3-D 94 GHz single balanced mixer for low conversion loss with ring coupler by DAML

A 94 GHz single balanced mixer in 3-dimension was successfully fabricated. The GaAs-based low loss transmission lines, dielectric-supported air-gapped microstrip lines (DAMLs), have been developed using surface micromachining technology, and the DAML-based hybrid ring coupler is successively fabricated. We have developed the high-performance 94 GHz single balanced active mixer using hybrid ring coupler with 70 nm gate length MHEMT. The mixer showed the conversion loss of 2.5 dB ~ 2.8 dB and isolation characteristics less than -30 dB, in the range of 93.65 GHz ~ 94.25 GHz. These results are the best performances demonstrated from a 94 GHz single balanced mixer utilizing GaAs-based HEMTs in terms of conversion loss as well as isolation characteristics.