Patent ID: 7714776

Claim:
An antenna array comprising: a surface comprising a replicated pattern of conductive tracks, said tracks defining a plurality of ports, a plurality of radiative antennae, said antennae being located at ports distributed about said surface, a plurality of receiver, each receiver including a respective antenna; a plurality of reference transmitter paths, each transmitter path including a non-radiative impedance located at a respective port so that each reference transmitter is surrounded by a group of receivers and electrically coupled to said group of receiver antennae by said tracks, at least one antenna from at least one group of receivers belonging to one other group of receivers; and calibration circuitry including a controller associated with each reference transmitter, each said controller being arranged to transmit a calibration signal through an associated reference transmitter and to receive and store a received calibration signal from a selected receiver for said group of receivers coupled to said reference transmitter; each said controller being further arranged to receive and store a calibration signal from said selected receiver for said group of receivers coupled to said reference transmitter, said calibration circuitry farther including for each other receiver for said group of receivers, circuitry for adjusting the phase and amplitude of signals received by said receivers relative to said stored calibration signals for said selected receiver.