Research and design of a waveguide sum-difference comparator for monopulse radar applications

This paper presents the research and design results of a waveguide sum-difference comparator for monopulse radar applications. The proposed sum-difference comparator is designed to meet the requirements of wide bandwidth, low insertion loss, and high port isolation, while maintaining good amplitude and phase balance across the operating frequency band. Ku-band monopulse radar systems demand waveguide combining networks with high stability and low loss to ensure accurate generation of sum and difference signals. Conventional waveguide T-junction–based comparators are typically limited in bandwidth and exhibit insufficient port isolation, which can degrade monopulse tracking performance. In this work, a Ku-band 4×4 waveguide power combining and dividing network based on a hybrid configuration of H-plane and E-plane slot couplers is proposed for monopulse radar applications. The H-plane slot couplers are employed to achieve in-phase power combining, while the E-plane slot couplers provide phase inversion and enhanced port isolation. Full-wave electromagnetic simulations are carried out using the CST Studio Suite to optimize the geometrical parameters and ensure compliance with the design specifications. The proposed design offers a compact, robust, and high-power-handling solution suitable for Ku-band monopulse radar front-end processing systems.