A Parabolic Reflectarray for a Bandwidth Improved Contoured Beam Coverage

A two-layer reflectarray made of varying-sized patches on a parabolic surface is proposed in this paper to enlarge the bandwidth for shaped-beam antennas in telecommunication missions. The beam is focused by the parabolic surface, while the phasing on the reflectarray is used to generate the required contoured beam. A technique for the analysis and design of the parabolic configuration is presented, in which the dimensions of the patches are optimised to produce the required phase-shift, by iteratively using an analysis routine based on the method of moments (MoM) assuming local periodicity. The proposed technique has been used to design a 1.5-metre reflectarray for a South American coverage. The results show a significant improvement in bandwidth with respect to a flat reflectarray, at the cost of a higher cross-polar radiation produced by the parabolic surface.