ISSN:1050-1827    

DOI:10.1002/mmce.4570010202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA comparison of different methods for the characterization of planar line discontinuities with emphasis on microstrip discontinuities is given, thereby describing the present state of the art in this area of microwave circuit CAD. Quasi‐static equivalent circuit models, the magnetic wall waveguide model of microstrip discontinuities, full‐wave analysis techniques like the orthogonal series expansion and mode matching techniques, the spectral domain analysis technique using roof‐top functions, and the finite‐difference time‐domain technique are described briefly and compared with respect to their numerical efficiency and their cap

ISSN:1050-1827    

DOI:10.1002/mmce.4570010203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA review of active device models for microwave CAD simulators is presented. Large‐signal, nonlinear models are of particular interest. The basic techniques employed in deriving equivalent circuit and physically based models are reviewed. Various methods for solving the semiconductor device equations to establish physically based models are indicated. Finally, it is proposed that physically based, analytic GaAs MESFET models offer an attractive compromise between simulation efficiency and quantitative accuracy. The use of such a model is demonstrated by several examples, including comparison with experimental data. These models are suitable for use in comprehensive CAD workstation environments and allow process‐type device models to be interfaced directly with RF circuit simulat

ISSN:1050-1827    

DOI:10.1002/mmce.4570010204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe harmonic balance method is a technique for the numerical solution of nonlinear analog circuits operating in a periodic, or quasi‐periodic, steady‐state regime. The method can be used to efficiently derive the continuous‐wave response of numerous nonlinear microwave components including amplifiers, mixers, and oscillators. Its efficiency derives from imposing a predetermined steady‐state form for the circuit response onto the nonlinear equations representing the network, and solving for the set of unknown coefficients in the response equation. Its attractiveness for nonlinear microwave applications results from its speed and ability to simply represent the dispersive, distributed elements that are common at high frequencies.The last decade has seen the development and application of harmonic balance techniques to model analog circuits, particularly microwave circuits. The first part of this article reviewed the fundamental achievements made during this time. In this part, the extension of the method to quasi‐periodic regimes, optimization analysis, oscillator analysis, studies of various convergence strategies, and practical applications are discussed. A critical assessment of the various types of harmonic balance techniques is given. Examples of designs which have been modeled using the harmonic balance technique and built both in hybrid and MMIC form are

ISSN:1050-1827    

DOI:10.1002/mmce.4570010205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractFrequency‐domain nonlinear analysis techniques for the simulation of active microwave circuits solve the linear and nonlinear network equations entirely in the frequency‐domain. by so doing, they avoid the aliasing problems inherent in piecewise harmonic balance approaches. Consequently, frequency‐domain techniques have extremely wide dynamic range and easily accommodate high order multitone excitation. However, this is at the expense of requiring more restrictive nonlinear device models. There are a large number of frequency‐domain nonlinear analysis techniques but all are based on functional expansions which enable the frequency components of the output spectrum to be calculated directly from the input spectrum. These techniques have been used to analyze many nonlinear circuits and are the only candidates for the hierarchical simulation of nonlinear microwave circuits. This paper first uses frequency‐domain concepts to discuss nonlinear distortion phenomena, then, a review of the frequency‐domain nonlinear analysis literature is made with the aim of presenting the major advances in these

ISSN:1050-1827    

DOI:10.1002/mmce.4570010206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe computer‐aided simulation and design of microwave integrated circuits often leads to large‐size numerical jobs, especially for modern multiple‐device MMIC subsystems such as distributed mixers and amplifiers. When this is the case, the use of large computer systems such as vector processors may become very attractive, because of the dramatic reduction of wall‐clock time and of the related improvement of cost‐to‐performance ratio. This paper discusses the application of supercomputers to the solution of a number of such advanced microwave circuit CAD problems. An overview of the performance of general‐purpose vectorized algorithms such as system solvers and Fast Fourier Transforms is first presented, in order to give a feeling of the potential of this class of machines in microwave CAD applications. Then a few typical microwave engineering problems are specifically addressed, including the statistical design (yield optimization) of linear circuits, the analysis of nonlinear circuits under multitone excitation, and the optimization of ultrabroadband nonlinear subsystems. In each case, a possible vectorization strategy is studied in depth, and the structure and performance of a specific highly vectorized algorithm are descri

ISSN:1050-1827    

DOI:10.1002/mmce.4570010207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractMicrostrips are open structures, that tend to radiate as the frequency of the signal increases within the microwave range. Radiation becomes significant in the vicinity of discontinuities, particularly when parts of the structure resonate. This situation is encountered in the design of filters, which often are arrays of radiating dipoles. When circuits are placed within metal enclosures, the radiated waves are reflected on the walls, and produce interference.The mechanism of radiation is linked to the excitation of three kinds of waves: radiated waves, leaky waves, and surface waves. The latter remain trapped within the dielectric substrate and propagate with little attenuation (i.e., optical fibers), producing spurious coupling and diffraction.An analysis technique originally developed for patch antennas provides a means to rigorously analyze the radiation from unenclosed microstrip circuits. It is based on a mixed potential integral equation formulation (MPIE), making use of Green's functions provided by Sommerfeld integrals, for which an exact evaluation technique was developed. The currents flowing on the circuits are expanded over a set of subsectional basis functions, and their intensities are determined by a method of moments. This approach provides both the circuit parameters (impedance or scattering matrices), and its radiation characteristics (antenna pattern). It allows one to determine the effect produced by a radiating element on another one, even when the two are not closely located with respect to one another.

ISSN:1050-1827    

DOI:10.1002/mmce.4570010208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA comparison of radiation models for a rectangular patch antenna is made. The dominant mode electric current model and magnetic current model are each applied to the cases of a rectangular patch on an infinite substrate, and a patch on a substrate which is truncated at the edges of the patch. It is noted that exact agreement is obtained between the two models for the case of a resonant patch, for both the infinite substrate and truncated substrate cases. The effects of dielectric truncation on the radiation patterns is discussed and the electric current model is also extended to include the effects of feed‐probe radiation and radiation from higher‐order modes on the pa

ISSN:1050-1827    

DOI:10.1002/mmce.4570010209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:1050-1827    

DOI:10.1002/mmce.4570010210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:1050-1827    

DOI:10.1002/mmce.4570010201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY