Wideband Direction of Arrival Estimation using Monopulse in Rotman Lens Beamspace

In this paper, an efficient and responsive amplitude-based wideband Direction of Arrival (DoA) estimation approach using a multiple beam antenna setup is presented. The simultaneous spatial beams (beamspace) are generated using a Rotman lens as a true time delay network with an attached Uniform Linear Array (ULA) consisting of broadband Vivaldi antenna elements. The proposed processing scheme is divided into two major steps. In the first step a coarse power based direction finding on the Rotman lens beamports is done. In the second step an amplitude-based monopulse estimation is applied to corresponding adjacent Rotman lens beamports to get a higher resolution. This results in much lower computational load compared to classic phase dependent array processing algorithms like Capon or MUSIC which are not directly applicable for wideband DoA in contrast to our approach. The performance is evaluated with measurements performed in an anechoic chamber.