A complete GTD analysis of rim loaded Cassegrain antennas

The radiation patterns of centered symmetric Cassegrain antennas are subjected to a complete numerical analysis, for a case in which the peripheral rims of both the reflector and the subreflector are assumed to be loaded by materials that are described in terms of surface impedances. So that it may be applicable to surface impedance boundary conditions, the geometrical theory of diffraction is generalized and in that form used in the computation of far-out sidelobes caused by diffraction processes. In addition, the physical optics approach is used in the main beam region.