20 transverse printed dipoles, series fed by proximity coupling to a microstrip line. © 1994 John Wiley & Sons, Inc.
On the crucial role of impedance matching in chirolens design
Authors: Lakhtakla Akhiesh
Published: July 2007

It is shown that impedance matching delivers two specific benefits for chirolens design. First, there is no left‐handed ↔ right‐handed field conversion inside a nonhomogeneous chirolens with a spatially constant impedance. Second, when the chirolens is impedance matched to the surrounding free space, the incident, the scattered and the internally induced fields have the same handedness. In addition, the backscattered field of an impedance‐matched, radially non‐homogeneous, spherical chirolens is null in the far zone. © 1994 John Wiley & Sons, Inc.
Strain effects on refractive index and confinement factor of InxGa(1−x)As laser diodes
Authors: Ghafouri‐Shiraz H. , Tsuji S.
Published: July 2007

The effects of strain upon the bandgap energy, the refractive index, and the confinement factor of a SCH laser diode with InxGa(1−x)As as its active layer have been investigated. © 1994 John Wiley & Sons, Inc.
Scattering from an internal penetrable inhomogeneity of a dielectric slab waveguide
Authors: Yarovoy Alexander G.
Published: July 2007

A rigorous analysis of two‐dimensional scattering of a dielectric slab eigenmode from a penetrable cylinder is carried out by an integral equation method. A new procedure for reduction of an initial integral equation system to a well‐conditioned matrix equation is developed. Numerical results are presented for cylinders with different cross‐section shapes. A physical explanation of the revealed effects is proposed. © 1994 John Wiley & Sons, Inc.
Spectral‐domain decoupling method of electromagnetic waves propagating and radiating in bianisotropic gyroelectromagnetic chiral media
Authors: Wenyan Yin , Pao Li , Wei Wan
Published: July 2007

In this article a spectral‐domain decoupling method of electromagnetic waves propagating and radiating of sources in bianisotropic gyroelectromagnetic chiral media is presented, and the general transmission‐line‐like equations for the description of field quantities (IE‐, VE, VM, IM) are obtained using the technique of matrix transformation, which has been developed by Tsalamengas. As a practical application, the propagation behavior of electromagnetic waves in multilayered bianisotropic gyroelectromagnetic parallel‐plate chirowaveguides is investigated, and it is shown that in such a nonreciprocal chirowaveguide, propagating modes are always hybrid (EH and HE). Especially, the dyadic Green's function of sources in a grounded bianisotropic gyroelectromagnetic chiral superstrate‐substrate structure is derived, and it can be directly used to analyze the radiation characteristics of gyroelectromagnetic chirostrip antennas. © 1994 John Wiley & Sons, Inc.
Analysis of spherical annularring microstrip structures with an air gap
Authors: Chen Horng‐Dean , Wong Kin‐Lu
Published: July 2007

The spherical annular‐ring microstrip structure with an air gap is studied rigorously by using a full‐wave analysis and a momentmethod calculation. This study includes the analysis of the resonant frequencies and bandwidths of the microstrip structure for antenna applications. Results show that the bandwidth increases due to the existence of an air gap. This increase in bandwidth is also found to be more significant for the annular‐ring patch with smaller inner radius. © 1994 John Wiley & Sons, Inc.
Acousto‐optic star couplers for routing and broadcasting in local area networks
Authors: Helaly Anwar M. , Abushagur Mustafa A. G.
Published: July 2007

Acousto‐optic deflectors are introduced to be used as star couplers that perform broadcasting and routing in local area networks. Configurations for both single‐wavelength and multiwavelength broadcast‐and‐select networks are proposed. A routing network in which both the input and output ports are wavelength tunable is also shown. Acousto‐optic devices provide these networks with the advantage of low insertion loss, simplicity, and compactness, because one device can handle a large number of ports. Analysis for these networks is presented and computed simulation results are shown. The proposed routing network is not limited to the use of acousto‐optic deflectors, because conventional blazed diffraction gratings can be used. © 1994 John Wiley & Sons, Inc.
The effect of noise in the data on the Cauchy method
Authors: Adve R. , Sarkar T.
Published: July 2007

In this article the effect of noise in the data on the Cauchy method is discussed. The noise is assumed to be zero mean and Gaussian. The resulting random variable is a ratio of two Gaussians. The theoretical probability density function is verified by numerical simulation. © 1994 John Wiley & Sons, Inc.
Novel characteristics of radiation patterns of a pseudochiral point‐source antenna
Authors: Toscano Alessandro , Vegni Lucio
Published: July 2007

We present certain novel characteristics of the radiation pattern of a pseudochiral point‐source antenna, which consists of an elemental antenna embedded in a grounded pseudochiral substrate in the presence of an isotropic half‐space. The pseudochiral Ω medium is a new synthetic bianisotropic material, recently introduced by Engheta and Saadoun [1]. The expression of the electric field radiated by a pseudochiral grounded slab is given in a form such as to simplify the extraction of noticeable information to be used during the project, about the influence of frequency, constitutive parameters, thickness of the slab, and position of the electric source. © 1994 John Wiley & Sons, Inc.
Theoretical analysis of an open‐ended coaxial probe on a cylinder of finite thickness
Authors: de Langhe P. , Martens L. , de Zutter D.
Published: July 2007

The admittance of an open‐ended coaxial probe on a dielectric cylinder of finite thickness surrounded by a cylindrical outer layer of equal thickness but with a different dielectric constant is calculated analytically. The cylinder and the surrounding material are backed by a metal plate. The theoretical results indicate up to which frequency the measured value of the dielectric constant of the cylindrical sample remains independent of its lateral dimensions. © 1994 John Wiley & Sons, Inc.
Optical beam steering using a liquid‐crystal television panel
Authors: Tanone Aris , Zhang Z. , Uang C.‐M. , Yu Francis T. S. , Gregory Don A.
Published: July 2007

A blazed grating can be generated using a programmable liquid‐crystal television (LCTV) panel. Despite the effects of phase mismatch, phase quantization, and pixel addressing of the panel, optical beam steering is possible, particularly for small angle deflection applications. © 1994 John Wiley & Sons, Inc.
Temperature distribution in biological media by microwave radiometry: Preliminary results
Authors: Bregni S. , Caorsi S. , Gragnani G. L.
Published: July 2007

Multispectral microwave radiometry for temperature reconstruction inside biological media is considered. Radiometric data on simulated living tissues have been obtained with a multifrequency radiometer in the frequency range 1.5–3.5 GHz. Temperature retrieval has been modeled as the solution of a first‐kind integral equation, based on the theory of radiative transfer. An example of temperature retrieval is reported. Results compare favorably with experimental measures. © 1994 John Wiley & Sons, Inc.
Optical low‐coherence reflectometry (OLCR) for dimensional monitoring of sheet‐grown silicon
Authors: Lawson C. M. , Michael R. R.
Published: July 2007

We report cross‐sectional thickness and flatness measurements for edge‐defined film‐fed growth (EFG) solar silicon using optical low coherence reflectometry (OLCR). The measurement accuracy is ±1.5 μm with the sensor head positioned 1 cm away from the EFG silicon under test. © 1994 John Wiley & Sons, Inc.
Analysis of probe‐fed spherical‐circular microstrip antennas using cavity‐model theory
Authors: Chen Hong‐Twu , Wong Kin‐Lu
Published: July 2007

This article presents a cavity‐model analysis of spherical‐circular microstrip antennas. In this study, expressions for the input impedance and far‐zone radiated fields are derived and given. Numerical results of the input impedance and radiation patterns for the antenna excited at the TM11 mode are presented, and are compared with those obtained by the generalized transmission line model and the full‐wave approach to discuss the applicability of the cavity‐model theory for the analysis of spherical microstrip antennas. © 1994 John Wiley & Sons, Inc.
Power distributed amplifier with input‐output combiners
Authors: D'Agostino Stefano , Paoloni Claudio
Published: July 2007

A novel distributed amplifier topology is proposed to increase the power performance and the gain. In comparison with the conventional configuration, a considerable advantage is obtained by introducing Lange couplers at the input and output ports of the amplifier. Design examples are discussed to confirm the validity and the effectiveness of the proposed topology. © 1994 John Wiley & Sons, Inc.
Variational formulation of electromagnetic boundaryvalue problems involving anisotropic media
Authors: Jin Jianming , Chew Weng Cho
Published: July 2007

A variational formulation is presented for electromagnetic boundaryvalue problems involving anisotropic media. Specific functionals are given, along with a discussion of the property of the resulting numerical system, for general problems involving general anisotropic media, for lossy problems involving anisotropic media having symmetric permittivity and permeability, and for lossless problems involving anisotropic media having Hermitian permittivity and permeability. © 1994 John Wiley & Sons, Inc.
Time‐domain modeling of the impedance boundary condition for an oblique incident perpendicular‐polarization plane wave
Authors: Wang Bing‐Zhong , Zhou Na
Published: July 2007

In this article, the frequency‐domain impedance boundary condition used for a thin layer coating over perfect conductors is transformed to a time‐domain impedance boundary condition (TDIBC) for the case of ablique incident perpendicular‐polarization plane wave, resulting in a partial differential equation in space and time. Discretization of the TDIBC to effeciently handle the thin layer coating is presented in the context of the time‐domain finite‐difference (TDFD) technique. The TDFD solutions using our TDIBC are in good agreement with the analytical results. © 1994 John Wiley & Sons, Inc.
How does threshold detection limit atmospheric turbulence in number state optical channels?
Authors: Fares Doaa A.
Published: July 2007

In this article, analysis for the recently considered photon number state optical channel [1–3] is presented. Under atmospheric turbulence conditions, the channel performance is highly affected and deteriorated. Therefore, coding‐in particular Reed‐Solomon block codes [4]‐becomes a must. In this presentation, the optimal threshold performance conditions are calculated and are shown to prove their strong control on the channel turbulence, yielding reliable communication. Other channel measures such as channel transparency, information efficiency, and transmission rate are investigated. © 1994 John Wiley & Sons, Inc.
Slow‐wave analysis on double‐layered substrates
Authors: Hindy Moataza A.
Published: July 2007

A full‐wave analysis of a slow‐wave microstrip transmission line on a ferromagnetic semiconductor with an insulator is presented. The spectral‐domain method with a sampling theorem is used. A new current distribution is applied. The slow‐wave factor and the characteristic impedance are calculated for different material conductivities σ with variable applied dc magnetization. © 1994 John Wiley & Sons, Inc.
Full‐wave analysis using a tangential vector finite‐element formulation of arbitrary cross‐section transmission lines for millimeter and microwave applications
Authors: Helal M. , Legier J. F. , Pribetich P. , Kennis P.
Published: July 2007

A tangential vector finite‐element formulation is implemented to deal with arbitrary cross section and metallic strip shape. Classical planar transmission lines as well as nonconventional cross‐section waveguides such as the new microshield line are treated. Effects on propagation characteristics for these lines are studied when the metallization shape is approximated by a lossy trapezoid area. © 1994 John Wiley & Sons, Inc.
An efficient two‐dimensional discrete fourier transform analysis of periodic pixels of TFT/LCDs
Authors: Lin Jin‐Shin , Lee Wei‐Yu
Published: July 2007

An efficient 2D DFT method is proposed to investigate the characteristics of periodic pixels of TFT/LCDs. The electric field distributions under the pixel electrode are illustrated in three dimensions for the first time. A two‐capacitor model derived based on the coupling effect is also presented. Means of reducing capacitance to obtain the high‐density pixels of TFT / LCDs are suggested. Numerical results are given to establish useful guidelines for design. © 1994 John Wiley & Sons, Inc.
Quasicomplex modes of boxed coplanar lines on lossy dielectric substrate for millimeter‐wave applications
Authors: Delplanque Y. , Huret F. , Kennis P. , Pribetich P.
Published: July 2007

In this Letter, we propose to show the existence of quasicomplex modes of boxed coplanar lines laid on a lossy dielectric substrate for millimeter‐wave applications, using the method of lines with non‐equidistant discretization. These quasicomplex modes are defined by studying the behavior of the two complex solutions of the propagation problem of the classical lossless boxed coplanar line versus the losses of dielectric substrate. © 1994 John Wiley & Sons, Inc.
Spectral electric green's dyad for a grounded bianisotropic slab fed by a three‐dimensional point source
Authors: Toscano Alessandro , Vegni Lucio
Published: July 2007

The subject of this article is the analysis of planar stratified structures with a general bianisotropic grounded slab fed by a threedimensional electric point source. The electromagnetic problem is solved in terms of the spectral electric Green's dyad. The elements of the first and third column of the spectral Green's dyad are directly derived from the transmission line equations satisfied by the electromagnetic field in the two‐dimensional Fourier domain. The reaction theorem and the Parseval theorem are then applied to the spectral electromagnetic field, and the elements of the second column of the spectral Green's dyad are provided. Finally, as an application of the theory, we present the expression of the Gyy term when the bianisotropic grounded slab is a pseudochiral one. © 1994 John Wiley & Sons, Inc.
Introduction of radiating losses in the time‐domain transmission‐line method
Authors: Relneix A. , Jecko B.
Published: July 2007

The classical transmission‐line method allows the study of the propagation of a TEM mode along a line. Then, if it is possible to consider nonlocalized losses on a line, the radiation phenomena are not taken into account. In this article, we propose a modification of the transmission‐line method to include radiation phenomena due to discontinuities of impedance or nonrectilinear lines. © 1994 John Wiley & Sons, Inc.
Broadwall slot coupling into butt‐ended waveguide
Authors: Rengarajan Sembiam R. , Elliott Robert S.
Published: July 2007

We present an analysis of a slot cut in a broadwall of a rectangular waveguide, coupling into a semiinfinite rectangular waveguide capped by a conducting transverse plate containing the slot. Slots coupling into butt‐ended waveguides are employed in test fixtures in slot array applications. Pertinent integral equations for the slot‐aperture electric field are solved by the method of moments, and scattering characteristics of slot couplers for butt‐ended guides are deduced. Numerical results indicate limitations of these couplers for applications involving reduced‐height guides. © 1994 John Wiley & Sons, Inc.
Sensitivity penalty in optically preamplified ppm with slot timing jitter impairment
Authors: Elmirghani Jaafar M. H. , Cryan Robert A.
Published: July 2007

The impact of timing jitter on PPM utilizing an erbium‐doped fiber amplifier (EDFA) front end is considered. In the absence of jitter the sensitivity calculations indicate that EDFA PPM offers 7.9–dB sensitivity improvement over EDFA PCM at 622 Mbit/s and λ = 1.53 μm. An original analysis and results are presented for the impact of the extracted slot clock timing jitter on EDFA PPM sensitivity. The jitter sensitivity penalty is shown to vary between 0.15 and 1.9 dB for the range of parameters considered. The selection of the slot phase‐lock loop (PLL) bandwidth that minimizes the jitter penalty is investigated. © 1994 John Wiley & Sons, Inc.
Anisotropic intrasignal coupling in photorefractive linbo3
Authors: Zhao Dazun , Zhou Hanying , Zhao Feng , Yu Francis T. S.
Published: July 2007

Intrasignaling coupling in a LiNbO3 photorefractive crystal is studied. It is shown that the anisotropy nature of the effective electrooptic coefficient of this crystal results in an orientation‐dependent intrasignal coupling. Analytical solutions for one‐dimensional intrasignal coupling are derived for a‐axis and b‐axis orientations, which enables us to estimate the maximum beam field angle and the maximum crystal thickness for a given intensity distortion due to the coupling. The results are thus illustrative to applications of this crystal in areas such as holographic data storage, interconnection, spatial mode conversion, et cetera. © 1994 John Wiley & Sons, Inc.
The two‐point target technique for free‐space permittivity measurements of lossy dielectrics
Authors: Yin Hongcheng , Zhang Wenxun , Xiao Zhihe , Huang Peikang
Published: July 2007

A new technique for permittivity measurements of lossy dielectrics is presented. It is based on the measurements of backscattering cross section and linear deviation (angular glint) of a two‐point target, consisting of a conducting sphere with a dielectric one or a conducting one coated by the material under test. Because the linear deviation is proportional to the derivative of phase versus aspect angle, this technique overcomes the difficulty encountered in accurately measuring the phase in free space. Moreover, the choice of spherical targets, makes positioning less critical. The effectiveness of such a technique is verified by numerical simulations and measurements. © 1994 John Wiley & Sons, Inc.
A full‐wave analysis of tuning and coupling posts in dual‐mode circular waveguide filters
Authors: Montejo‐Garai J. , Valor L. , Garcia J. , Zapata J.
Published: July 2007

A generalized scattering matrix of a circular waveguide with several posts inserted has been derived. The number of posts can be selected from one to eight and placed at 45° angles on the waveguide perimeter. Computation is based on an automated finite‐element‐mode‐matching method that only requires the main geometrical dimensions as input data. A structure containing three screws inserted in a dualmode cylindrical cavity, iris coupled to input and output rectangular waveguides, has been analyzed. Excellent agreement with measured data has been found. © 1994 John Wiley & Sons, Inc.
Full‐wave analysis of input impedance and patch current distribution of spherical annular‐ring microstrip antennas excited by a probe feed
Authors: Chen Horng‐Dean , Wong Kin‐Lu
Published: July 2007

This article presents a full‐wave analysis of probe‐fed spherical annular‐ring microstrip antennas. The formulation of the input impedance is given, and numerical results of the input impedance and the surface current distribution on the annular‐ring patch excited at TM12 mode are calculated and analyzed. It is found that several other modes are usually excited with the excitation of the TM12 mode. The corresponding surface current distributions for these degenerate modes are presented and discussed. © 1994 John Wiley & Sons, Inc.
Modal analysis of optical waveguides using prony's method and bpm
Authors: Chamorro‐Posada Pedro , Gómez‐Alcalá Rafael , Javier Fraile‐Peláez F.
Published: July 2007

We present the application of Prony's method to the problem of computing the complex propagation constants of guided optical modes from data obtained with the beam propagation method (BPM). Prony's method provides accurate results for the complex propagation constants and also gives the amount of power carried by each of these modes as well as their relative phases, for both absorbing and nonabsorbing waveguides. © 1994 John Wiley & Sons, Inc.
Short‐circuit photocurrent‐controlled microwave p‐i‐n diode switch
Authors: Gevorgian S. S.
Published: July 2007

It is shown that in microwave surface oriented p‐i‐n diodes enough short circuited photocurrents can be excited to make them effectively forward biased. © 1994 John Wiley & Sons, Inc.
An extended fukui‐like formula for the minimum‐noise figure of microwave fets
Authors: Bonani Fabrizio , Ghione Giovanni
Published: July 2007

The article presents an extension of the well‐known Fukui formula for the minimum noise figure of microwave FETs, based on a complete small‐signal equivalent circuit including parasitic elements, the feedback capacitance Cgd, and the output admittance (Gds and Cds). We show that the simplified circuit neglecting all of the above elements, on which most Fukui‐like expressions are based, overestimates NFmin, mainly because Cgd is discarded; moreover, the linear approximation of NFmin(f) from the complete circuit is more accurate than the quadratic one, while parasitic inductances affect the terms of the series expansion of NFmin in powers of f from the third order only. © 1994 John Wiley & Sons, Inc.
The effects of magnetic biasing fields on the far‐field distributions of source on composite ferrite media
Authors: Wenyan Yin , Wei Wan , Wenbing Wang
Published: July 2007

In this article the radiation characteristics of a dipole antenna on grounded composite ferrite structures are studied using the generalized spectral‐domain–exponential‐matrix technique. Numerical results are presented to show the effects of internal dc magnetic bias fields, operating frequency, geometrical sizes, and losses of substrates on the radiation pattern and scanning characteristics of dipoie antenna. The figures show that it is possible to obtain an optimum radiation pattern by choosing suitable constitutive and geometrical parameters of ferrite materials. © 1994 John Wiley & Sons, Inc.
Resonant frequency of a slot‐coupled cylindrical‐rectangular microstrip structure
Authors: Wong Kin‐Lu , Chen Yeong‐Chin
Published: July 2007

The resonance problem of a slot‐coupled cylindrical‐rectangular microstrip structure is investigated by using the exact derived Green's functions for the structure in a spectral‐domain moment‐method solution. The resonant frequencies of the slot‐coupled microstrip structure with various curvature radii are calculated and presented. It is observed that the resonant frequency is affected by both the slot length and the curvature radius. © 1994 John Wiley & Sons, Inc.
Analysis of microstrip step discontinuities in mics printed on anisotropic substrates using the method of moments
Authors: Cain Jeffrey , Beker Benjamin
Published: July 2007

This article presents a full‐wave analysis of microstrip step discontinuities in shielded MICs that are printed on anisotropic substrates, characterized by both permittivity and permeability tensors. The numerical procedure utilizes the method of moments with rooftop basis functions for current expansion and testing. Although the work presented herein emphasizes step junctions, more complicated microstrip discontinuities can easily be realized as well. Numerical results show good agreement with independent data for biaxial substrates. © 1994 John Wiley & Sons, Inc.