A novel elliptical spot beam antenna with beam reconfiguration capability

A high efficiency, multifunctional spot beam antenna, operating in the transmit/receive frequency band (10.95 GHz-14.5 GHz) has been developed within an INTELSAT R&D contract. The antenna belongs to the dual Gregorian offset reflector family and is capable of providing an elliptical beam with a major axis which can be continuously oriented by a simple rotation of the subreflector. Furthermore, the antenna allows a widening of the axes (zooming effect) and a varying of the ratio between the axes of the elliptical beam (beam shaping) for any orientation of the ellipse. This type of reconfigurability is obtained by adding another degree of freedom, that is, main reflector translation approximately along the offset exit. As an extreme case, a nearly circular beam has been created.