Space Exploration Initiative multibeam antenna study

A multibeam antenna which will be based on a Mars orbiting satellite has been proposed for the Space Exploration Initiative. This antenna would be used for a variety of purposes; besides communicating with fixed bases, the antenna would simultaneously need to communicate with mobile ground terminals mounted on vehicles or robots. Six basic antenna designs are presented, with additional variations on the basic designs considered. The first three designs are reflector antennas and the last three are phased array antennas. Some of the conclusions drawn from this study are given. For reflector antennas with array feeds, the feed array requires about 450 to 550 feed elements; a very long f/D system is needed to reduce scan loss for wide angle scan; cluster feed can be used to improve scan performance at the price of more complexity in the beam forming network; and multiple reflectors do not appear to be a viable candidate for meeting the present requirements due to blockage problems.<>