Continuously variable true time delay optical feeder for phased array antenna employing chirped fiber gratings

In this paper we propose and demonstrate a novel approach of true-time delay (TTD) optical feeder for phased-array antennas. A continuously variable TTD is achieved by employing tunable lasers and a wide bandwidth chirped fiber grating as dispersive element. The results show that a very high resolution performance (equivalent to a 6 bit microwave phase shifter) is obtained for a L-band phased-array antenna employing narrow tuning bandwidth lasers with a wavelength stability of 0.005 nm and a 4 nm bandwidth chirped grating with dispersion 835 ps/nm