A D-Band GCPW to SIW to Air-Filled RWG Cavity-Backed Transition for Integration of Communication System

In this paper, a compact D-band transition from ground coplanar waveguide to substrate integrated waveguide has been proposed and simulated. A pair of tapered slots is utilized in the transition from GCPW to SIW in order to realize high transmission performance. Meanwhile, the microwave coupled from SIW to air-filled RWG through an aperture and two inductive posts. It is worth mentioning that the metallic rectangular waveguide is embedded in a silicon wafer of
$500 \ \mu \mathbf{m}$
thickness. The cavity-backed structure of this transition is filled with ben-zocyclobutene (BCB), which is used for dielectric layer with low loss. The simulated results indicate that the transition has a relative bandwidth of 10.4 % from 138.8 GHz to 154 GHz for return loss better than 10 dB. The minimum insertion loss is 0.9 dB, which includes the loss of three parts of this transition.