Advances in Microwave Photonic Beamforming for Phased-Array Antennas

Advances in microwave photonic phase shifters for beamforming in phased-array antennas are presented. This includes a grating based microwave photonic phase shifter structure, which features a simple configuration only requiring a single control to shift the RF signal phase, and which can be extended to obtain multiple phase shifts. It demonstrates a continuous phase shift capability with low amplitude variation and low phase deviation over a wideband microwave range. Also, an integrated silicon photonics on-chip phase shifter based on single all-pass micro-ring resonator is described. This is based optical single sideband modulation in conjunction with control of the separation between the laser wavelength and the resonance wavelength of the micro-ring to change the phase of the RF signal after photodetection. Experimental results have demonstrated a phase shifter with continuous phase tunability at microwave frequencies from 20 to 40 GHz. These microwave photonic phase shifters provide new capabilities for the realisation of high-performance phased arrays.