Patent ID: 7834807

Claim:
A retro-directive antenna terminal comprising: an antenna reflector adapted to transmit and receive radio-frequency signals to and from at least one satellite; a feed array comprising at least two feed elements situated near a focus of the antenna reflector; an input section including a receive-side radio-frequency processor configured to generate a spatial receive-side Fourier transform (FT) of the radio-frequency signals received from the at least one satellite; a direction-of-arrival (DOA) processor adapted to measure a phase profile of the signals received from the at least one satellite after application of the receive-side FT; a digital-beam-forming (DBF) processor adapted to calculate beam weight vectors (BWVs) corresponding to the phase profile and to apply them to a transmit signal; and a transmit section including a transmit-side radio-frequency processor configured to generate a spatial transmit-side FT of the transmit signal and to apply the transmit signal to the feed array after application of the transmit-side FT; wherein, by applying the BWVs to the transmit signal and generating the transmit-side FT, the transmit section produces a signal radiated from the feed array that illuminates the antenna reflector to produce a beam that is directed back along a same direction as the radio-frequency signals received from the at least one satellite.