Mixed-domain Galerkin expansions in scattering problems

Entire-domain Galerkin expansions provide a computationally efficient representation in method-of-moments (MM) solutions for electrically extended surfaces forming part of a separable coordinate geometry. For surfaces not conforming to such geometries, such as those with discontinuities, subdomain representations have been used. For many classes of scattering problems involving electrically large two-dimensional scatterers with localized discontinuities, a mixed-domain Galerkin expansion is shown to lead to a computationally efficient formulation. Electromagnetic-scattering solutions are developed for such configurations. Convergence of these solutions is illustrated with choices of mixed-domain expansions as a function of surface discontinuity. The computed results are given for both transverse magnetic (TM) and transverse electric (TE) polarization and are compared with published results