Application of bifocal concept to dual reflectarray configurations for multi-beam satellite antennas in Ka-band

This contribution describes the design of a multi-beam dual reflectarray antenna for operation in transmission in Ka-band (20 GHz). The bifocal design concept has been used to obtain an improved performance for the off-axis beams with respect to the single focused antenna. The required phase-shift distributions are initially obtained with the reflectarrays in parallel planes, and then adjusted to compensate the tilting of both reflectarrays in the final Cassegrain configuration. The simulated radiation patterns in the elevation and azimuth orthogonal planes have been calculated for the two beams generated by the focuses, and then the multi-beam performance of the antenna has been evaluated.