Patent ID: 7209079

Claim:
Beam steering apparatus comprising: an antenna array having a plurality of antenna elements, the antenna elements being spatially arranged with respect to one another and being operable to receive signals; signal modulating means for modulating signals received by said antenna elements onto different respective optical carriers, said signal modulating means comprising a plurality of optical modulators, each of which is associated with a different one of the antenna elements; delay means for applying an amount of delay to modulated optical signals passing therethrough in respect of at least one of the antenna elements; demultiplexing means for separating the modulated optical carriers within an optical signal output by the delay means; demodulating means for demodulating the signal received by each antenna element from the respective separated modulated optical carrier; and combining means for combining the demodulated received signals output by the demodulating means, wherein the delay means comprises: a plurality of first delay units, each of which is associated with a different one of the antenna elements and is operable to apply selectively either a first amount of delay or a second amount of delay to the respective modulated optical signal passing therethrough; and a plurality of second delay units, each of which is linked in series to at least one of the first delay units and is operable to apply selectively either a third amount of delay or a fourth amount of delay to modulated optical signals passing therethrough, and wherein at least one of said second delay units is connected in series to at least two of the first delay units.