Versatile facet-oriented discretization of the electric-field integral equation

Traditional method-of-moment implementations of the electric-field integral equation (EFIE) are based on sets of divergence-conforming basis functions, such as the loworder Rao-Wilton-Glisson (RWG) set, which arise from imposing normal continuity in the expanded current across the edges arising from the triangulation around the boundary surface. These schemes are edge-oriented and become well-suited for the analysis of conformal meshings, where pairs of adjacent triangles share common edges. However, they cannot be applied to nonconformal triangulations, arising from the interconnection of independent meshings, for example in the modular modelling of composite objects, because adjacent triangles may not have common matching edges. In this paper, we present several facetoriented implementations of the EFIE that allow the robust and versatile analysis of such objects. Two schemes arise from testing the fields over a set of tetrahedral or wedge elements attached to the boundary surface, inside the conductor. Another scheme, “tangential-normal”, derives from testing the fields over pairs of adjacent triangles such that one triangle matches a particular facet of the surface meshing and the other one is oriented inwards perpendicularly to the surface triangulation.