A Monopulse Rotman Lens Phased Array for Enhanced Angular Resolution

Abstract

A low cost monopulse phased array is described, which is based upon a Rotman lens and switched line phase shifting network. An amplitude comparison monopulse scheme is implemented, where the phased array is capable of scanning the sum and difference beams throughout a 60deg field of view. The sum beam directivity is better than 12 dB within a 6 GHz bandwidth at Ka band. Over 20 dB difference beam nulls were achieved throughout a 1 GHz bandwidth. The entire phase shifting circuit occupies a size of 62 mm by 62 mm, which is no larger than conventional Rotman lens circuitry.