Application of the generalized ray expansion (GRE) method to the electromagnetic scattering of waveguide covities

The analysis of high-frequency electromagnetic scattering by open-ended metallic waveguide cavities is useful for dealing with RCS problems. The most rigorous solution is obtained by modal analysis [1]-[3], but it is restricted to a small number of cavity shapes, such as those made of circular or rectangular sections. This problem may be addressed by using a Generalized Ray Expansion (GRE) method. Like other ray methods (GO/AI) [4]-[5], this approach allows to analyze arbitrarily shaped cavities, for which modes cannot be defined. Furthermore, better agreement with modal analysis is achieved. This communication concentrates on the application of the GRE approach. Some work is presented on the GRE technique in order to compare it with modal and ray methods, and some results are presented for two-dimensional and three dimensional problems [10].