A hybrid technique for combining moment methods with the geometrical theory of diffraction

A technique for combining moment methods with the geometrical theory of diffraction is presented, which permits the application of the method of moments to a larger class of problems. The fundamental idea used to develop the hybrid technique is to modify the usual impedance matrix that characterizes, for example, a wire antenna so that a metallic body or discontinuity on that body is properly accounted for. It is shown that, in general, it is possible to modify the impedance matrix for any basis and/or weighting functions if the correct modification to the impedance matrix element can be computed. The modification is readily accomplished using the geometrical theory of diffraction and/or geometrical optics.