Design of Bifocal Dual Reflectarray Antennas in Ka-band to Generate a Multi-Spot Coverage from Geostationary Satellites

This contribution studies the use of bifocal dual reflectarray antennas to provide multi-spot coverage from a geostationary satellite operating in Ka-band. A general 3D bifocal technique has been applied to design a multi-beam dual reflectarray antenna in an offset compact-range configuration, considering three different degrees of beam spacing compression (high, low and no compression) with respect to the equivalent monofocal antenna. The results of the design (bifocal phase distributions, radiation patterns, etc.) have been compared for the three cases under study. The use of suitable reflectarray cells will allow to produce independent beams in each polarization (two beams per feed), so that the bifocal antenna will provide adjacent beams in orthogonal polarizations with 0.56° angular spacing.