A novel design procedure for minimum rf phase error in optical ring resonator-based integrated optical beamformers for phased array antennas

We present a novel design procedure for optical ring resonator (ORR)-based integrated optical beam forming networks (OBFN) for microwave phased array antenna applications. Given the system specifications of minimum RF signal bandwidth (2.05 GHz), propagation loss in the optical waveguide (0.2 dB/cm) and maximum phase error allowed in band (π/16), the method is used to determine the number of ORRs required in each delay unit for minimum complexity and, in turn, minimum footprint in the realized chip. The effects of the RF phase errors obtained with the described procedure are also analyzed. The result shows negligible degradation in the array radiation pattern when imposing a maximum phase error of π/16 or lower.