Terahertz broadband ridge gap waveguide to microstrip line transition structure

This paper presents a broadband gap-waveguide to microstrip line transition structure operating from 110 GHz to 270 GHz. The microstrip line is in the center of the ridge gap waveguide, and it can integrate with other circuits in the waveguide easily. Based on electromagnetic coupling, the designed structure converts the electromagnetic field from the ridge gap waveguide to the microstrip line. The back-to-back transition structure simulation result shows that the insertion loss is below 1 dB, and the return loss is above 10 dB in the working bandwidth. This structure reaches an 84% relative bandwidth in terahertz band.