Fast analysis of electromagnetic radiation/scattering from large reflector antennas with tapered impedance surfaces by a hybrid scheme of Gaussian beam and physical optics techniques

Relatively efficient Gaussian beam (GB) techniques (Chou, H.-T. et al., IEEE Trans. Antennas and Propag., vol.49, no.6, 2001) have been developed to accelerate the physical optics (PO) analysis (Rahmat-Samii, Y. and Tulintseff, A.N., IEEE Trans. Antennas and Propag., vol.41, no.4, p.476-87, 1993) of large reflectors of a perfectly conducting surface with smooth edge boundaries. The paper proposes a hybrid scheme combining GB and PO approaches to treat more general reflector problems, where the reflector can be surfaces with tapered impedance and irregular edge boundaries. In this hybrid scheme, the reflecting surface is decomposed into two portions that can be treated efficiently by the GB approach and PO, respectively. The interior portion with uniformly distributed impedance and smooth truncation boundaries can be well treated by the GB techniques of Chou et al. On the other hand, the exterior portion of the reflecting surface, where tapered impedance and irregular edge boundaries occur, can be treated utilizing the numerical integration of the regular PO approach. In most practical applications, the exterior portion is sufficiently small so that overall efficiency and accuracy can be well retained.