A Detector-Switched GaAs Monolithic Time-Delay Network for Microwave Phased Arrays at L and X Band

Abstract

Recently, there has been much interest in the development of photonic techniques for steering microwave phased array radar over multiple microwave bands. In these optically controlled phased array antennas, guided lightwave is used as a carrier for distributing and delaying the microwave signals that drive and “phase-up” the antenna radiation elements. A first demonstration of the above concept was reported by Ng et al1 using fiber-delay-lines. As described in Ref. 1, these optically controlled phased array antennas displayed instantaneous bandwidths of almost one frequency decade — from 2 to 9 GHz — which was previously unattainable. In this paper, we will report on the demonstration of a GaAs monolithic time-delay network (Fig. 1) for steering phased arrays from L (1-2.6 GHz) to X (8-12 GHz) band. Specifically, the monolithic time-delay network integrates the delay lines (curved GaAlAs/GaAs rib-waveguides) and MSM detectors that serve as optoelectronic switches on a GaAs substrate.