Exact complex source point beam expansion of electromagnetic fields from arbitrary closed surfaces

In this paper, a relatively simple, exact method is developed to expand any arbitrary and fully vector EM field into a continuum of CSP beams. In practice, the continuum must be appropriately discretized to obtain a convergent sum of CSP beams. Furthermore, the natural windowing property of the beam function can be advantageously used to truncate this beam set since only a small number of beams remain significant at a given observation point. Hence, this CSP beam expansion approach can be potentially very useful for solving a variety of EM problems including radiation in the presence of radomes, reflector systems, etc., radiation from curved apertures and the near field to far field transformation in near field measurements.