Substrate Integrated Waveguide Structural Transmission Line and Filter on Silicon Carbide Substrate

Substrate integrated waveguide (SIW) structural transmission line (TL) and filter are designed and fabricated on semi-insulating silicon carbide (SiC) substrates for operation at the low end of H-band. The via-holes as the sidewall of SIW are achieved by using a fine dry-etching technique, where the radius and the via-via distance of the via-hole row are determined according to the transmission characteristics and the fabrication process. Measurements show that SIW-based TLs have the attenuation constant of as low as 0.45 dB/mm at 220 GHz, a third of that for TLs on grounded coplanar waveguide, and SIW-structural filters have the minimum insertion loss of <;1 dB at the center frequency of 183 GHz with a bandwidth of 5.3 %. It illustrates the availability of passive device fabrications on SiC substrate, and paves the way for the forthcoming terahertz monolithic integrated circuits based on wide bandgap semiconductors.