On the Volume-Surface Integral Equation for Scattering From Arbitrary Shaped Composite PEC and inhomogeneous Bi-Isotropic Objects

A new generalized volume-surface integral equation, volume integral equation-combined field integral equation (VIE-CFIE), is proposed to analyze the electromagnetic (EM) scattering from composite objects comprised of both perfect electric conductor (PEC) and inhomogeneous bi-isotropic material. By discretizing the objects using triangular and tetrahedral cells on which the commonly used Rao-Wilton-Glisson (RWG) and Schaubert-Wilton-Glisson (SWG) basis functions are respectively defined, the matrix equation is derived using the method of moments (MoM) and the Galerkin's testing. Furthermore, the continuity condition (CC) of electric flux is explicitly enforced on the PEC and bi-isotropy interfaces. In this way, the number of volumetric unknowns is reduced based on the same set of meshes, particularly for the thin coated PEC objects. A convenient way to embed the CC into the context of MoM solution is provided in detail. Several numerical results of EM scattering from coated PEC objects are shown to illustrate the accuracy and efficiency of the proposed method.