Matrix methods for the analysis of polarization losses in antenna arrays

Abstract

An antenna array of N arbitrary geometry radiators is considered. In this connection it is assumed that the partial radiation patterns * of the array at no-load radiator inputs are known, as well as their orths b° and c° decomposition of the given orthogonal polarization basis *.

Two matrix methods are offered for analyzing of polarization losses in the antenna array. The first method uses the impedance approach where a multiport is assigned to the system of N radiators, the multiport inputs coincide with the real terminals of the radiators; this multiport is specified by the normalized impedance matrix z. The real part of this matrix can be decomposed into three components resistance loss matrix r_d and two matrices r^bb and r^cc, one of them describes the array radiation resistances for the main polarization and another - for the cross polarization. The second method is based upon the wave approach where 3N-port described by the scattering matrix S is assigned to the system of N radiators. The 3N ports of this multiport are split into three equal groups. One group corresponds to the real inputs of the radiators, and the rest two groups are the orthogonal channels in free space on the main and cross polarization waves. The formulas for calculating the antenna array scattering matrix and polarization loss factor for any polarization basis, and also the expressions allowing to jump from one polarization basis to another, are presented.

Both methods are illustrated with computation results.