MUCH RESEARCH IS FOCUSEDon the 75-to-110-GHz W-band. At 94 GHz, for example, low signal absorption creates an opportunity for applications like frequency-modulated-continuous-wave (FMCW) radar and image sensors. Yet such applications call for the creation of a high-performance device, circuit, and module. A 94-GHz monolithicmicrowave- integrated-circuit (MMIC) mixer module using 0.1-m gate-length metamorphic high-electron mobility transistors (HEMTs) has been developed by Dan An from Korea's Defense Agency for Technology and Quality with Sung- Chan Kim from Hanbat National University and Jin-Koo Rhee from Dongguk University.
The researchers proposed a modified resistive mixer with an RF amplifier. The mixer module was fabricated using a MMIC chip and coplanar-waveguide (CPW) transitions. At 94 GHz, the mixer chip and module showed conversion loss of 6.3 and 9.5 dB and LO-RF isolation of 24.8 and 30.4 dB, respectively. See "High-Performance W-band MMIC Mixer Module Using GaAs Metamorphic HEMT," Microwave And Optical Technology Letters, April 2010, p. 815.