Improved accuracy in the scattering analysis of arbitrarily shaped ferromagnetic objects

Abstract

The electromagnetic scattering analysis of arbitrarily shaped ferromagnetic bodies is usually carried out with the Poggio-Miller-Chan-Harrington-Wu-Tsai (PMCHWT) integral equation. In the Method of Moments (MoM) discretization of the PMCHWT formulation, the RWG set is very often adopted in the expansion of the unknown traces of the total electromagnetic fields over the boundary surface of the target. The RWG-schemes are edge-based and become in general well- suited for the analysis of single targets meshed with conformal meshings, where adjacent triangles share common edges. However, their implementation for composite objects becomes elaborate around junctions, where several regions intersect. In this paper, we expand the electric and magnetic field traces over the boundary surface with the monopolar-RWG set, which stands for a facet-based scheme. Unlike the divergence-conforming RWG set, which imposes normal-continuity across edges, the monopolar-RWG set is nonconforming because a fully discontinuous transition across edges is established. This allows for the agile analysis of complex bodies or nonconformal meshes, with nonmatching edges between adjacent triangles. We show the improved RCS-accuracy for the monopolar-RWG discretization of the PMCHWT, with respect to traditional RWG-discretization, for an example of ferromagnetic object.