Multi-branch Waveguide Coupler for 400 GHz Broadband

This paper explores the design and analysis of a multi-branch waveguide coupler for achieving broadband performance at 400 GHz. The proposed design utilizes a free-standing E-plane quadrature hybrid coupler and a series of hybrid T-junctions in a 4-branch layout, resulting in a high return loss and low insertion loss over a broad frequency range. The design method and simulation results are presented in detail.