Steering of an optically driven true-time delay phased-array antenna based on a broad-band coherent WDM architecture

Performance of a six-channel (delay) three-antenna element coherent optically driven phased-array antenna which transports true-time delays from the controller to the antenna site over 4.4 km of single-mode fiber (SMF) are presented. We demonstrate accurate true-time delay and beam steering from 0.8-1.5 GHz. Wide bandwidth intermediate frequency (IF) filters are used to minimize the phase-to-intensity noise, resulting in a single-channel signal-to-noise ratio (SNR) and dynamic range of 49 (dB-MHz) and 94 (dB-Hz)/sup 2/3/, respectively. Additionally, using up-conversion at the antenna site, true-time delays at frequencies up to 18.3 GHz are demonstrated.