Surface Micromachined Integrable High Efficiency Ridge Gap Waveguide Bandpass Filter for G-Band 6G Applications

This paper presents a third-order band pass filter (BPF) ridge gap waveguide (RGWG) fabricated utilizing the combination of SU-8 polymer and a photolithography and subsequent metallization process. The RGWG device is designed, simulated, and fabricated to operate in the G-band (110 - 300 GHz) frequency range. With a center frequency of 167 GHz, the fabricated devices have average surface roughness and fabrication tolerances less than 100 nm and 25 tim in all three dimensions, respectively, which are significantly smaller than those of computer numerically controlled (CNC) fabricated devices, e.g. greater than 300nm and 50 tim respectively. The micromachined SU-8 based devices in simulation show 0.87 dB insertion loss at a center frequency of 167 GHz with a 7.5% fractional bandwidth (FBW). Realized the BPF-RGWG device has potential for use in high-frequency applications such as satellite communication and millimeter-wave imaging systems.