Fast Algorithm of Arbitrary Beam Propagation Based on Adaptive Elliptical Gaussian Beam Decomposition

An algorithm for arbitrary electromagnetic (EM) beam propagation is proposed and well demonstrated in this paper. The essential idea of this algorithm is to decompose arbitrary beam into a small number of elliptical Gaussian beams, which is similar but different from existing diffracted Gaussian beam analysis (DGBA) based on Gabor expansion. The proposed algorithm utilizing adaptive Gaussian beam matching method is much more efficient than regular decomposition strategy by Gabor expansion. Beam propagation is then calculated by these elliptical Gaussian beams' superposed analytical results, with accuracy comparable with physical optics (PO) theory. This fast algorithm can be suitable for analyzing beam propagation in electrically-large systems, such as reflector antennas and quasi-optical (QO) transforming systems.