Contoured-beam Gregorian antenna with a reflectarray as subreflector. 2

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, the method of moments (MoM) for the flat reflectarray, and physical optics (PO) for the main parabolic reflector. The technique has been applied to the analysis of a shaped beam with DBS coverage requirements. The speaker describes the analysis technique and its validation, and the results for a shaped beam: using both the array as a feed of the reflector, and a subreflectarray.