Analysis of reflector antennas including higher-order interactions

Abstract

An iterative hybrid method is developed to analyze a reflector antenna system operated at higher frequency bands. The analysis of a feed system is done by using a full-wave analysis technique and results in an initial secondary sources for the corresponding main reflector. Whereas, a geometrically simple but electrically large main reflector is treated with various HFATs (high-frequency asymptotic techniques). As the HFAT's solution is used to update the initial secondary sources of the full-wave solution, it is referred to as the first iteration step. Consequently, the iterative hybrid method combines those two solutions obtained from different regimes in such a manner that they are computed independently, yet all possible higher-order interactions between them are properly taken into account as the iteration step increases. The method utilizes the BIE (boundary integral equation) to terminate the FEM domain, e.g., the feed alone or the feed with the sub-reflector. The FEM/BIE is then hybridized with PO (physical optics), GTD (geometrical theory of diffraction) or PO+PTD (physical theory of diffraction) to treat the main reflector. The computational effort for this iterative method does not depend on the ratio of the focal length to the diameter of a reflector. This indicates that the technique will become highly efficient and accurate compared to any single full-wave analysis technique or HFAT alone when it is applied to analyze an electrically large reflector antenna system.