Dual-band (Tx/Rx) multiple-beam reflector antenna using a frequency selective sub-reflector for Ka-band applications

This paper describes a dual-reflector antenna geometry combining multiple-feed-per-beam feed systems and a dichroic sub-reflector to produce a full dual-band (Tx/Rx) multiple beam coverage as typically required for broadband satellite missions. The proposed antenna configuration has several advantages as it requires only one main reflector aperture to produce the full coverage and makes use of two single band (Tx and Rx) multiple-feed-per-beam feed systems that are scaled versions of each other. Preliminary results are presented at antenna level assuming perfect dichroic screen and feed systems. These results confirm the potential of the proposed configuration for missions having strong satellite accommodation constraints and requiring a relatively small number of beams (typically less than 50 beams). This could particularly be of interest on board of small platforms or for secondary payloads. The dichroic sub-reflector being the critical point in this configuration, a preliminary feasibility study is also included, providing promising results.