TE20 Mode Differential Waveguide Directional Coupler and Wideband Balun by 3-D Printing

A 3D printed differential waveguide coupler utilizing TE20 mode is reported in this paper. It exhibits a 43% bandwidth operating from 13 to 20.3 GHz with a coupling magnitude of 3dB and variations of 0.6 dB. The device expands on existing coupling techniques and utilizes a novel 70% bandwidth ultra-wideband waveguide balun designed to produce the higher-order mode and facilitate measurement. The overall device possesses differential waveguide ports while offering comparable performance to typical fundamental mode waveguide directional couplers.