bluuebunny/crossref_metadata_2025_split huggingface dataset:
An efficient algorithm for solution of a scattering problem
Authors: Wang Y. M. , Chew W. C. 
Published: July 2007

AbstractAn object can always be subdivided into N subobjects. Hence, the scattering solution of an arbitrary‐shape inhomogeneous scatter can be formulated as a scattering solution of N scatterers, each of whose scattered field is approximated by M harmonics. This results in an NM unknown problem. A previously developed recursive operator algorithm, now adapted for wave scattering problems, can be used to solve this N scatterer problem. It is shown that the computational time of such an algorithm scales N2M2P where P is the number of harmonics used in the translation formulas. The scattered field from the same arbitrary shape scatterer can also be conventionally solved by the method of moments, casting it into an N linear algebraic equation. The solution of the linear algebraic equation via Gauss' elimination will involve order N3 floating‐point operations. Hence, the complexity of the recursive operator algorithm is of lower order than the method of moments. It is shown that the recursive operator algorithm is more efficient than the method of moments when the number of unknowns is large.
Very high‐isolation all‐fiber wavelength‐division multi / demultiplexer
Authors: Luo X. B. , Hu L. , Lin W. G. 
Published: July 2007

AbstractSuccessive fused‐taper couplers for wavelength‐division multiplexing are proposed as all‐fiber wavelength division multi / demultiplexers with very high isolation. A low‐loss (0.4 dB) multi / demultiplexer providing 41‐dB isolation at 1.300 μm and 50 dB at 1.550 μm is obtained.
Ka‐Band propagation characteristics of microstrip lines on GaAs substrates at cryogenic temperatures
Authors: Romanofsky R. R. , Martinez J. C. , Viergutz B. J. , Bhasin K. B. 
Published: July 2007

AbstractEffective permittivity and loss characteristics of gold microstrip lines on GaAs substrates were obtained by characterizing GaAs linear resonators at cryogenic temperatures (300 to 20 K) from 30‐40 GHz. A slight decrease in effective permittivity and a significant reduction in loss were observed with lower temperatures.
Power stored in the evanescent modes of a rectangular waveguide generated by a narrow inclined sidewall slot
Authors: Roy Rajat 
Published: July 2007

AbstractAn alternative expression for the internal power storage in the evanescent modes of a rectangular waveguide due to the presence of a narrow inclined slot on its sidewall to that already given by Hsu and Chen is obtained. The expression is in a closed form, thus doing away with numerical integration.
Crosstalk in a dpsk FDM system affected by laser phase noise
Authors: Betti S. , de Marchis G. , Iannone E. , Todaro M. 
Published: July 2007

AbstractIn this paper the crosstalk penalty for a DPSK FDM system is evaluated by an accurate analytical model taking into account the laser phase noise. The results are also compared with those obtained in the presence of phase noise from the Gaussian approximation to assess the conditions under which this simple algorithm can be used to evaluate the crosstalk induced penalty.
A finite‐difference frequency‐domain approach for solving electromagnetic scattering by conducting bodies of revolution
Authors: Joseph J. , Gordon R. K. , Mittra R. 
Published: July 2007

AbstractIn this paper, the problem of electromagnetic scattering by a conducting body of revolution is solved using the finite‐difference technique in frequency domain. Two coupled partial differential equations, derived based on the coupled azimuthal potentials introduced by Morgan, Chang, and Mei are solved over a domain surrounding the scatterer. Boundary‐fitted curvilinear coordinates, which avoid the problem of staircasing, are used to discretize the domain of computation. Results are presented to demonstrate the accuracy of the method.
Nonstandard variational method for calculating attenuation in optical fibers
Authors: Oksanen Markku , Mäki Hannu , Lindell Ismo V. 
Published: July 2007

AbstractA new variational functional for lossy open and dielectric waveguides has been derived. Based on the functional, a nonstandard variational method in terms of longitudinal fields has been introduced for calculating attenuation due to material losses. The method has been tested on a round step‐index optical fiber possessing various complex refraction index profiles.
A fast algorithm for solution of a scattering problem using a recursive aggregate τ matrix method
Authors: Chew W. C. , Wang Y. M. 
Published: July 2007

AbstractAn algorithm based on the recursive operator algorithm is proposed to solve for the scattered field from an arbitrarily shaped, inhomogeneous scatterer. In this method, the scattering problem is first converted to an N‐scatterer problem. Then, an add‐on procedure is developed to obtain recursively an (n + 1)‐scatterer solution from an n‐scatterer solution by introducing an aggregate τ matrix in the recursive scheme. The nth aggregate τ(n) matrix introduced is equivalent to a global τ matrix for n scatterers so that in the next recursion, only the two‐scatterer problem needs to be solved: One scatterer is the sum of the previous n scatterers, characterized by an nth aggregate τ(n) matrix; the other is the (n + 1)th isolated scatterer, characterized by τn + 1(1). If M is the number of harmonics used in the isolated scatterer T matrix and P is the number of harmonics used in the translation formulas, the computational effort at each recursion will be proportional to P2M. (Here we assume M is less than P.) Consequently, the total computational effort to obtain the N‐scatterer aggregate τ(N) matrix will be proportional to P2MN. In the low‐frequency limit, the algorithm is linear in N because P, the number of the harmonics in the translation formulas, is independent of the size of the object.
Modelling microstrip resonators with a dielectric protective layer for biomedical applications
Authors: Pribetich J. , Kennis P. , Pribetich P. 
Published: July 2007

AbstractPrevious modelization does not obtain the resonant frequencies of the rectangular microstrip resonator with a dielectric protective layer radiating into the human body (that is, the resonant frequency Fr and the Q factor), whereas this paper does. This analysis is based on the two‐dimensional spectral domain approach (SDA). Comparison with experiment shows that this method improves the previous one‐dimensional modelization.
Modeling and experimental study of breakdown mechanisms in multichannel AIGaAs/GaAs power hemts
Authors: Temcamani Farid , Crosnier Yves , Lippens Didier , Salmer Georges 
Published: July 2007

AbstractA theoretical and experimental analysis of breakdown in the power HEMT AlGaAs/GaAs single or multiple wells is presented in this article. The two phenomena ionization and tunneling have been considered. The understanding of breakdown mechanisms has led to definition of structures particularly suitable for power applications.
A 16 × 16 microstrip array of electromagnetically coupled patches operating in the high‐gain region
Authors: Lee R. Q. , Lee K. F. 
Published: July 2007

AbstractA microstrip array at 18.4 GHz consisting of 16 × 16 rectangular electromagnetically coupled patch antennas operating in the high‐gain region is experimentally investigated. The pattern and impedance characteristics of the array are compared with the case when the parasitic elements are removed.
A treatment by the FD‐TD method of the dispersive characteristics associated with electronic polarization
Authors: Kashiwa Tatsuya , Fukai Ichiro 
Published: July 2007

AbstractIn this article, the formulation of dispersive characteristics associated with an electronic polarization is discussed. The formulation is appropriate for use in the finite‐difference‐time‐domain (FD‐TD) method and is based on the equation of polarization. The validity of the formulation is verified by comparing the calculated complex dielectric constant with analytical values.
Accurate solutions for planar transmission lines by an improved singular integral equation technique
Authors: Huang Yafei , Xue Liangjin , Lin Weigan 
Published: July 2007

AbstractAn improved singular integral equation (SIE) technique is proposed which can be used for the analysis of finlines, microstrip lines, coplanar transmission lines, etc. The concepts of regular solution of the SIE and generalized characteristic equation are introduced. Numerical results show that it is an efficient and accurate method.
Achievement of low coupling loss between a 1.55‐μm wavelength laser diode and a high NA MCVD‐single‐mode fiber by conical microlens
Authors: Ghafouri‐Shiraz H. , Cameron K. , Fatah R. M. A. 
Published: July 2007

AbstractA low coupling loss of ‐1.34 dB has been achieved between a laser diode emitting at around 1.55 μm wavelength and a high numerical aperture MCVD single‐mode fiber by fabricating a conical microlens on the end surface of the fiber. Also for the same source a coupling loss of about ‐3dB has been achieved when a conventional MCVD single‐mode fiber with a core diameter of 7.3 μm was used.
Effects of multi‐pump beam coupling on intensity enhancement of a probe beam in photorefractive two‐wave mixing
Authors: Gilbreath G. C. , Davidson F. M. 
Published: July 2007

AbstractThe effects of three‐beam coupling are studied when two pump beams are photorefractively coupled to a probe beam of weaker intensity. Our work indicates that gain per unit effective length in the probe beam is affected by multiple‐pump beam interaction. Our work further indicates that reduced gain in the probe due to such interaction may be ameliorated by geometry, beam ratio, and material parameters. Experimental verification is presented using BaTiO3 and 514.5 nm.
Theoretical prediction of nonlinear brewster angle in ADP
Authors: Bhanthumnavin V. , Ampole N. 
Published: July 2007

AbstractThe intensity of reflected second harmonic light from the ADP (NH4H2PO4) crystal immersed in the optically denser liquid 1‐bromo‐naphthalene has been theoretically calculated, with the theory of Bloem‐bergen and Pershan, as a function of incident angle of the fundamental beam of Nd:YAG laser. A nonlinear Brewster angle θiNB of 43.32° is predicted.
A hybrid near‐optimum impedance transition with one discontinuity
Authors: Coetzee Jacob C. , Malherbe Johannes A. G. 
Published: July 2007

AbstractA near‐optimum impedance transition with one discontinuity consisting of a combination of the techniques proposed by Hecken and Klopfenstein is described. The aim is to utilize the attractive features of the two methods and to combine them in an alternative impedance matching technique that might be used in the design of wideband antenna elements with low return loss.
The stability of nonlinear TE, guided waves revisited
Authors: Zabeu A. C. P. , Souza J. R. 
Published: July 2007

AbstractThe propagation of nonlinear TE, guided waves is simulated numerically using a new algorithm based on variational and finite‐difference methods, and their stability properties are investigated. The results indicate that portions of the solutions are not only unstable but may follow a route to chaos through period doubling as the guided‐wave power increases.
Performances of superconducting interconnections
Authors: Kinowski D. , Huret F. , Seguinot C. , Pribetich P. , Kennis P. 
Published: July 2007

AbstractPulse propagation and crosstalk phenomena in metallic and superconducting coupled microstrip lines laid on semi‐insulating substrate are analyzed. Propagation characteristics of the studied lines are obtained through the well‐known spectral domain approach. Time domain results are determined by a fast Fourier transform. Effects of the nature of the strips are investigated.
Effect of a parasitic mode on the characteristics of a cylindrical waveguide mode converter with harmonically varying radius
Authors: Kasraian Masoud , Seshadri S. R. 
Published: July 2007

AbstractA cylindrical waveguide with harmonically varying radiius can be used to convert selectively the TEmq mode to the TEmp mode. The characteristics of this waveguide mode converter in the presence of the parasitic TEmr mode are treated, and a modified design for the improvement of the performance of this mode converter is presented.
A new spatial slice theorem for microwave imaging
Authors: Suh Kyoung‐Whoan , Kim Se‐Yun , Ra Jung‐Woong 
Published: July 2007

AbstractThe Fourier slice theorem, which was widely used in microwave radar imaging, is modified to be compatible in the spatial domain. Compared with the previous scheme, interpolation is not requisite for this spatial slice theorem. Numerical simulation for simple test targets is presented and its validity is discussed.
Tunability of cascaded grating used in distributed feedback laser
Authors: Moheimany O. R. , Rahnavard M. H. , Abiri H. , Alehassin M. 
Published: July 2007

AbstractReflectivity of cascaded gratings with phase shifts is studied. It is shown that this structure has wavelength tunability. The effects of phase shift, length of different stages of the gratings, and total length of grating for two and three cascaded grating stages on tunability are studied in this article.
Influence of tem waves on dielectric encapsulated semiconductor devices
Authors: Huang Kama , Lin Weigan 
Published: July 2007

AbstractThe influence of transverse electromagnetic (TEM) waves on dielectric encapsulated semiconductor devices is not attracting engineers' attention. It is found that the parameters of dielectric encapsulated semiconductor devices may degrade when these devices are radiated by TEM waves even though they are open circuited. Our experimental data exhibit that parameter degradations depend on the electric field strength and radiation time. Some discussions on these results are also given in this article.
Effect of metallization edge shape on conductor loss of open coplanar waveguide
Authors: Barsotti Edward L. , Kuester Edward F. , Dunn John M. 
Published: July 2007

AbstractThe effect on conductor loss of metallization edges with a trapezoidal shape instead of rectangular, as commonly occurs from ordinary fabrication techniques, is examined for the case of open coplanar waveguide. Depending on the geometric parameters, this can increase conductor loss by a significant amount.
Spectral domain analysis of microstrip antennas with an airgap
Authors: Tam W. Y. , Luk K. M. 
Published: July 2007

AbstractThe circular disk microstrip antenna with an airgap between the dielectric substrate and the ground plane is formulated using the spectral domain method. The complex resonant frequencies of the structure is determined using Galerkin's procedure. Some available experimental data are compared with the present method.
Analysis of a gaussian model for the far‐field intensity pattern of laser diodes
Authors: Ghafouri‐Shiraz H. , Gong J. 
Published: July 2007

AbstractA Gaussian model for the far‐field intensity pattern (FFIP) of semiconductor laser diodes is proposed based on a curve‐fitting technique. The analysis is carried out for different values of relative refractive index difference Δ and active layer thickness d ranging from 3% to 10% and 0.1 to 0.3 μm, respectively. The model is sufficiently accurate to be used in analyzing the coupling efficiency between laser diodes and single‐mode fibers.
Quasicomplex modes on lossy substrate boxed microstrip lines
Authors: Huret F. , Pribetich P. , Kennis P. 
Published: July 2007

AbstractIn this letter, by using a spectral domain approach improved by asymptotic expansions, we show by means of coupling integral values that the notion of quasicomplex modes can be introduced for lightly lossy substrates. The quasicomplex modes are particular modes with behavior similar to lossless structure complex modes.
Quantum‐well and quantum‐barrier diodes for generating submillimeter wave power
Authors: Grönqvist Hans , Kollberg Erik , Rydberg Anders 
Published: July 2007

AbstractQuantum‐well diodes have been used for generating power at millimeter and submillimeter waves, both in negative resistance oscillators and in multipliers. In this article, we will first discuss the power versus frequency and the maximum frequency of oscillation of “ordinary” quantum‐well oscillators. Possible methods of improving the power output and the maximum frequency of oscillation will be suggested. Quantum‐well diode multipliers will also be discussed. Realizing the importance of the nonlinear capacitance for the quantumwell diode multiplier efficiency, we have investigated a quantum‐barrier diode in multiplier applications.
GaAs Schottky barrier varactor diodes for submillimeter wavelength power generation
Authors: Crowe T. W. , Peatman W. C. B. , Winkler E. 
Published: July 2007

AbstractThere is interest in the development of heterodyne receivers for submillimeter wavelengths, particularly for space‐based remote sensing of the Earth's upper atmosphere. These receivers require solid‐state local oscillator sources. This article considers the fundamental design tradeoff that limits the cutoff frequency of varactor diodes. Recent results demonstrate a maximum cutoff frequency of 5 THz. and significant power to frequencies as high as 640 GHz.
A simple approach to a four‐way hybrid ring power divider design
Authors: Wang Jian , Spenuk Mike , Fralich Russell , Litva John 
Published: July 2007

AbstractA straightforward method is proposed for the design of a novel hybrid ring power divider that is compatible with stripline circuits. This configuration is analyzed using standard commercial CAD software TOUCHSTONEtm. Theoretical and experimental results show a return loss of better than −30 dB at the resonant frequency of the hybrid ring circuit and a transmission coefficient of −6.20 ± 0.15 dB in the band of interest (1.633‐1.666 GHz) with a maximum insertion loss of 0.35 dB (including connector effects).
Polarization dispersion in single‐mode optical fibers: A simpler formulation based on pulse envelope propagation
Authors: De Marchis G. , Iannone E. 
Published: July 2007

AbstractA new and simpler formulation of the theory of polarization delay and dispersion due to single‐mode optical fiber birefringence and coupling is presented. Exploiting its possibilities it is demonstrated that the polarization delay is the maximum delay between pulses injected into the fiber with orthogonal SOPs, and a relationship is found between the dispersion experimented by a pulse and the delay between this pulse and a pulse with the orthogonal SOP.
Anomalous microwave propagation in open space
Authors: Glakos George C. , Ishii T. Koryu 
Published: July 2007

AbstractIt has been observed in the far radiating zone that at a certain receiver antenna position and orientation the transit time of the arriving pulse‐modulated microwaves in open space was constant regardless of the distance between the receiver and the transmitter. The apparent phase velocity exceeded the intrinsic velocity. Calibration techniques employed and repeated time‐domain measurements done at different frequencies and distances confirmed this phenomenon.
Variation of gate and drain contact positions along the width of MESFETs and its influence on millimeter wave oscillator performance
Authors: Ongareau Éric , Bosisio Renato G. 
Published: July 2007

AbstractThe effects of gate and drain wave propagation of the contact positions along the electrodes of a GaAs MESFET oscillator are studied using a linear and distributed circuit analysis technique. Each distributed device element is considered as a combination of two pairs of coupled coplanar strips and a GaAs intrinsic MEFSET circuit. The distributed equivalent circuit is then analyzed using Touchstone with a chosen terminating load. The input impedance and reflection coefficient of the equivalent one‐port negative resistance MESFET oscillator are calculated as a function of input and output contact positions along the gate and drain of the device width. The results show, for a single gate MESFET of 600‐micron width, that the properties of transmission lines have some effect on the oscillator performance. Added power delivered by the negative resistance one‐port device also depends on gate and drain electrode contact position for a given load and terminating network. The drain contact position can be easily controlled by a circuit designer in MMIC such that the added power efficiency is obtained at no extra cost.
A microwave equivalent circuit model for semiconductor alloy ramp heterostructure diodes
Authors: Tait Gregory B. , Newman Harvey S. 
Published: July 2007

AbstractThe microwave impedance of a current‐rectifying Alx, Ga1‐x, As ramp heterostructure is measured from 0.1 to 12 GHz over a temperature range of 20 to 300 K. The elements of a small‐signal equivalent circuit model are optimized to fit the experimental impedance data over the full temperature and dc bias ranges. These circuit elements are identified with the physical structures and carrier transport mechanisms in the device.
Photopolymer hologram formation theory
Authors: Adhami Reza R. , Lanteigne David J. , Gregory Don A. 
Published: July 2007

AbstractA backward‐difference technique for the numerical solution of a nonlinear diffusion equation describing photopolymer hologram for mation is described. The monomer concentration, the net polymerization, and mass density changes are calculated and plotted as a function of the hologram's extent.
Analysis of a series‐fed aperture‐coupled patch array antenna
Authors: Wu Chen , Wang Jian , Fralich Russell , Litva John 
Published: July 2007

AbstractA full‐wave spectral domain model of a series‐fed, traveling‐wave aperture‐coupled patch array antenna is presented. This configuration allows for performance optimization by adjustment of the aperture size, aperture location, and patch size. The theory successfully predicts the input impedance and far‐field patterns of various C‐band configurations.
The electrostatic problem of a portion of a multilayer dielectric sphere in a uniform field
Authors: Lin Weigan , Liu Yuanan , Zhao Yushen 
Published: July 2007

AbstractWe develop a general multilayer dielectric sphere model in the toroidal coordinates and give the analytical electrostatic solution when it is excited by a uniform field. The special case of the electrostatic result of an incomplete conducting sphere can be obtained simply. It is in agreement with the published result. We have also found that the coating dielectric film on the conducting sphere surface can remarkably reduce distortion on the external homogeneous field when the normalized dielectric constant is from 1–5.
Theoretical and experimental determination of the power deposition of a microstrip‐microslot applicator for biomedical applications
Authors: Dubois L. , Bera J. , Pribetich J. , Chive M. 
Published: July 2007

AbstractWe propose to investigate printed circuit applicators for biomedical applications and especially the microstrip‐microslot applicator laid on multilayered lossy media and covered or not with a superstrate. Particular interest is focused on the power deposition inside biological tissues. The theoretical analysis is based on the spectral domain approach (SDA) method. In addition, experimental measurements were performed on phantom models of human tissue, which validate the theoretical study.
Anomalous acousto‐optic effect in glass
Authors: Taalbi Mustapha , Ishii T. Koryu 
Published: July 2007

AbstractA He‐Ne laser beam in glass plate is modulated by transversely applied audio frequency sound waves. The observed photodetected current showed phase shift in audio signals and frequency doubling depending on the location of the photodetector. The component of elliptical polarization showed modulation frequency sensitive transmission in glass.