Multi-band coaxial ring-focus antenna with co-located subreflectors

A multi-band ring focus antenna system includes a main reflector ( 408 ) that is operable at a plurality spectrally offset frequency bands. A first feed ( 301, 403 ) includes a first feed horn ( 301 ) and a first sub-reflector ( 403 ), which are positioned spaced apart from each other at respective locations along a boresight axis of the main reflector. The locations are selected so that the first feed horn and the first sub-reflector share a commonly located first phase center ( 401 ). A second feed ( 302, 404 ) designed for operation on a second RF frequency band includes a second feed horn ( 302 ) and a second sub-reflector ( 404 ), each positioned at a location along the boresight axis of the main reflector so that they share a commonly located second phase center.