Efficient Higher-Order Analysis of Electromagnetic Scattering of Objects in Half-Space by Domain Decomposition Method with a Hybrid Solver

Integral equation domain decomposition method (IE-DDM) with an efficient higher-order method for the analysis of electromagnetic scattering from arbitrary three-dimensional conducting objects in a half-space is conducted in this paper. The original objects are decomposed into several closed subdomains. Due to the flexibility of DDM, it allows different basis functions and fast solvers to be used in different subdomains based on the property of each subdomain. Here, the higher-order vector basis functions defined on curvilinear triangular patches are used in each subdomain with the flexibility of order selection, which significantly reduces the number of unknowns. Then a novel hybrid solver is introduced where the adaptive cross approximation (ACA) and the half-space multilevel fast multipole algorithm (HS-MLFMA) are integrated seamlessly in the framework of IE-DDM. The hybrid solver enhances the capability of IE-DDM and realizes efficient solution for objects above, below, or even straddling the interface of a half-space. Numerical results are presented to validate the efficiency and accuracy of this method.