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.

Near-field thermal electromagnetic transport: An overview

Abstract: A general near-field thermal electromagnetic transport formalism that is independent of the size, shape and number of heat sources is derived. The formalism is based on fluctuational electrodynamics, where fluctuating currents due to thermal agitation are added to Maxwell’s curl equations, and is thus valid for heat sources in local thermodynamic equilibrium. Using a volume integral formulation, it is shown that the proposed formalism is a generalization of the classical electromagnetic scattering framework in which thermal emission is implicitly assumed to be negligible. The near-field thermal electromagnetic transport formalism is afterwards applied to a problem involving three spheres with size comparable to the wavelength, where all multipolar interactions are taken into account. Using the thermal discrete dipole approximation, it is shown that depending on the dielectric function, the presence of a third sphere slightly affects the spatial distribution of power absorbed compared to the two-sphere case. A transient analysis shows that despite a non-uniform spatial distribution of power absorbed, the sphere temperature remains spatially uniform at any instant due to the fact that the thermal resistance by conduction is much smaller than the resistance by radiation. The formalism proposed in this paper is general, and could be used as a starting point for adapting solution methods employed in traditional electromagnetic scattering problems to near-field thermal electromagnetic transport.

Application of wavelets on the interval to the analysis of thin-wire antennas and scatterers

Abstract: An analysis of thin-wire antennas and scatterers using orthogonal wavelets on interval [0,1] is presented. The thin-wire version of the electric-field integral equation (EFLE) is solved by the hybrid wavelet expansion and boundary element method (HWBM). Maps between the curved solution domains and the interval [0,1] are established by using the geometrical representation of the boundary element method (BEM). By virtue of these maps, bases over the curved solution domains are derived from orthogonal wavelets on [0,1] that are used to expand the unknown current over the wires. The utilization of the wavelets on [0,1] circumvents the difficulties in the application of the wavelets on the real line to finite-domain problems and has no periodicity constraint to the unknown function that is usually imposed by the periodic wavelets. Numerical examples are provided for a variety of thin-wire antennas and scatterers.

Higher-order MoM implementation to solve integral equations

Abstract: Higher-order basis functions have received intensive attention for solving electromagnetic problems with the finite element and Galerkin's methods. The advantage of using higher-order basis functions lies in their ability to model the fields and sources, as well as geometries, more accurately than conventional low-order methods. We investigate the convergence properties of divergence conforming interpolatory higher-order basis functions for evaluating the Galerkin's solution of integral equations. Both the electric field integral equation (EFIE) and the magnetic field integral equation (MFIE) are used to obtain the scattered field from perfectly conducting objects. Our solution is first validated by comparing the radar-cross section (RCS) with the corresponding Mie series solution for conducting spheres. Next, we calculate the error convergence of the RCS from objects such as spheres and plates for several orders. In the case of objects with no analytical solution such as plates, over discretized solution is taken as the reference solution and the error results are then calculated.

A hybrid finite element method for near bodies of revolution (EM scattering)

Abstract: A genetic formulation for a hybrid finite element solution for three-dimensional electromagnetic scattering is given using the equivalent current approach. The major computational tasks involved in monostatic scattering calculations are analyzed and compared as a function of the method of implementing the near-field radiation condition, i.e. method of moments, model expansion, and body of revolution (BOR). A method utilizing a BOR formulation that addresses these computational issues is given. This BOR implementation utilizes Hermite cubic basis functions and a variable number of modes per basis function in order to achieve the greatest efficiency. The combined field integral equation formulation is used to eliminate nonphysical resonance of the mesh boundary. Examples are given showing the efficiency and accuracy of this BOR code by itself, and as part of this hybrid finite-element method. >