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.