Equivalence of Physical Optics and Aperture Field Integration Method in the Full Pattern Analysis of Reflector Antennas

Masayuki OODO  Makoto ANDO  

IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.8   pp.1152-1159
Publication Date: 1996/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwave and Millimeter Wave Technology
physical opties. aperture field integration method,  equivalent surface currents,  diffiaction coefficients,  

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Physical optics(PO) and the aperture field integration method (AFIM) give accurate and similar field patterns near the first few sidelobes of reflector antennas. It is widely accepted that the use of AFIM is restricted to norrower angles than PO. In this paper, uniform equivalent edge currents of PO and AFIM are compared analytically and their equivalence in high frequency in discussed. It is asymptotically verified that the patterns by AFIM are almost identical to PO fields in the full 360angular region, provided that AFIM uses the equivalent surface currents consisting of two components, that is, the geometrical optics(GO) reflected fields from the reflector and the incident fields from the feed source, the latter of which are often neglected. Slightly weaker equivalence is predicted for cross polarization patterns. Numerical comparison of PO and AFIM confirms all these results, the equivalence holds not only for large but also for a very small refiector of the order of one wavelength diameter.