Compact Comparator for 2-D Monopulse Array Based on Novel Eight-Port Coupler

A compact comparator is proposed for two-dimensional (2-D) monopulse beamforming. A novel eight-port coupler is adopted as the fundamental component to generate the sum/difference ports for differential beams in two orthogonal planes. The proposed comparator has a double-layer microstrip configuration and without using T-junctions, vias, and steps on each layer. An example of 2 × 2 planar monopulse arrays working at 5.8GHz is built and simulated to verify and demonstrate the performance of 2-D sum/difference beamforming. Satisfying properties at matching, isolation, power division and phase distribution can be achieved in 10% fractional bandwidth.