Contoured-Beam Gregorian Antenna with a Reflectarray as Subreflector

In this contribution, a reflectarray is proposed as subreflector in a dual-reflector configuration to produce a contoured beam for DBS applications. The beam shaping is obtained by adjusting the phase on the reflectarray elements. In order to analyse the antenna, a modular technique has been developed so that the most appropriate analysis method is used for each element of the structure: full-wave simulation or measurements for the feed-horn, Moments Method (MoM) for the flat reflectarray and Physical Optics (PO) for the main parabolic reflector. The technique has been applied to the analysis of two cases: a focussed pencil beam and a shaped beam with DBS coverage requirements.