Grid-robust Discretization of Integral Equations in the Electromagnetic Scattering Analysis of Homogeneous Targets with Geometric Singularities

The conventional method-of-moment schemes of discretization for the scattering analysis of homogeneous targets, perfectly conducting or dielectric, rely on edge-based basis functions. This restricts the modelling of the targets to conformal meshes, with all adjacent facets sharing one single edge. Prior to the electromagnetic analysis, edge-based schemes require the execution of edge search algorithms in order to establish the set of interior edges of the mesh. On the other hand, flaws in the mesh generation may give rise to an incomplete identification of the interior edges and a wrong modelling of the currents. Recently introduced facet-based schemes of discretization of surface integral equations, with volumetric testing, have exhibited improved accuracy in the analysis of targets with geometric singularities. Since facet-based schemes ignore by definition edges, they are better suited than the edge-based schemes for the robust analysis of slightly defective meshes, e.g. with unconnected vertices or misaligned edges.