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.

Efficient solution of EFIE via low-rank compression of multilevel predetermined interactions

Abstract: This paper describes the predetermined interaction list oct-tree (PILOT) algorithm and its application in expediting the solution of full-wave electric field integral equation (EFIE)-based scattering problems for three-dimensional arbitrarily shaped conductors. PILOT combines features of the fast multipole method (FMM) and QR decomposition-based matrix compression techniques to optimize setup times, solve times, and memory requirements. The method is kernel independent and stable for electrically small structures unlike traditional FMM. The novel features of the algorithm, namely the mixed potential compression scheme and the hierarchical multilevel predetermined matrix structure are explained in detail. A complexity estimate is presented to demonstrate the scaling in time and memory requirements. Examples exhibiting the accuracy and the time and memory performances are also presented. Finally, a quantitative study is included to address the expected but gradual degradation of QR-based compression techniques for electrically large structures.

Electromagnetic Resonances and Q-Factors of Lossy Dielectric Spheres

Abstract: A theoretical and experimental study of the electromagnetic resonances of spheres is presented. In particular, the scattering characteristics of spheres inside rectangular waveguides are investigated at and around the resonant frequencies. The approach is based on the scattering theory developed by Mie in 1908. Mie's theory is valid for scattering of a plane electromagnetic wave by a homogeneous and isotropic sphere of arbitrary diameter. It encompasses both lossless and lossy spheres. Three continuous functions of frequency are presented. They contain information on the resonant frequencies, the Q-factors, and the output power losses of the sphere. The effect of losses on the resonant behavior was also studied. The theoretical results were compared to experimental data. The agreement between theory and experiment is excellent. An experimental study of the effect of inhomogenities and irregularities of the sphere's material and shape was also made.

A fast hybrid field-circuit simulator for transient analysis of microwave circuits

Abstract: A plane-wave-time-domain accelerated time-domain integral-equation solver is coupled to a SPICE-like transient circuit simulator to analyze electromagnetic platform-circuit interactions. The hybrid field-circuit simulator simultaneously solves surface-wire-volume time-domain integral equations that model electromagnetic interactions with the platform and modified nodal analysis equations that govern the behavior of the potentially nonlinear lumped circuits. A shielded nonlinear microwave amplifier is analyzed using the proposed scheme, and its immunity to electromagnetic interference is assessed.

Numerical aspects on coupling between complementary boundary value problems

Abstract: The consequences of nonuniqueness for integral equations used in the numerical resolution of electromagnetic scattering problems are investigated from a practical point of view. The scatterers are closed perfectly conducting cylinders of arbitrary cross section illuminated by a plane wave in both E and H polarizations. It is shown how to detect the frequencies at which nonuniqueness occurs, and how to avoid the resulting errors by the use of the notion of an equivalent problem. This approach is compared to other ones proposed by different authors. A new interpretation of the computed solution, when uniqueness conditions are not satisfied, is given and it is shown how to use such a solution in the computation of the resonant modes of the interior problem, even for degenerate modes.