A low-cost optical controlled phased-array antenna with optical true-time-delay generation

摘要

We have designed and demonstrated a low cost microwave-photonic phased-array antenna with a novel, simplified 16-channel optical true-time-delay array generator for microwave beamformign/steering. The true-time-delay array generator is built with simple optical path duplication architecture eliminating the need for optical switches, 1xN splitters, multiple lasers or Wavelength Division Multiplexing devices. Therefore, the cost is reduced by orders of magnitude as compared with other designs in the literature. To make a low cost demonstration, we have first fabricated the true-time-delay generator using free-space optics having mechanical displacemnt which can provide continuous time delays and power distribution for the array in the optical domain. A commercial 3 GHz laser transmitter and 16 photodetectors are used for optical-microwave link/transformation. The phased-array antenna has demonstrated a continuous scan/steering from -45?to 45?with reduced side lobes using a Dolph-Tschbyscheff array power distribution. As such, it provides an immediate solution, for the first time, to fabricate a realistic prototype photonic phased array antenna with a realistic price. We are also working on a long term solution which is to miniaturize the true-time-delay array generator by using optical MEMS technology and photonic bandgap structures so that our future true-time-delay array generator can be built in chip scale.