A three dimensional Gaussian Beam diffraction approach to analysis of reflector antennas

A 3D Gaussian Beam (GB) diffraction approach for reflector antenna analysis is presented. This method expands the input beam/field from the feed or FSS into a set of elementary Gaussian beams by using windowed Fourier transform (WFT). These Gaussian beams propagate to the reflector. Reflected beams are treated in a geometrical optics manner. Diffracted beams are treated with a full 3D Gaussian beam diffraction method. The diffraction of a general astigmatic Gaussian beam impinging arbitrarily close to the edge at an arbitrary orientation is considered. The diffracted field is expressed as a sum of diffracted Gaussian beams emerging from a discrete set of points and directions along the edge axis. The output field is a superposition of all reflected and diffracted Gaussian beams propagating to the next reflector, making the method modular and suitable for analysis of large multi-element quasi-optical systems. Case study demonstrated that the proposed 3D Diffraction Gaussian Beam Analysis (3D-DGBA) is accurate.