bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new predistortion scheme for reduction of intermodulation distortion in optical cable TV SCM receivers
Authors: Domingues Paulo Grilo , Pedro José Carlos 
Published: July 2007

AbstractA new predistortion scheme for cancellation of second‐order intermodulation (IMD) products in broadband optical subcarrier multiplexing (SCM) receivers is presented. This method relies on the phase inversion provided by a common‐source FET amplifier, which allows the compensation of the even‐order distortion products, generated in a cascade of two such stages. Also, it is shown how a careful selection of the FET's bias point can be a valuable tool for controlling the remaining odd‐order IMD components. An optical‐receiver prototype based on these ideas is evaluated. © 1994 John Wiley & Sons, Inc.
On the modeling of a cavity enclosed broadband circular patch antenna for L‐band land mobile satellite communications
Authors: Karmakar N. C. , Bialkowski M. E. 
Published: July 2007

AbstractAn RLC circuit is used to model the probe‐fed cavity enclosed circular disc antenna. An electromagnetic coupling feed mechanism and series LC compensation are applied to improve the operational bandwidth of this antenna. © 1994 John Wiley & Sons, Inc.
Integrated waveguide‐photodetector coupling by modal fitting
Authors: Chamorro‐Posada Pedro , Fralle‐Peláez F. Javier 
Published: July 2007

AbstractWe present a novel method for the design of high‐coupling integrated waveguide photodetectors. This method is based on choosing the photodetector absorbing‐layer thickness such that the modal profile of the field in the waveguide fits that of one mode of the photodetector. Our beam‐propagation method simulations of the devices so designed show that the quantum efficiency obtained with this approach is comparable to those using vertical impedance‐matching layers, but with simpler structures. © 1994 John Wiley & Sons, Inc.
Hybrid finite‐element analysis of scattering and radiation by a class of waveguide‐fed structures
Authors: Jin Jianming , Lee Shung‐Wu 
Published: July 2007

AbstractA hybrid finite‐element method is presented for analysis of scattering and radiation of a class of waveguide‐fed structures that are characterized by a waveguide region, an exterior region, and a transition region. The proposed method formulates the exterior field in terms of boundary integrals and the field in the transition region using the finite‐element method. The effect of the waveguide field is incorporated through an exact absorbing boundary condition, which includes all waveguide modes. Numerical results are given to demonstrate the accuracy and capability of the method. © 1994 John Wiley & Sons, Inc.
S‐matrix definition for microwave‐optical transducers
Authors: Stockbroeckx Benoit , Dellisse Philippe , Vorst André Vander 
Published: July 2007

AbstractThere is no rigorous definition of the S matrix for the electro‐optic components. This article proposes such a characterization, based on usual microwave theory. Transmission‐line models, reflection coefficient, and available gain definitions are also proposed. © 1994 John Wiley & Sons, Inc.
The dispersion curves of partly loaded circular chirowaveguides
Authors: Chen Ling , Zhang Ming , Zhang Wen Xun 
Published: July 2007

AbstractThe dispersion characteristics of partly loaded circular chirowaveguides are analyzed. The cross section of the waveguide is divided into two coaxial regions loaded with chiral and achiral materials, respectively. The dispersion curves are carried out for the cases of chiral rod or ring loading; the influences of the ratio of radii are discussed as well. © 1994 John Wiley & Sons, Inc.
Optimization of the total bandwidth of the modulator/deflector of an acousto‐optical spectrum analyzer used in radio‐astronomy applications
Authors: Garde M. J. , Sebastian J. L. , Benito D. , Aramburu C. 
Published: July 2007

AbstractThe acoustic and the Bragg bandwidths can be optimized by using a modified mass electrode for the TeO2crystal and a quasitangent interaction instead of the classical tangent interaction, respectively. These optimizations lead to a 40% increase of the total bandwidth of the modulator/deflector. Therefore, a higher value of the ‐3‐dB‐bandwidth‐spectral‐resolution ratio N is obtained. This allows us to study both wider spectral lines (up to 90 MHz) and lines separated no more than 90 MHz, which means sauing costly real observation time. © 1994 John Wiley & Sons, Inc.
Design proposal of an asymmetric three‐phase‐shift distributed feedback laser diode
Authors: Ong B. S. , Ghafouri‐Shiraz H. , Lo B. S. K. 
Published: July 2007

AbstractThe effects of using asymmetric phase shifts along the corrugation of a three‐phase‐shift (3PS) distributed feedback (DFB) laser diode (LD) have been investigated. Based on the transfer matrix method (TMM), design contours showing variations of the threshold gain margin Δα and the internal field uniformity F are presented with respect to the phase‐shift values and the phase‐shift positions (PSP). It has been found that in order to minimize the effects of spatial hole burning (SHB) and hence maintain a stable single longitudinal mode (SLM) oscillation, the following criteria should be used: (i) center phase shift, θ3 = π/6, (ii) 0.15 < PSP < 0.35, and (iii) 2π/9 < θi, (i = 2, 4) < 4π/9. © 1994 John Wiley & Sons, Inc.
Analysis of the class E amplifier by an alternor technique
Authors: Li Chi‐Hung , Yam Yu‐On 
Published: July 2007

AbstractAn altemor technique is introduced for the fast simulation of the output performance of the Class E amplifier. The transistor used in the class E amplifier is modeled as a two‐port network by the altemor technique. A six‐order matrix equation of the amplifier is obtained according to this model and the simple cut‐set and loop theory. The output performance of the amplifier can thus be simulated by solving this matrix equation. © 1994 John Wiley & Sons, Inc.
Offset tripatch microstrip antenna
Authors: Tong K. F. , Luk K. M. 
Published: July 2007

AbstractAperture‐coupled offset dual‐patch antenna with a SWR bandwidth of 38% has been demonstrated recently [1]. The possibility of further improvement in bandwidth by adding one more parasitic patch is investigated experimentally. It is found that a SWR bandwidth of 48% can be achieved but the gain varies significantly over the passband. © 1994 John Wiley & Sons, Inc.
A catheter antenna for percutaneous microwave therapy
Authors: Lin James C. , Wang Yu‐Jin 
Published: July 2007

AbstractA flexible catheter antenna with a curved tip is described for transcutaneous microwave treatment of cardiac tachyarrhythmias. In tissue‐equivalent phantom modeling materials, the enlarged inner conductor cap and coaxial choke design yields SAR distributions that accentuate heating of tissue toward the distal end of the catheter antenna. The power reflection coefficient is less than 4%.
An exact method for simulating boundary conditions for mesh termination in finite‐difference techniques
Authors: Djordjevic A. R. , Sarkar T. K. , Roy T. , Rao S. M. , Salazar M. 
Published: July 2007

AbstractFinite‐difference methods are standard techniques for solving the differential form of Maxwell's equations. In spite of many advantages, a drawback of the technique is how to implement an absorbing boundary condition in an essentially exact fashion. In this article an absorbing boundary condition is proposed based on the Green's functions arising in integral equations. The radiation condition in this approach is built up iteratively as the solution progresses utilizing the Green's function. In the proposed method only two layers of meshes outside the boundary may be sufficient. Examples have been presented for the electrostatic case to illustrate the accuracy and convergence of this new technique.
Multidimensional microwave imaging
Authors: Odendaal Johann W. 
Published: July 2007

AbstractThe high computational load associated with multidimensional high‐resolution algorithms is overcome by using only 1D LP techniques. The 3D backscattered field is approximated by three 1D AR models that are solved in succession for the down‐range, horizontal cross‐range, and vertical cross‐range positions of the scattering centers of a target.
Calculation of attenuation and phase shift in a rain medium using the dielectric mixture model with deformed raindrops
Authors: Yeo T. S. , Gao M. Z. , Kooi P. S. , Leong M. S. 
Published: July 2007

AbstractA modified approach for computing the effective permittivity of a dielectric mixture has been applied to obtain the attenuation and phase shift of both horizontally and vertically polarized electromagnetic waves in the rain medium. This approach takes into consideration the distributions in raindrop sizes, shapes, and depolarization factors. The computed results agree well with those obtained from the more complicated Mie scattering theory. The differential attenuation and phase shift between horizontally and vertically polarized waves are also obtained using the proposed model and their calculated values compare favorably with available published results by Oguchi (oblate spheroid rain droplets) and Pruppacher and Pitter (deformed rain droplets).
|J1(U)/U| distribution synthesis in circular ring array
Authors: Yu Cheng‐Cheh 
Published: July 2007

AbstractThis article proposes a unified method for |J1(u)/u| distribution synthesis in an equispaced circular ring array. The |J1(u)/u| distribution has much lower side lobes than that in the J0(u) distribution. The simulation results using the proposed method have shown this possibility. Hence, the |J1(u)/u| distribution can be utilized to control the side‐lobe levels in most applications.
On the application of a neural network in the design of cascaded gratings
Authors: Christodoulou C. G. , Huang J. , Georgiopoulos M. , Liou J. J. 
Published: July 2007

AbstractThis article presents a study of the ARTMAP neural network in designing cascaded gratings. A neural network can be trained to keep changing the dimensions of the metallic strips, their distance of separation, their width, the number of layers required in a multilayer structure, and the angle of wave incidence until the frequency response of the structure matches the desired one. In the past, the back‐propagation (back‐prop) learning algorithm was used in conjunction with an inversion algorithm for the design of frequency‐selective surfaces. Unfortunately, both the back‐prop algorithm and the inversion procedure are slow to converge. In this work the Fuzzy ARTMAP neural network is utilized. The fuzzy ARTMAP is faster to train than the back‐prop, and it does not require an inversion algorithm. Several results (frequency responses) from cascaded gratings for various angles of wave incidence, layer separation, width strips, and interstrip separation are presented and discussed. © 1995 John Wiley & Sons. Inc.
A 4‐GHz microstrip BPSK varactor‐tunedp‐i‐ndiode modulator
Authors: Geelen B. D. Brewster 
Published: July 2007

AbstractA suppressed carrier modulator with compensation to individual constellation points, based on a reflective switching 180° hybrid coupler configuration, is described. The design minimizes modulated signal parasitic phase and amplitude errors by tuning opposing signal states in the presence of physical fabrication dissimilarities. © 1995 John Wiley & Sons. Inc.
High‐yield 3.55‐GHz repetition rate monolithic mode‐locked semiconductor lasers
Authors: Helkey Roger J. , Zou Wei‐Xiong , Mar Alan , Young D. Bruce , Bowers John E. 
Published: July 2007

AbstractA monolithic model‐locked semiconductor laser was demonstrated with a repetition rate of 3.55 GHz and a pulse width of 14.6 ps. The relative timing jitter was 490 fs, low enough for multiple‐source time‐division multiplexing. A single six‐element array was fabricated with a 6.7‐cm total waveguide length. Device yields for monolithic devices are analyzed. © 1995 John Wiley & Sons, Inc.
A numerical absorbing boundary condition for quasi‐TEM analysis of microwave transmission lines using the finite‐element method
Authors: Pantic‐Tanner Zorica , Mavronikolas George , Mittra Raj 
Published: July 2007

AbstractThis article presents a new numerical absorbing boundary condition useful for quasi‐TEM analysis of open‐type microwave transmission lines employing the finite‐element method (FEM). The standard FEM equations are used for the inner nodes of the mesh, and mesh truncation is achieved by imposing linear relationships for the nodes on the outer boundary and their neighbors, which are derived from the appropriate Green's functions. This approach greatly reduces the mesh size, while preserving the sparsity of the FEM equations. Higher‐order approximations of the absorbing boundary condition are derived through the use of higher‐order finite elements. © 1995 John Wiley & Sons, Inc.
Application of the complementary operator method to the finite‐difference‐time‐domain solution of the three‐dimensional radiation problem
Authors: Ramahi Omar M. 
Published: July 2007

AbstractA highly accurate absorbing boundary operation has been developed to efficiently and accurately truncate the computational domain when using the finite‐difference‐time‐domain method. Referred to as the complementary operators method (COM), this technique consists of averaging the solutions of two independent boundary operators that are complementary to each other. Because of its independence of the wave number kx, the boundary operation can significantly reduce artificial reflections arising from obliquely incident traveling waves as well as evanescent waves. © 1995 John Wiley & Sons, Inc.
Mesh truncation in the finite‐element frequency‐domain method with a perfectly matched layer (PML) applied in conjunction with analytic and numerical absorbing boundary conditions
Authors: Pekel Ü. , Mittra R. 
Published: July 2007

AbstractThe perfectly matched layer (PML) concept, introduced by Berenger with the aim of synthesizing an absorbing boundary condition (ABC) for the finite‐difference‐time domain (FDTD) method, is modified and extended to finite‐element frequency‐domain (FEFD) applications. The governing equations that characterize this approach do not require the splitting of the field components of interest, nor do they involve negative conductivity parameters. The PML‐type medium is employed together with analytic and numerical ABCs as its termination to obtain an improved boundary condition for the FEFD method at a limited increase in computational cost. © 1995 John Wiley & Sons, Inc.
New technique for the design of a two‐layered wave absorber for cylindrical objects
Authors: Hashimoto Osamu , Motoyoshi Souichiro , Altman Zwi 
Published: July 2007

AbstractA technique for the design of a two‐layered wave absorber for cylindrical objects using an expanded polystyrene mixed carbon coating is presented. The concentrations of the mixed carbon in the two absorbing layers and their thicknesses are determined from the design specifications. Design charts for the wave absorber for TE and TM polarizations are calculated, and their wideband absorbing characteristics are presented. © 1995 John Wiley & Sons, Inc.
Input impedance of dielectric resonator antennas top loaded with high permittivity and conducting disks
Authors: Junker Gregory P. , Glisson Allen W. , Kishk Ahmed A. 
Published: July 2007

AbstractA numerical investigation verified by measurements is performed to study the difference between loading the dielectric resonator antenna with conducting or high‐dielectric‐constant disks. The basic objectives of this study are to suggest ways to eliminate losses by replacing conducting antenna parts with dielectric parts, to design antennas with dual resonances, and to broaden impedance bandwidth. Input impedances are computed and measured when the ground‐plane‐backed dielectric resonator is excited by a coaxial probe. Excellent agreement is obtained between the numerical and the measured input impedances. © 1995 John Wiley & Sons, Inc.
A novel microwave periodic structure — the ladder microstrip line
Authors: Hong J. S. , Lancaster M. J. 
Published: July 2007

AbstractA novel microwave periodic structure—the ladder microstrip line—is proposed. A preliminary investigation has shown that the novel transmission line has a lower phase velocity as compared with the conventional microstrip line even when they occupy the exact same surface area and have the same outline contour. This makes it attractive for monolithic microwave integrated circuits (MMIC) and microwave superconductive circuits, where size reduction is of primary importance. © 1995 John Wiley & Sons, Inc.
Numerical dispersion in the finite‐element method using triangular edge elements
Authors: Warren Gregory S. , Scott Waymond R. 
Published: July 2007

AbstractThe discretization inherent in the finite‐element method results in the numerical dispersion of a propagating wave. The numerical dispersion of a time‐harmonic plane wave propagating through an infinite, two‐dimensional, finite‐element mesh composed of uniform triangular edge elements is investigated in this work. The effects on the numerical dispersion of the propagation direction of the wave, the electrical size of the elements, and the mesh geometry are investigated. The dispersion for the hexagonal mesh geometry is shown to be much smaller and to converge at a quicker rate than the other meshes. The dispersion analysis is validated by numerical examples. © 1995 John Wiley & Sons, Inc.
Decomposition of the scattering by a finite linear array into periodic and edge components
Authors: Denison Douglas R. , Scharstein Robert W. 
Published: July 2007

AbstractThe field scattered by each element in a finite array is decomposed into the contribution of the infinite or periodic array, a component due to the presence of the left edge of the array, and a component due to the right edge of the array. The scattered field due to either array edge is derived from a separate analysis of the appropriate semiinfinite array and is interpreted in terms of a decaying wave that is launched from the array end. © 1995 John Wiley & Sons, Inc.
Large‐signal modulation characteristics of laser diodes with weak coherent optical feedback
Authors: Wang J. , Haldar M. K. , Mendis F. V. C. 
Published: July 2007

AbstractIt is shown that although inadvertent weak coherent optical feedback can adversely affect the small‐signal response of a directly modulated semiconductor laser, its effect on large‐signal modulation response can be small. The result is of significance of the response of directly modulated lasers in subcarrier multiplexed systems. © 1995 John Wiley & Sons, Inc.
Angular spectral‐domain inversion of a conducting cylinder by using the physical optics approximation
Authors: Park Kong‐Mahn , Ra Jung‐Woong 
Published: July 2007

AbstractConducting cylinders are reconstructed from the multistatic, multifrequency, and multiincidence data of the scattered fields represented by the summation of their angular propagating modes. Physical optics approximation is assumed in the formulation of the reconstruction of the object shape function. Steps to obtain optimum data points are shown for numerical reconstruction examples of elliptic and rectangular conducting cylinders.
Fabrication of low‐loss 45° integrated mirrors on dielectric optical waveguides
Authors: Joannes L. , Grimbert B. , Vilcot J. P. , Tchana W. , Decoster D. 
Published: July 2007

AbstractHigh‐density low‐loss dielectric optical interconnection is demonstrated on a monomode optical waveguide compatible with microelectronics technology. Low‐loss self‐aligned integrated mirrors (SAIM) on a dielectric (polyimide‐silicon nitride‐polyimide) optical waveguide have been fabricated. Optimization of the reactive ion etching process has been made in order to obtain vertical, homogeneous etched sidewalls. Using such a process, 45° integrated mirrors present reflection losses of 0.6 dB at a 830‐nm wavelength (quasi‐TE mode).
A full‐wave spectral‐domain analysis of an asymmetric gap microstrip discontinuity
Authors: Cicchetti Renato , Faraone Antonio 
Published: July 2007

AbstractA full‐wave analysis of an asymmetric gap microstrip discontinuity, carried out by means of the spectral‐domain approach (SDA), is presented. The reflection and transmission current coefficients are determined using an appropriate representation of the surface excited along the microstrip lines and near the discontinuity. Some numerical results are presented, and interesting coupling effects, associated with the electro‐dynamic phenomena, are emphasized.
Nonlinear evolution of polarization in long‐haul fiber links and performance evaluation of polarization modulation systems
Authors: Matera F. , Mecozzi A. , Settembre M. 
Published: July 2007

AbstractThe evolution of the polarization state in nonsoliton long‐haul fiber links is studied theoretically. If dispersive effects are absent, an analytical theory permits prediction of the length scale over which light depolarization occurs. The presence of dispersive effects is analyzed by computer simulations. The performance of systems based on polarization modulation is evaluated in terms of eye degradation penalty.
A current generator for pseudomorphic FET large‐signal models
Authors: Gerard H. , Mouquet Y. , Rullier L. 
Published: July 2007

AbstractThis article presents a new model of drain current generator suitable for pseudomorphic FETs. The modeling of this generator is based on the integration versus VGS of the rf small‐signal transconductance gm. Pulsed measurements of IDS(VDS, VGS) are performed to verify the validity of the simulation results obtained when using the MDS simulator. © 1995 John Wiley & Sons, Inc.
Multilevel fast‐multipole algorithm for solving combined field integral equations of electromagnetic scattering
Authors: Song J. M. , Chew W. C. 
Published: July 2007

AbstractThe fast multipole method (FMM) has been implemented to speed up the matrix‐vector multiply when an iterative method is used to solve the combined field integral equation (CFIE). FMM reduces the complexity from O(N2) to O(N1.5). With a multilevel fast multipole algorithm (MLFMA), it is further reduced to O(N log N). A 110, 592‐unknown problem can be solved within 24 h on a SUN Sparc 10. © 1995 John Wiley & Sons, Inc.
A simple formulation of the boundary integral method for the analysis of arbitrarily shaped dielectric waveguides
Authors: Gentili G. G. , Mazzetto S. , Vaninetti G. 
Published: July 2007

AbstractA simple method for the vectorial analysis of arbitrarily shaped dielectric waveguides is discussed. The method is characterized by the application of Green's second identity to a set of plane waves as weighting functions for the internal problem. The method is attractive because of its simplicity and effectiveness. © 1995 John Wiley & Sons, Inc.
Analysis of an optical bent RIB waveguide by the imaginary‐distance beam‐propagation method
Authors: Seo Chulhun 
Published: July 2007

AbstractThe purpose of this article is to analyze efficiently a bent optical waveguide that is connected by two straight symmetric optical waveguides by the 3D imaginary‐distance beam‐propagation method (BPM). The BPM is implemented with 3D finite difference. We can obtain propagation constants and the field profile for the fundamental mode. © 1995 John Wiley & Sons, Inc.
Study of temperature‐measurement error of a fiber‐optic probe in a microwave field
Authors: Yiping Han 
Published: July 2007

AbstractWhen a fiber‐optic thermometer is placed in a microwave field to measure temperature, there will be energy loss due to electromagnetic interaction, which will certainly bring error in the measured temperature, within the sensor. In this article we have simplified the sensor to a finite‐length cylinder, and calculated the energy loss and temperature error. In addition, the measurement error of temperature is studied for a practical thermometer transducer fiber‐optic sensor placed in a microwave field. © 1995 John Wiley & Sons, Inc.