The Poggio-Miller-Chan-Harrington-Wu-Tsai (PM- CHWT) integral equation discretized with the method of mo- ments (MoM) in conjunction with the edge-based Rao-Wilton- Glisson (RWG) set is normally used in the electromagnetic scattering analysis of arbitrarily shaped penetrable structures. However, since the RWG basis functions impose the normal- current continuity across adjacent triangles arising in the surface mesh, the RWG-based implementations are only valid for confor- mal triangulations. In this paper, we introduce a nonconforming PMCHWT domain decomposition method for the scattering analysis of penetrable structures which is valid for conformal and nonconformal meshes. This scheme does not require the definition of artificial enclosing surfaces and auxiliary currents in the process of tearing the original domain. The transition of the electric and magnetic currents across adjacent sub-domains is imposed with the facet-based monopolar-RWG set together with a volumetric testing scheme over the tearing contour. The proposed method allows for the construction of an effective block- diagonal preconditioner for large and multi-scale problems.

Peer Reviewed