Reflector Antenna Analysis Using the Complex Equivalent Length Concept: Reciprocity and Coupling Between Feeds

This work presents a procedure for analyzing multiply fed reflector antennas in both transmission and reception modes, by using the reflector antenna complex equivalent length (RA-CEL) concept. The RA-CEL is derived by combining the feed element complex equivalent length (FE-CEL) method with an equivalent current (EC) model on the reflector surface. This formulation, in terms of both electric and magnetic equivalent currents, is consistent with the reciprocity theorem. Its application to reflector antenna far-field pattern analysis, in both the transmission and reception modes, is presented. The proposed method accurately considers the mutual coupling among feeding array elements through the reflector surface, and its computational cost is substantially lower than required by a full-wave analysis. Some applications investigating the mutual coupling among feeding elements of reflector antennas are presented, and are compared with a reference solution given by the method of moments - physical optics hybrid method, and a numerical evaluation of the integral equation.