Computational electromagnetics

About: Computational electromagnetics is a research topic. Over the lifetime, 6412 publications have been published within this topic receiving 113727 citations. The topic is also known as: Electromagnetic field analysis.

A complexity-reduced H-matrix based direct integral equation solver with prescribed accuracy for large-scale electrodynamic analysis

Abstract: The Integral equation (IE) based computational electromagnetic methods generally lead to a dense system of linear equations, the solution of which could be very expensive. Recently, fast solvers [1–3] such as FMM-based methods, fast low-rank compression methods, FFT-based methods, and H2-matrix based methods have been developed, which dramatically reduce the memory and CPU time of iterative IE solvers for electrodynamic problems. Fast direct solvers have also been developed. LU factorization of O(N2) time complexity and O(N1.5) memory complexity was reported [4]. Compared to iterative solvers, direct solvers have advantages when the number of iterations or the number of right hand sides is large.

Compact Time-Domain Models of Complex RF Structures Based on the Real Eigenmodes of Segments

Abstract: Wideband modeling of complex loss-free isotropic RF structures is a challenging task in electrical engineering. This paper presents a new formalism to create compact wideband equivalent models of complex RF structures. In a first step, the complex structure is partitioned into segments. On the basis of the segment's eigenmodes with either vanishing tangential electric or magnetic fields on the boundary and a correction term, systems of ordinary differential equations (ODEs) are derived. In consequence, real eigenvalue problems need to be solved for each segment in addition to the actual field distribution in the segment, which only needs to be computed for a small number of discrete frequency samples for the correction term. Linking the established ODE systems of the segments with a suitable concatenation scheme leads to an ODE system for the entire structure. This system allows the computation of complex structure responses because of transient port excitation and the determination of transient 3-D fields in the structure. As a side product, the frequency-domain transfer function of the complex structure is available. Besides the theoretical derivations, two validation examples for the time-domain scheme are presented. These examples show that the method provides a good approximation of the transient processes in the structures under consideration.

Scattering by a groove in a conducting plane-a PO-MoM hybrid formulation and wavelet analysis

Abstract: A novel method is presented to solve the two-dimensional (2-D) problem of scattering of an electromagnetic plane wave by a groove in a perfectly conducting infinite plane. In this method, the unknown induced current is expressed in terms of the known physical optics solution of the unperturbed problem of scattering by an infinite conducting plane plus a yet to be determined localized correction current placed in the vicinity of the groove. It is then shown that a good approximation of the induced current can be obtained using only a few dominant functions in the wavelet expansion of the correction current. Moreover, the same set of dominant wavelet functions serves the purpose of approximating the induced current at different angles of incidence. A numerical example demonstrates these various features of the proposed method of solution.

Computational cost estimations and comparisons for three methods of applied electromagnetics (MoM, MAS, MMAS)

Abstract: The computational costs of three numerical techniques used in electromagnetics, namely the moment method (MoM), the method of auxiliary sources (MAS), and its modified version (MMAS), are estimated for various calculation schemes and configurations. Both surface and volumetric problems are considered. The number of multiplications required for the system-matrix fill is calculated and added to the algorithmic cost of the matrix inversion. The Green's function singularity extraction is also taken into account, particularly for the MoM. The original integrals are transformed into the local (area or volume) coordinate systems, and are subsequently evaluated on the basis of standard numerical quadrature schemes. For the surface integral equation (SIE), some calculations using either the well-known Duffy transformations or some analytical-numerical integration schemes are also presented (expressions are available only for the scalar potential integral case). For the MAS and MMAS, the matrix fill is shown to be much faster, since no time-consuming integrations are involved. The analysis is applied to various objects, such as a perfectly conducting (PEC) parallelpiped, a PEC sphere, and a microstrip patch antenna, and useful conclusions are drawn on the relative efficiency of the three methods.

Hybridization of FDTD and device behavioral-modeling techniques [interconnected digital I/O ports]

Abstract: We present a systematic methodology for the electromagnetic modeling of interconnected digital I/O ports. Digital drivers and receivers are represented through behavioral models based on radial basis functions expansions. Such a technique allows a very accurate representation of nonlinear/dynamic effects as well as switching behavior of real-world components by means of carefully identified discrete-time models. The inclusion of these models into a finite-difference time-domain solver for full-wave analysis of interconnected systems is presented. A rigorous stability analysis shows that use of nonlinear/dynamic discrete-time models can be easily integrated with standard full-wave solvers, even in the case of unmatched sampling time. A set of numerical examples illustrates the feasibility of this method.