Micromachined rectangular coaxial line and cavity resonator for 77 GHz applications using SU8 photoresist

Thick SU8 photoresist technique is used to fabricate two millimetre-wave components. Firstly, an air-filled rectangular coaxial line operating from 55 to 87 GHz is fabricated and tested, and an insertion loss of 0.8dB and return loss of better than −15dB was obtained. The overall measured responses agree well with full-wave simulation results. Secondly, a cavity resonator operating at 77GHz is reported. An unloaded Q value of 569 was obtained, which is, to our knowledge, one of the best reported so far in a similar structure.