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.

Hybrid Differential Evolution and Retrieval of Buried Spheres in Subsoil

Abstract: The characterization of conductive obstacles in subsoil is investigated in the induction regime. Validated by numerical experimentation, a simple model is proposed to calculate the main electromagnetic quantities of interest, the interaction between the obstacles being taken into account. The model is based on the extended Born approximation, the Lax-Foldy multiple diffraction theory, and introduction of equivalent spherical obstacles. Those are retrieved via a hybrid algorithm of differential evolution using a communication strategy between groups, which in particular enables separation of coupled obstacles close to one another.

FEMSTER: an object oriented class library of discrete differential forms

Abstract: The FEMSTER finite element class library described in this paper is unique in several aspects. First, it is based upon the language of differential forms. This language provides a unified description of a great variety of PDEs and thus leads us directly to a concise and abstract interface to finite element methods. This language also unifies the seemingly disparate Lagrange, H(curl) and H(div) basis functions that are used in computational electromagnetics. Secondly, FEMSTER utilizes higher-order elements, bases, and integration rules. Higher-order elements are important for accurate modeling of curved surfaces. The use of higher-order basis functions reduces the demands put upon mesh generation, e.g. a billion element mesh is no longer required for a numerically converged solution. The FEMSTER class library is ideally suited for researchers who wish to experiment with unstructured-grid, higher-order solution of Poisson's equation, the Helmholtz equation, Maxwell equations, and related PDEs that employ the standard gradient, curl, and divergence operators.

Electromagnetic Field in Air Produced by a Horizontal Magnetic Dipole Immersed in Sea: Theoretical Analysis and Experimental Results

Abstract: In recent years, data transmission from seawater into air across the sea surface has attracted considerable interest and is essential for undersea sensing and networking applications. In particular, electromagnetic (EM) wave propagation across the sea surface via a seawater-air path has great potential for long-distance transmission, thus providing a possible solution for sensing and networking problems. However, current related theoretical analyses and experimental results are not sufficient to support research and development in the domain. Therefore, based on previous studies, this study theoretically and experimentally investigates EM wave propagation from a horizontal magnetic dipole (HMD), namely, a loop antenna immersed in seawater radiating into the air. A set of mathematical expressions is formulated for a model of three-layered conducting media on the basis of Maxwell's equations. In addition, a proof of concept measurement system was designed and built. A trial was conducted on the sea, and the results were in good agreement with the theoretical analysis. A horizontal transmission distance up to 574 m over the sea surface was achieved using a small loop antenna operated at 19 kHz and with an input power of less than 10 W. Therefore, the approach has been proven to be promising.

Asymptotic methods in electromagnetics

Abstract: All in all, the book is well written, and provides numerous entries for the CCIR (ITU-R) reports available and ready for use. Every chapter starts of with an introduction, and a summary of the chapter is given at its end. Except for the overlooked subjects (site shielding, deterministic modeling of propagation) the subject matter is well covered. The book provides what its title says. It is a practical and pragmatic introduction to radio propagation for fixed and mobile communications.

H- and H 2 -matrix-based fast integral-equation solvers for large-scale electromagnetic analysis

Abstract: Integral-equation (IE)-based methods generally lead to dense systems of linear equations. The resulting matrices, although dense, can be thought of as ‘data sparse’, that is, they can be specified by few parameters. Based on this observation, two fast IE-based methods were developed for large-scale electromagnetic analysis. One is a centre-point ℋ-matrix-based method of linear complexity for large-scale analysis of static problems or problems having small electric sizes. The other is an ℋ2-matrix-based method of controlled accuracy and linear complexity for large-scale analysis of electrodynamic problems across a wide range of electric sizes. Numerical simulations from a small number of unknowns to over 1 million unknowns, from small electric sizes to over 60 wavelengths have demonstrated the accuracy and efficiency of the proposed methods. The methods are kernel independent, and hence suitable for any IE-based formulation. In addition, they are applicable to arbitrarily shaped structures.