Numerical Simulation of electromagnetic scattering induced by an overfilled cavity in the ground plane

A finite element method (FEM) is implemented to analyze the scattering of a plane wave incident on a two-dimensional (2-D) overfilled cavity embedded in the infinite ground plane. The algorithm is based on a variational formulation where an artificial boundary condition is introduced on a hemisphere enclosing the cavity that couples the fields from the infinite exterior domain to those inside. Since the problem is solved exactly in the exterior domain, the radar cross section (RCS) can be computed efficiently. Our numerical solutions compare well with existing results. The perfect link over the artificial boundary between the FEM approximation in the interior and analytical solution in the exterior indicates the reliability of the method. A convergence analysis is also performed.