3-D scattering from a PEC target buried beneath a dielectric rough surface using a hybrid formulation and a fast solver

In this paper, an efficient hybrid approach to study the ElectroMagnetic (EM) scattering from a three-dimensional (3-D) Perfectly Electric Conducting (PEC) object buried under a two-dimensional (2-D) dielectric rough surface is developed. The electric and magnetic current densities on the rough surface are obtained through the current-based asymptotic Kirchhoff Approximation (KA) formulation whereas the electric current density on the buried object is rigorously determined by solving the Electric Field Integral Equation (EFIE) using the Galerkin's Method of Moments (MoM) with Rao-Wilton-Glisson (RWG) basis functions. The matrix equation arising from the MoM discretization of the hybrid KA-EFIE formulation is then efficiently solved by the iterative PILE (Propagation-Inside-Layer-Expansion) method combined with the algebraic Adaptive Cross Approximation (ACA). The current densities on the dielectric rough surface are thereafter used to handle the bistatic Normalized Radar Cross Section (NRCS) patterns.