A 3-D metal-direct-printed, low-cost, and light hexagonal waveguide Ka-band branch line coupler

A hexagonal waveguide branch line coupler suitable for manufacture by a 3-D printer is proposed in this study, and its design method is elucidated. The Ka-band coupler manufactured by a 3-D printer exhibits characteristics similar to those of a machined coupler, but its weight and cost is reduced by 40% and 66% respectively. Its effectiveness is also confirmed in this study.