A fast iterative physical optics (FIPO) algorithm based on now uniform polar grid interpolation

In this paper, a novel fast iterative physical optics (FIPO) algorithm is proposed for analysis of scattering front electrically large objects involving multiple reflections such as the case for open-ended cavities. At each iteration, the physical optics current induced on the surface of the scatterer produces a correction to the incident field, which in turn induces a correction to the physical optics current. The FIPO algorithm relies on fast field evaluation, which is achieved via domain decomposition of the scatterer surface and comprises two steps repeated for each subdomain. First, computation of the field is produced by currents residing within a subdomain over a sparse set of points surrounding the scatterer. Second, phase removal, interpolation, phase restoration, and aggregation of the field of the subdomain are integrated into the total field on the surface. The proposed approach can be extended to fast iterative solution of problems discretized via the method of moments. (C) 2002 Wiley Periodicals, Inc.