Dual-Frequency Reflectarray Cell to Provide Opposite Phase Shift in Dual Circular Polarization With Application in Multibeam Satellite Antennas

A new reflectarray cell is proposed to simultaneously provide opposite phase shifts between orthogonal circular polarizations at two frequencies (19.7 and 29.5 GHz) by applying a variable rotation technique independently at each frequency. The reflectarray cell, which consists of two dielectric layers with two levels of printed elements (dipoles and arcs), has been characterized for both circular and linear polarizations at each frequency. Apart from the implementation of the variable rotation technique at each frequency, the reflectarray cell provides an additional phase adjustment at the higher frequency, which can be used to shape the beam. This concept applied to multiple spot satellites in Ka-band will allow to produce two adjacent beams per feed in orthogonal circular polarizations at transmission and reception frequency bands.