Reflectarray Design for Satellite Applications with Very Low Cross-Polarization Requirements

Abstract

Modern satellite applications for communications require a high polarization purity, usually with parameters such as the crosspolar discrimination (XPD) larger than 33dB. To achieve these values, some form of cross-polarization performance optimization must be carried out. The usual approach is to minimize the crosspolar component of the far field with regard to the copolar pattern in the region of interest. However, this generates suboptimal results since the figure of merit for cross-polarization performance, i.e. the XPD, is optimized indirectly. Thus, it is proposed to directly optimize the figure of merit to considerably improve the polarization purity of reflectarray antennas for satellite applications. For that purpose, the generalized Intersection Approach algorithm is used in a large reflectarray for a contoured beam application with European coverage. It is shown that directly optimizing the cross-polarization figure of merit provides better results than the usual approach of minimizing the crosspolar pattern.