Development of optical-RF transmitter modules for an optically addressed 2–40-GHz phased array

The architecture of an optically addressed ultra-wideband (2-40 GHz) phased array, based on microwave photonic down-conversion techniques, is described. For such a phased array, the transmitter module consists of an ultra-wideband antenna, photodiode, and power amplifier. A metamaterial-loaded Vivaldi antenna having a tailored, broad, flat-top radiation pattern and a broad impedance bandwidth is presented. Additionally, the integration of photodiodes and power amplifiers capable of operation at a high speed with broad bandwidth is described. The measured results indicate that the module can achieve the high level of performance necessary to meet the desired requirements of the phased array.