Solving electromagnetic scattering from composite dielectric/metallic objects by EFIE-PMCHWT based domain decomposition method

Abstract

In order to deal with the challenge of modeling complex multilayer composite structures, various numerical methods have been proposed. For the multilayer dielectric/metallic composite objects, traditional method needs special test procedures at junctions to enforce the boundary conditions on the interfaces of different materials. The connect-region-modeling (CRM) method automatically enforces boundary conditions on the interfaces and avoids the special junctions testing procedures, but the CRM requires conformal meshes on interfaces to enforce the boundary condition. Recently, the integral equation (IE) based non-conformal, non-overlapping domain decomposition method (DDM) was proposed for non-penetrable object. The advantage of DDM lies in its flexible choice of integral equations based on the local property of a complex structure. For example, the electric and magnetic currents combined field integral equation (JMCFIE) is chosen for closed structures, while the impedance boundary condition (IBC) integral equation is used for objects with thin coatings. Different choices of integral equations result in variants of DDM. Existing integral equation based domain decomposition methods (DDMs) adopt combined field integral equations (CFIEs) as sub-domain governing equations, they are not suitable for modeling composite dielectric/metallic objects when open surfaces exist. To overcome this limitation for complicated dielectric/metallic composite objects, in this paper we developed an electric field integral equation (EFIE)-PMCHWT based DDM. The present DDM takes EFIE-PMCHWT as the governing equation for dielectric/metallic composite sub-domains. And, for closed sub-domains, CFIEs are adopted instead of EFIE. The transmission conditions (TCs) are enforced on the touching-face of adjacent sub-domains to ensure the continuity of fields. Compared to the connect-region-modeling (CRM) method, the proposed DDM has a better convergence property because of its locally diagonal-dominant system matrix. Furthermore, the TCs lead to a non-conformal discretization property, which greatly reduces the burden of mesh generation. Numerical results demonstrate the validity of the present method.