A hybrid method for the solution of the electromagnetic scattering by an inhomogeneously filled trough or slit in a thick conducting screen

A hybrid method that combines the method of moments (MOM) and the finite element method (FEM) is presented. The technique´s power consists in the fact that the FEM matrix need only be filled and factored once. Subsequently, the aperture fields are then solved for when the cavity is perturbed by the equivalent aperture currents, and are matched to the exterior region. The exterior problem is then solved using the MOM. The MOM solution requires only the filling and factoring of a small dense matrix, providing a means to solve for the aperture currents for any number of incident fields. Numerical results for various problems are presented.<>