Coherent optical techniques in antenna beamforming for satellite communications

In order to meet the needs of business telecommunications traffic, satellite antennas will be required which can form multiple spot beams and permit extensive frequency reuse, implying stringent requirements with respect to control of beam shape and sidelobe suppression, combined in many cases with rapid reconfiguration and beam hopping or scanning. It is likely that the extensive use of optical technology in critical signal distribution and control functions will provide the key to successful use of active phased array antennas in space. The authors discuss the role of optics in providing not only T/R module interconnection but also transmit and receive beamforming functions for a typical future communications satellite antenna. They emphasize the use of coherent optical transmission and processing techniques, which are seen to offer significant advantages in terms of performance and flexibility