Rotman lens applications for the US Army: A review of history, present, and future

Array antennas that can simultaneously scan multiple beams are often desired for many radar and communications applications. One scanning approach controls the relative phase values at the array elements using microwave lens structures, achieving the desired progressive phase shifts through time delays. The Rotman lens is such a structure. It offers a cost-effective solution to electronic scanning of array antennas by serving as a broadband multiple-input multiple-output beam former network. Rotman lenses have found many uses in both military and commercial applications. This paper gives an overview of Rotman-lens applications from the military perspective. Ongoing efforts, future plans, and how the Rotman lens is foreseen as a feasible platform are also discussed.