A Hybrid Method for Analyzing Scattering from PEC Bodies Straddling a Half-Space Interface

In this letter, a novel hybrid method is proposed to efficiently analyze the electromagnetic (EM) scattering from arbitrarily shaped, perfect electrically conducting (PEC) bodies that penetrate the interface of a half-space. Due to different integrands involved in the reflection- and transmission-type Green's functions, a partition scheme is introduced where the adaptive cross approximation (ACA) and the multilevel fast multipole algorithm (MLFMA) are integrated seamlessly. In this scheme, different fast solvers are invoked automatically to achieve an optimal efficiency. The reconstruction of the Green's function via an image-based translational addition theorem is first investigated, and the empirical partitioning parameters are suggested. The performance of this hybrid method is then examined via two examples, including a benchmark target and a more realistic scenario in the near-surface scattering.