The first demonstration of an optically steered microwave phased array antenna using true-time-delay

The concept of true-time-delay steering for phased array antennas and its advantage over phase shifters in broadband applications are described with particular emphasis on the potential advantages offered by fiber-optic delay lines. The system architecture of the phased array antenna and the design and performance of the fiber-optic time-shifter networks in the antenna are described. The radiation patterns of the phased array antenna at L and X bands are presented. Using semiconductor laser switching to implement the delay times, the absence of beam squint in the antenna pattern and its frequency was switched from L to X band is demonstrated