Coherent optical beomforming techniques

Future phased array antennas will have stringent requirements in terms of performance, mass and power, which can be efficiently met by optoelectronic techniques. By employing coherent optical processing in guided-wave optical components, and with extensive use of optoelectronic integrated circuits, substantial reductions in mass and power are feasible in comparison with conventional beamformers. In a major study for European Space Agency, reductions of 30% and power reductions of 60% were seen to be feasible in a complex beamformer for a space-borne communications antenna, relative to a MMIC-based system with the same performance requirements. In order to verify the system concept, we designed and constructed a complete proof of concept model (PCM) offering both transmit and receive mode operation in the 12 GHz band. Detailed performance evaluation has been carried out, resulting in the first practical demonstration of the application of coherent optical techniques in an antenna beamformer. In this paper we discuss the optoelectronic beamforming concept, the application of this concept to a specific antenna and the design and construction of the proof of concept model.