Design of 4-Beam Orthogonal Switching Matrices Using Couplers With Smaller Coupling Ratio

This manuscript presents designs of one-dimensional four-beam switching matrices using directional couplers with smaller coupling ratios. By eliminating crossovers from the conventional configuration, the design shortens the overall matrix length and reduces output imbalance. The structure is based on post-wall waveguides on a PTFE substrate with symmetrically arranged phase shifters. The simulation results show that one of the proposed configurations achieves wider bandwidth operation, with improved performance particularly in the lower frequency range, both in reflection and transmission coefficients.