GENERALIZED RAY EXPANSION WITH ELLIPTIC RAY TUBES IN HYBRID ANALYSIS OF EM SCATTERING BY OPEN CAVITIES

A hybrid analysis of the electromagnetic scattering by an open cavity containing an interior obstacle when it is illuminated by an external source is presented so that it is valid for high frequencies. This hyb rid approach breaks down the problem into three basic parts which can be analyzed separately, via methods best suited for each part, and the se separate solutions are then combined systematically via generalized reciprocity relations to obtain the total solution. The three separat e analyses deal with the scattering by the open end being illuminated, the wave propagation within the cavity, and the scattering by the int erior obstacle. The propagation region analysis is based on the use of the generalized ray expansion that employs a new elliptic ray tube ba sis set which makes this expansion far more efficient in that it requi res significantly fewer number of these than is possible with conventi onal ray tubes. Numerical results illustrating the utility of this hyb rid approach are presented.