The RF PRISM satellite concept applied to high resolution passive microwave imaging

RF PRISM is an innovative space antenna concept where an array is fed through a mesh of points on the antenna back with RF signals transmitted (or received) by another satellite called illuminator and typically offset by 100 km on the same orbit. Basically the Prism deviates, amplifies, and beam forms the signals passing through it and travelling between the illuminator and the Earth. Providing that incidences on the antenna plane of the speed vector and of the main Earth-sighting axis meet a specific relation (depending on design options, generally equality) the antenna deformation control or knowledge requirement is relaxed by a factor 10. Moreover there are no longer cables between the antenna panels. RF PRISM therefore enables deployment of a very large antenna in space. The illuminator satellite is not constrained by the illumination function (a few Watts and a 1m ² antenna), but just by the central payload function moved away from the satellite bearing the antenna. This can, in certain cases, be a microsatellite. Passive microwave imagery, usually so constrained by antenna size, should be among the applications. All the more so as here RF PRISM offers another advantage in that two satellites following each other allow for use of the VLBI technique to obtain along track resolution and thus reduce the antenna size constraint into the sole dimension enabling cross track resolution. The concept can also be applied to eavesdropping