bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tunable fin‐line—microstrip oscillator
Authors: Xue Quan , Xu Jun , Xue Liangjin , Lin Weigan 
Published: July 2007

AbstractThe frequency of a microstrip oscillator is difficult to tune. A new millimeter‐wave microstrip Gunn oscillator is introduced in this Letter. Consisting of fin line and microstrip with microstrip as the output‐port transmission line, this Gunn oscillator can be mechanically frequency tuned. A Ka‐band oscillator of this structure is developed. The tuning bandwidth of this oscillator can reach 7.5 GHz or more with an output power of more than 70 mW. © 1994 John Wiley & Sons, Inc.
Power‐gain and fmax equations based on the T equivalent circuit of high‐frequency bipolar transistors
Authors: Seo Youngseok , Kim Bumman 
Published: July 2007

AbstractAnalytical expressions for the maximum available power gain and fmax of a high‐frequency bipolar transistor are derived from the simple T equivalent circuit model of bipolar transistors. These equations predict the power gain of the state‐of‐the‐art microwave bipolar transistor very well and show that f/max and power gain are proportional to the transconductance and decrease as the resistance‐capacitance charging time and current gain delay time increase. © 1994 John Wiley & Sons, Inc.
Application of the discrete fourier transform in the 2D‐FDTD method
Authors: Chun Joong Chang , Park Wee Sang 
Published: July 2007

AbstractThe discrete Fourier transform of a modal expansion in the 2D‐FDTD method is investigated theoretically to explain the appearance of the magnitude peaks and phase changes in the transform. It is shown that an eigenfrequency exists between two frequencies having a phase difference of 180 degrees. An algorithm using this property is proposed to improve the accuracy in the determination of the eigenfrequency, which is independent of the frequency resolution inherent in the 2D‐FDTD method. An example of a boxed anisotropic microstrip line is treated, and its result is compared with previous numerical ones. © 1994 John Wiley & Sons, Inc.
Design procedure of a 30‐GHz HEMT hybrid gate mixer
Authors: Kolanowski C. , Allam R. , Crosnier Y. 
Published: July 2007

AbstractThis article reports on a hybrid HEMT gate mixer exhibiting 4 dB of conversion gain and a 15‐dBm third‐order intermodulation intercept point at 28.5 GHz. These excellent performances have been made possible by a special design procedure that allows us overcome the problems inherent in the realization of hybrid circuits in millimeter‐wave ranges particularly the parasitic effects of bonding. © 1994 John Wiley & Sons, Inc.
Optical bistability in a one planar 3 × 3 coupler fiber‐ring resonator with degenerate two‐wave mixing
Authors: Ja Y. H. 
Published: July 2007

AbstractA theoretical study of optical bistability in a Type 1 one (planar 3 × 3) coupler fiber‐ring resonator with an all‐fiber scheme, Scheme B, of degenerate two‐wave mixing (DTWM) is presented. The bistability is caused by the DTWM, the inherent positive feedback in the fiber‐ring resonator and the nonlinear dependence of the circulating intensity of the fiber‐ring resonator on the DTWM gain. The relations between the bistability and various parameters of the fibers and the planar 3 × 3 coupler are inuestigated. A comparison between the bistability in such a jiber‐ring resonator and that using an equilateral triangular 3 × 3 fiber coupler is also made. © 1994 John Wiley & Sons, Inc.
Tunable interconnection network using a thick photorefractive (PR) crystal
Authors: Wen M. , Yin S. , Yu Francis T. S. 
Published: July 2007

AbstractA tunable interconnection network using a photorefractive (PR) crystal with an array of diode lasers is proposed. The interconnection data are wavelength multiplexed in a PR crystal reflection‐type hologram. An N × N interconnection network can be realized by N holograms, for which the network can be reconfigured in real‐time mode. © 1994 John Wiley & Sons, Inc.
Optimization of a power pseudomorphic double heterojunction FET
Authors: Gaquière C. , Théron D. , Bonte B. , Crosnier Y. 
Published: July 2007

AbstractIn this article we report the optimization of a power double heterostructure pseudomorphic FET. A ID model is used for charge control calculation and a 2D simulation for breakdown analysis. These simple models have allowed us to determine the suitable doping densities and device structure for maximum current density and breakdown performances. The results have been applied to the design of a 0.3‐μm × 70‐μm device. At 33 GHz it delivers an output power density of 1 W/mm with 5.7‐dB linear gain and 38% power added efficiency. © 1994 John Wiley & Sons, Inc.
Wave‐function solution of plane‐wave scattering by an anisotropic circular cylinder
Authors: Wu Xin Bao , Ren Wei 
Published: July 2007

AbstractAn analytical solution of plane‐wave scattering by an anisotropic circular cylinder is given in terms of the wave functions for anisotropic media. The T matrix of an anisotropic circular cylinder is derived. Numerical results in the low‐frequency range are used to check our calculations, and those in the resonance region are also presented.
Hybrid ppm‐cdma systems utilizing optical orthogonal codes for indoor wireless infrared communication
Authors: Elmirghani Jaafar M. H. , Cryan Robert A. 
Published: July 2007

AbstractAn original hybrid pulse position modulation code division multiple access (PPM‐CDMA) scheme is proposed and studied in the context of the indoor infrared communication network. The use of optical orthogonal codes (OOC) is proposed and original results are presented illustrating the improvement in bit rate achieved by utilizing PPM‐CDMA rather than on/off keying (OOK) CDMA. Results are presented for the maximum number of users that can communicate over the network at a given bit rate and it is shown that there exists an optimum PPM order, at a given number of users, that maximizes the achievable bit rate. Original results are presented for the false‐alarm errors due to the OOC cross correlations, and the optimum system operating parameters that minimize these errors are specified.
Generalized transmission line model for cylindrical‐circular microstrip antennas
Authors: Wong Kin‐Lu , Huang Chih‐Yu , Liu Yu‐Hua 
Published: July 2007

AbstractThe generalized transmission line model (GTLM) analysis has been applied to the study of cylindrical‐circular microstrip antennas. In this study, the equivalent circuit for the circular microstrip antenna excited at TM11 mode is given, and formulation of the input impedance is derived. Numerical results of the input impedance for different feed positions and cylinder radii are calculated and presented, and the accuracy of the GTLM analysis is discussed.
Theoretical analysis of multiple‐phase‐shift‐controlled distributed feedback wavelength tunable optical filters
Authors: Tan P. W. , Ghafouri‐Shiraz H. , Lo B. S. K. 
Published: July 2007

AbstractA three‐phase‐shift‐controlled wavelength tunable optical filter is proposed. Theoretical calculation based on the transfer matrix method indicates a tuning range of more than 30 Å. The peak gain and bandwidth are almost constant during tuning. The side‐mode suppression is over 25 dB.
Alternative formulations of electric dyadic green's functions of the first and second kinds for an infinite rectangular waveguide with a load
Authors: Li L. W. , Kooi P. S. , Leong M. S. , Yeo T. S. 
Published: July 2007

AbstractAlternative expressions of the dyadic Green's function for an infinite rectangular waveguide with and without a load are presented for defining the electromagnetic fields due to a microstrip patch, a slot, and an equivalent magnetic surface source placed along the broad and narrow walls. The alternative formulations of the dyadic Green's functions are given in terms of rectangular vector eigenfunctions defined by using the piloting vector y and z instead of the conventional z. The sign change in the z direction involved in the double numerical integration influences the accuracy and stability of the numerical computation. The alternative forms of the dyadic Green's functions can be used to overcome this problem in the practical applications.
Quasistatic solution of a cylindrical microstrip line mounted inside a ground cylinder
Authors: Tsai Ruenn‐Bo , Wong Kin‐Lu 
Published: July 2007

AbstractA new configuration of a cylindrical microstrip line mounted inside a ground cylinder is studied. Quasistatic expressions of the effective dielectric constant and characteristic impedance for such a microstrip line are derived. Numerical results are also calculated and compared with those obtained for a corresponding planar microstrip line. It is also found that the quasistatic characteristics for such a microstrip line with various curvatures are in contrast to the case of a cylindrical microstrip line mounted on a ground cylinder.
Input impedance and radiation pattern of a probe‐fed cylindrical annular‐ring microstrip antenna
Authors: Chen Horng‐Dean , Wong Kin‐Lu 
Published: July 2007

AbstractAnalysis of a probe‐fed annular‐ring microstrip antenna mounted on a cylindrical surface is presented. The analysis is performed by using cavity‐model theory. Expressions of the input impedance and far‐zone radiated fields are formulated and given. Numerical results for the antenna excited at the TM12 mode are also calculated and presented, and the effects of different feed positions and cylinder radii on the input impedance and radiation pattern are analyzed.
On the accuracy of analytical expressions for calculating the parameters of coplanar strips on a finitely thick substrate
Authors: Zhu Ning Hua , Wang Zi Qian , Lin Weigan 
Published: July 2007

AbstractAnalytical expressions for calculating the quasistatic parameters of coplanar strips and modified coplanar strips on a finitely thick substrate were derived through analyzing the structure with the complementary electrodes on the same substrate [1, 2]. In this Letter we use conformal mapping techniques to investigate the accuracy of these expressions.
Novel approach to contiguous band multiplexer design for satellite applications
Authors: Chahine Mohamed Khaled , Carrer Gérard 
Published: July 2007

AbstractA novel and general technique for the optimization of contiguous band multiplexers using sensitivity analysis is presented. The method utilizes exact partial derivatives of circuit responses with respect to all design parameters. The equivalent circuit includes channel filters, waveguide spacings, and three‐port waveguide junctions. A 12‐channel contiguous multiplexer at Ku band has been designed. Utilization of an efficient modelization and automatic decomposition approaches resulted in an excellent simulation performance of the presented multiplexer.
Feasibility study of a new heterodyne technique based on HgCdTe varactor photodetectors for space‐borne wind lidars
Authors: Chaubet M. , Mollier J. C. , Sage J. P. , Roizes A. , Aubry Y. 
Published: July 2007

AbstractDoppler Lidar is a good candidate for wind velocity measurement. But the total Doppler shift experienced by the backscattered laser pulses with a conical scanning instrument varies in a wide frequency range. Narrowing intermediate frequency bandwidth could provide better performances for both detection and low noise amplification. Therefore, optical mixing and parametric amplification in the same device have been investigated with HgCdTe photodetectors cooled at liquid nitrogen temperature. The optical and microwave setup needed for simulating Doppler and testing these detectors is described. Some experimental results, which demonstrate the feasibility of this new heterodyning process, are given. © 1995 John Wiley & Sons. Inc.
ISOMOM: A new method for reducing storage and execution time of moment‐method solutions in electromagnetics
Authors: Volakis John L. , Krestianinov Sergey V. 
Published: July 2007

AbstractA new method, referred to as ISOMOM, is presented for reducing storage and execution time of standard moment‐method solutions. ISOMOM isolates the dominant elements of the moment‐method matrix using a smooth filter function on the integral equation kernel, and this leads to sparse matrix systems with about 20% or less nonzero elements. The method is applied to the metallic strip electric field integral equation for illustrative purposes. © 1995 John Wiley & Sons. Inc.
Optimum design of an optical waveguide modulator in a fin line
Authors: Chen Shu‐Qiang , He Yu‐Xin , Ye Pei‐Da 
Published: July 2007

AbstractIn this article an optimum design of optical waveguide modulator in a fin line is given using the spectral‐domain method and the spectral‐domain immittance approach. It takes into account the thickness of the lithium niobate (LiNbO3) plate, the width of the slot, and the position of the optical waveguide. An example at 3‐cm wave band is given. © 1995 John Wiley & Sons. Inc.
Shorted annular patch antenna
Authors: Di Massa Giuseppe , Mazzarella Giuseppe 
Published: July 2007

AbstractA new type of annular patch antenna is presented. At variance of classical annular patch antenna the inner edge is shorted by a cylindrical conducting wall. Therefore this antenna radiates as a circular patch but has a smaller stored energy, which allows a larger bandwidth, and the feed point can be chosen to have an easy matching. © 1995 John Wiley & Sons. Inc.
Mode degeneracy in quasioptical resonators
Authors: Monahan G. P. , Heron P. L. , Steer M. B. , Mink J. W. , Schwering F. K. 
Published: July 2007

AbstractFabry‐Perot resonators and beam waveguides are used in quasioptical systems to refocus electromagnetic fields. These fields are described by Laguerre Gaussian or Hermite Gaussian quasi‐TEM mode families depending on whether the aperture is rectangular or circular. It is shown that certain lower‐order Laguerre Gaussian and Hermite Gaussian modes are identical. This has implications for the design of quasioptical systems for mode selection. © 1995 John Wiley & Sons. Inc.
Proposal and experiment of a novel Er‐doped fiber‐ring laser to suppress mode instability induced by polarization fluctuation
Authors: Shi Chao‐Xiang , Yamashita Shinji , Hotate Kazuo 
Published: July 2007

AbstractA novel Er‐doped fiber‐ring laser having less mode instability due to polarization fluctuation is proposed and experimentally investigated. The Er‐doped fiber is twisted to form a fiber‐ring laser. The right‐hand‐ and the left‐hand‐rotated circular waves preserved in the twisted fiber are exchanged by a fiber type ½ element placed in the fiber ring. This configuration can fix the separation between two polarization resonances (i.e., two ESOPs' resonances) and suppress the polarization‐mode instability. Both theory and experiment are presented conducted; the experiment his confirmed our design. In addition, the temperature effects on this fiber‐ring laser have been measured © 1995 John Wiley & Sons. Inc.
Interpolation of shaped reflector surfaces by cubic pseudosplines
Authors: Bergmann J. R. , Hasselmann F. J. V. 
Published: July 2007

AbstractA recent study demonstrated the superior stability of quintic pseudosplines, when compared with usual oscillatory series expansions, for global interpolation of numerically defined reflector surfaces presenting critical behavior of their principal curvatures. Although interpolating functions with continuous derivatives up to second order are necessary for ray‐optical field evaluations, C‐class surface descriptions are sufficient when the antenna secondary field is calculated by integration of physical‐optics‐induced currents. In this connection, the applicability of cubic pseudosplines is explored via numerical comparison with previously obtained results from the implementation of the quintic ones. © 1995 John Wiley & Sons. Inc.
Realization of first‐order monotonic butterworth‐type low‐pass and high‐pass optical filters: Experimental verification
Authors: Ngo Nam Q. , Dai X. , Binh Le Nguyen 
Published: July 2007

AbstractWe present an experimental implementation of the first‐order monotonic Butterworth‐type low‐pass and high‐pass optical filters, using a coherent all‐zero fiber‐optic filter (AZFOF), as a verification of our previously proposed theory [1]. The filter realization technique shows that the all‐fiber Mach‐Zehnder interferometer (AFMZI) belongs to a special class of the first‐order monotonic Butterworth‐type optical filter. The phase‐modulated AZFOF is shown to be a potential candidate as a tunable optical blocking filter. © 1995 John Wiley & Sons. Inc.
A useful fractional linear transformation for the riccati equation for reflection coefficients
Authors: He Sailing 
Published: July 2007

AbstractThe conventional Riccati equation for the reflection coefficient involves the spatial derivative of the refractive index, and thus it is not suitable for use when the refractive index is nondifferentiable and/or discontinuous. In the present article we introduce a fractional linear transformation to obtain a Riccati equation that does not involve the derivative of the refractive index. The transformed reflection coefficient is continuous everywhere in space for any refractive index profile. The transformed Riccati equation is also used to obtain an explicit solution for a multi‐layered structure in a straightforward way. © 1995 John Wiley & Sons. Inc.
Radar cross‐section reduction by polarization rotation
Authors: Ongareau Eric , Roussaud Alain , Marouby Eric , Levrel Jean‐René 
Published: July 2007

AbstractA system formed by a cascade connection of meander‐line strip grating surfaces that rotates the polarization plane of a linearly polarized wave is reported and measured. Reflectivity measurements of the system shaped on a reflector‐backed metallic ground plane have shown reflectivity levels smaller than –20 dB over the 10.5–17‐FHz band. © 1995 John Wiley & Sons. Inc.
A collocation‐type method for the solution of inverse problems in dispersive scattering theory
Authors: Razzaghi Mohsen , Ahmad Falih 
Published: July 2007

AbstractThis article introduces a numerical technique for solving the inverse problem in dispersive scattering theory. The inverse problem is first formulated as a relationship between the impulse response R and the susceptibility kernel G. Using the Legendre‐Gauss‐Lobatto nodes we construct the Nth polynomial interpolation to approximate the solution of G for a given R. This method is efficient and yields very accurate results. Illustrative examples are included to demonstrate the accuracy of the proposed method. © 1995 John Wiley & Sons, Inc.
Superresolved time‐frequency processing of wideband radar ECHO using esprit
Authors: Moore J. , Trintinalia L. C. , Ling H. , Xu G. 
Published: July 2007

AbstractA time‐frequency superresolution procedure is presented for processing wideband backscattered data containing both scattering center and natural resonance information. In this procedure, the ESPRIT algorithm is used as the processing engine. The windowed superresolution procedure is performed twice—once in the frequency domain to extract the scattering centers and once in the time domain to extract the resonances. Parametrized models for both scattering centers and resonances are obtained by a weighted average of the results for each segment. The resulting time‐frequency image from the present superresolution procedure is not constrained in resolution by the Fourier limit. Superior noise performance is also demonstrated against a similar Prony procedure reported earlier. © 1995 John Wiley & Sons, Inc.
A numerical absorbing boundary condition for 3D edge‐based finite‐element analysis of very low‐frequency fields
Authors: Boag Amir , Mittra Raj 
Published: July 2007

AbstractThe numerical absorbing boundary condition (NABC) approach in conjunction with the three‐dimensional edge‐based formulation of the finite‐element method (FEM) is applied to the problem of very low frequency (VLF) electromagnetic radiation and scattering. The key step in the NABC approach is to derive linear relationships that link the values of the field along the boundary edges to those at the neighboring ones. Derived via a robust SVD‐based scheme, these linear relationships are satisfied, to within a certain tolerance, by all of the outgoing weve components. They can thus be used in lieu of the FEM equations employing the usual absorbing boundary conditions for the boundary edges. Although the NABC approach provides a simple way to derive an accurate local boundary condition for mesh truncation at an arbitrary frequency, it appears to be the only viable absorbing boundary condition at VLF, because the conventional absorbing boundary conditions are almost as reflecting as perfectly conducting magnetic walls at these frequencies. © 1995 John Wiley & Sons, Inc.
Miniaturization method for matched MIC LNA design at low microwave frequencies
Authors: Bayar Esen 
Published: July 2007

AbstractA miniaturization technique is described, based on multiple function assignments to a single component or a small set of discrete components. This approach provides considerable substrate reduction without compromising electrical performance. The effectiveness of the technique is illustrated with a miniaturized L‐band LNA designs of outstanding electrical performance. © 1995 John Wiley & Sons, Inc.
On the design of multifunctional microwave (sub)systems for signal and noise performance
Authors: Rizzoli Vittorio , Costanzo Alessandra , Mastri Franco 
Published: July 2007

AbstractThe conventional approach to microwave system design based on the separate optimization of individual nonlinear functional blocks may result in a strongly suboptimal electrical and noise performance of the assembled system. This is due to nonlinear interactions among the interconnected subsystems, which are unpredictable by conventional means. The state equations of the individual building blocks change after the connection, and this may strongly modify the system electrical and noise performance with respect to the predictions. In order to meet the design goals it may thus be necessary to carry out a simultaneous numerical optimization of the entire assembly for electrical and noise performance, which is currently made possible by state‐of‐the‐art harmonic‐balance‐based numerical techniques. The optimized system performance may exceed the predictions based on the interconnection of noninteracting individually optimized subsystems, thanks to a better exploitation of the available degrees of freedom. © 1995 John Wiley & Sons, Inc.
An on‐wafer method for C‐V characterization of heterostructure diodes
Authors: Stake Jan , Grönqvist Hans 
Published: July 2007

AbstractAn on‐wafer method using coplanar probes for characterizing heterostructure diodes is proposed. Parameters are extracted by fitting a circuit model to a measured reflection coefficient over a broad frequency range. The test structure can be easily fabricated. © 1995 John Wiley & Sons, Inc.
Analysis of some coplanar transmission lines: Coplanar coupled lines, coplanar coupled striplines, and coplanar coupled lines with rectangular microshield
Authors: Yuan Naichang , He Jianguo , Yao Demiao , Dai Qin , Lin Weigan 
Published: July 2007

AbstractTwo types of coplanar transmission lines, rectangular microshield coplanar coupled lines (RMCCL) and coplanar coupled rectangular microshield lines (CCRML), are proposed for MMIC applications. These are developed from coplanar coupled lines (CCL) and coplanar coupled strip lines (CCS). Analytic formulas are presented for calculating the quasistatic TEM parameters of these coupled lines by means of exact conformal mapping techniques. Numerical results are also presented to illustrate the properties of these coplanar transmission lines. © 1995 John Wiley & Sons, Inc.