SiC Substrate-Integrated Waveguides for High-Power Monolithic Integrated Circuits Above 110 GHz

Substrate-integrated waveguides (SIWs) of different geometry are designed, fabricated, and measured on a SiC wafer, along with SIW-based resonators, SIW-based filters, grounded coplanar waveguides (GCPWs), GCPW-SIW transitions, and calibration structures. Two-tier calibration is used to extract the intrinsic SIW characteristics from GCPW-probed scattering parameters. The resulted D-band (110–170 GHz) SIWs exhibit a record low insertion loss of 0.22 ± 0.04 dB/mm, which is four times better than that of the GCPWs. A 3-pole filter exhibits a 1.0-dB insertion loss and a 25-dB return loss at 135 GHz, which represents the state of the art of SiC SIW filters and is order-of-magnitude better than Si on-chip filters. These results show the promise of SIWs for integrating HEMTs, filters, antennas, and other circuit elements on the same SiC chip.