Multilevel PO algorithm for non-uniform triangulations

Abstract

Fast physical optics (FPO) algorithm provides a speedup for computing the physical optics (PO) integral over complex bodies for a range of aspect angles and frequencies. In this paper, this algorithm is further developed in order to compute the scattered field from nonuniform triangulations of complex bodies. In the original "uniform" FPO algorithm, only the radiation patterns of the smallest subdomains in the bottom level are directly computed and the radiation patterns of the larger subdomains in the upper levels are computed via interpolation and aggregation. In this modified "nonuniform" algorithm, the radiation patterns of the larger triangles, which are too large to fit in the bottom-level subdomains, are directly computed and incorporated in the appropriate aggregation levels. It is also shown that, by applying different interpolation methods, accuracy of the FPO algorithm can be improved without any computational cost.