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Article
Publication date: 1 March 1999

M.A. Kolbehdari and M.S. Nakhla

This paper describes an efficient reduced‐order method for the analysis of cylindrical dielectric resonators with an inhomogeneous dielectric medium. The field equations are…

135

Abstract

This paper describes an efficient reduced‐order method for the analysis of cylindrical dielectric resonators with an inhomogeneous dielectric medium. The field equations are formulated using the Laplace‐domain finite element method and are reduced to lower‐order models using the complex frequency hopping (CFH) technique. CFH is a moment matching technique which has been used successfully in the circuit simulation area for the solution of a large set of ordinary differential equations. The proposed technique is faster than the conventional approach by one to three orders of magnitude. The results are compared with those of other numerical methods available in the literature.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 18 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Available. Open Access. Open Access
Article
Publication date: 12 October 2022

Marissa Condon and Brendan Hayes

The paper is concerned with interpolatory proper orthogonal decomposition (IPOD) methods for nonlinear transmission line circuits. This paper aims to examine several factors that…

427

Abstract

Purpose

The paper is concerned with interpolatory proper orthogonal decomposition (IPOD) methods for nonlinear transmission line circuits. This paper aims to examine several factors that must be considered when applying such model reduction techniques to this kind of circuit.

Design/methodology/approach

Two types of POD will be implemented. In each case, the choice of the order of the reduced model and the order of the interpolation space shall be considered. The stability of the models shall be explored.

Findings

The results indicate that the order for the reduced model to obtain accurate results depends on the chosen method when considering nonlinear transmission lines. The results also indicate that the structure of the nonlinear transmission line is crucial for determining the stability of the reduced models.

Originality/value

The work compares two IPOD methods and discusses the issues involved in achieving an accurate and stable reduced-order model for a nonlinear transmission line.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 42 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Available. Open Access. Open Access
Article
Publication date: 13 June 2023

Marissa Condon

The purpose of the paper is the simulation of nonuniform transmission lines.

630

Abstract

Purpose

The purpose of the paper is the simulation of nonuniform transmission lines.

Design/methodology/approach

The method involves a Magnus expansion and a numerical Laplace transform. The method involves a judicious arrangement of the governing equations so as to enable efficient simulation.

Findings

The results confirm an effective and efficient numerical solver for inclusion of nonuniform transmission lines in circuit simulation.

Originality/value

The work combines a Magnus expansion and numerical Laplace transform algorithm in a novel manner and applies the resultant algorithm for the effective and efficient simulation of nonuniform transmission lines.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 43 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 September 1999

R. Albanese, G. Rubinacci, A. Tamburrino and F. Villone

In this paper a method is presented for an efficient solution of the direct problem (find the scattered field for a given thin crack and driving field) in the time domain. This is…

104

Abstract

In this paper a method is presented for an efficient solution of the direct problem (find the scattered field for a given thin crack and driving field) in the time domain. This is a fundamental step in any non destructive evaluation problem. Two different approaches, one in the time domain and the other based on Fourier analysis, are used and compared with reference to a configuration for which some experimental results are available. The advantages and drawbacks of the two approaches are briefly discussed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 18 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 12 July 2011

Lubomír Brančík

The purpose of this paper is to present the development and comparison of selected time‐domain and Laplace‐domain methods for the simulation of waves propagating along…

260

Abstract

Purpose

The purpose of this paper is to present the development and comparison of selected time‐domain and Laplace‐domain methods for the simulation of waves propagating along multiconductor transmission lines (MTLs), both uniform and nonuniform, and sensitivities with respect to distributed and lumped parameters of MTL systems.

Design/methodology/approach

A methodology is based on discrete, semidiscrete and continuous MTL models formulated and solved both in the time and Laplace domains, latter combined with a numerical inverse Laplace transform (NILT).

Findings

The most accurate method is that based on the MTL Laplace‐domain continuous model, processed via the MTL chain matrix and connected with an NILT. This method concurrently shows minimal RAM requirements, and in case of uniform MTLs, it runs fastest. For nonuniform MTLs, however, the implicit Wendroff formula is fastest, as long as the RAM is available.

Research limitations/implications

The research is limited to linear MTLs only and the methods suppose terminating circuits based on their generalized Thévenin equivalents. They can be, however, generalized for more complex systems via more sophisticated boundary conditions treatment. The time‐domain methods have further potential to be generalized towards nonlinear MTLs.

Practical implications

The methods considered can contribute to solving signal integrity issues in high‐speed electronic systems, the Matlab routines developed can serve in education process as well.

Originality/value

The implicit Wendroff formula has been adapted to enable simulation of voltage and/or current distributions and their sensitivities along the nonuniform MTLs' wires. Besides, semidiscrete and continuous nonuniform MTL models have been elaborated to enable sensitivities determination, both in the time and Laplace domains, latter connected with the NILT technique based on fast Fourier transform/inverse fast Fourier transform and quotient‐difference algorithms.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 September 2005

Sonia Leva and Adriano Paolo Morando

To provide a unified analytical tool, based on Park transformation, for the theoretical and practical analysis of a lossy three‐phase transmission line.

576

Abstract

Purpose

To provide a unified analytical tool, based on Park transformation, for the theoretical and practical analysis of a lossy three‐phase transmission line.

Design/methodology/approach

The results obtained in the study of TEM waves propagation in two‐wire line can be extended to a symmetric m‐wire line by employing the modal analysis. This approach relates the dynamic of m‐wire guided field to the propagation of m modal voltages and currents acting on m single‐wire decoupled transverse electromagnetic (TEM) lines. In the symmetric three‐phase system case, the modal analysis includes, as a particular case for m=3, the symmetric component theory. In previous papers, the authors applied the Park transformation to study the wave propagation of (TEM) three‐phase symmetrical lines. The formulation proposed and tested considers the lossless TEM wave propagation of a three‐phase line without consideration to the dissipations phenomena present in the line itself. Taking into account the obtained results, the extension of the developed approach to the lossy three‐phase transmission line transient analysis is very useful on both theoretical and practical points of view.

Findings

The symmetrical three‐phase line Park model for the lossy transmission line transient analysis, regarded as vector formulation of the line modal analysis, has been presented. The proposed examples highlight how, thanks to the Park model, the dynamic analysis of the three‐phase line in distorted and unsymmetrical systems becomes an integral part of the more general and well‐established power electric system dynamic theory.

Originality/value

The three‐phase transmission line transient analysis presented in this paper emphasizes the conceptual contents, specific to the Park approach. Furthermore, it gives some results very important for the practical analysis of a lossy three‐phase transmission line.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 June 2004

Marissa Condon and Rossen Ivanov

This paper presents the application in circuit simulation of a method for model reduction of nonlinear systems that has recently been developed for chemical systems. The technique…

717

Abstract

This paper presents the application in circuit simulation of a method for model reduction of nonlinear systems that has recently been developed for chemical systems. The technique is an extension of the well‐known balanced truncation method that has been applied extensively in the reduction of linear systems. The technique involves the formation of controllability and observability gramians either by simulated results or by measurement data. The empirical gramians are subsequently employed to determine a subspace of the full state‐space that contains the most significant dynamics of the system. A Galerkin projection is used to project the system onto the subspace to form a lower‐dimensional nonlinear model. The method is applied to a nonlinear resistor network which is a standard example for exemplifying the effectiveness of a nonlinear reduction strategy.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 3 July 2017

Andrzej Karwowski

The purpose of this paper is to examine the convergence, offered accuracy and efficiency of the bisectional adaptive frequency sampling (AFS) scheme combined with the…

104

Abstract

Purpose

The purpose of this paper is to examine the convergence, offered accuracy and efficiency of the bisectional adaptive frequency sampling (AFS) scheme combined with the Stöer-Bulirsch (SB) algorithm as a tool for supporting frequency-domain method-of-moments (MoM) in broadband electromagnetic (EM) simulations.

Design/methodology/approach

The AFS and SB procedures have been interfaced with the MoM code, and then, an extensive parametric study has been carried out to explore the performance of the numerical solution for the test problems of reconstructing frequency responses of the wire radiator and scatterer, respectively, over at least a decade bandwidth.

Findings

The results give evidence for the efficiency of the overall approach and its capability of constructing the approximation of multi-resonant responses with sharp resonant peaks from a substantially reduced number of EM samples (data points) compared to that of conventional uniform sampling.

Originality/value

Results of the study offer thorough insight into the performance of the AFS-SB technique, and the data given in this paper may be helpful in selecting the convergence criterion and the tolerance for the AFS-SB algorithm to achieve a possibly economical broadband simulation technique.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 January 1994

J. Poltz

Digital systems utilize frequencies into the GHz range Attempts to reduce the propagation delay by lowering the interconnect capacitance (decreasing cross‐sectional dimensions…

31

Abstract

Digital systems utilize frequencies into the GHz range Attempts to reduce the propagation delay by lowering the interconnect capacitance (decreasing cross‐sectional dimensions) cause an increase in wire resistance which, in turn, increases the rise time and indirectly slows down the response Therefore, it is impossible to optimize VLSI and packaging interconnections to maximize the clock rate without analyzing losses (solving Helmholtz equation) and implementing lossy transmission line models This paper presents modeling and simulation of a gate array interconnect.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 January 2019

Mian Ilyas Ahmad, Peter Benner and Lihong Feng

The purpose of this paper is to propose an interpolation-based projection framework for model reduction of quadratic-bilinear systems. The approach constructs projection matrices…

166

Abstract

Purpose

The purpose of this paper is to propose an interpolation-based projection framework for model reduction of quadratic-bilinear systems. The approach constructs projection matrices from the bilinear part of the original quadratic-bilinear descriptor system and uses these matrices to project the original system.

Design/methodology/approach

The projection matrices are constructed by viewing the bilinear system as a linear parametric system, where the input associated with the bilinear part is treated as a parameter. The advantage of this approach is that the projection matrices can be constructed reliably by using an a posteriori error bound for linear parametric systems. The use of the error bound allows us to select a good choice of interpolation points and parameter samples for the construction of the projection matrices by using a greedy-type framework.

Findings

The results are compared with the standard quadratic-bilinear projection methods and it is observed that the approximations through the proposed method are comparable to the standard method but at a lower computational cost (offline time).

Originality/value

In addition to the proposed model order reduction framework, the authors extend the one-sided moment matching parametric model order reduction (PMOR) method to a two-sided method that doubles the number of moments matched in the PMOR method.

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