Photonic true-time delay beamforming system for a phased array antenna receiver

In this paper we propose a phased array antenna receiver which relies on a photonic true time delay beamformer. The beamformer is based on a tunable optical delay line, which comprises a phase shifter for adjusting the power-coupling ratio between the arms of a Mach-Zehnder delay interferometer. The system can be integrated in a chip avoiding scalability problems of beamformers networks. The time delay between the arms of the interferometer can be adjusted allowing record ultra-fast switching times. The concept for N antenna elements is described and simulation results of the tunable optical delay lines show that the system provides true-time delay beamforming with negligible signal distortion for a moderate number of antenna elements.