Mechanisms that contribute to the far-field polarization properties of phased-array antennas

The authors identify and quantify feed and phase shifter mechanisms for establishing the polarization properties of phased-array antennas. The polarization characteristics were measured for a small number of circularly polarized dual-mode ferrite phase shifters. These data were used in a computer simulation of 7000-element space-fed array to determine the impact of both feed-induced and phase-shifter-induced crosspolarization on the overall polarization performance of the array. It is shown that the array size, architecture, and components must be considered along with the element pattern when assessing the polarization characteristics of phased-array antennas. The polarization of large linearly polarized constrained-feed arrays can be determined primarily by the array element pattern. However, in the case of circularly polarized space-fed arrays using dual-mode phase shifters, the effects of the polarization characteristics of the phase shifter and feed must be included in the overall assessment of the array polarization.<>