A Q-band monolithic balanced resistive HEMT mixer using CPW/slot-line balun

A Q-band balanced resistive high-electron-mobility transistor (HEMT) mixer has been developed for high-level integration of millimeter-wave receivers. The mixer consists of two AlGaAs/GaAs HEMTs, a CPW/slot-line LO (local oscillator) balun, and an active IF balun. This mixer can be easily integrated with the RF, LO, and IF HEMT amplifiers on one chip because it uses the HEMT as the mixing device. This mixer does not require backside and via-hole processes since it is realized with CPW (coplanar waveguide) circuitry. This unique feature increases the circuit yield and shortens the processing time. The mixer downconverts the 42-46 GHz RF to a 2.3-3.2 GHz IF. The conversion loss is less than 8 dB over the entire RF frequency range with a LO drive of 14 dBm. The minimum conversion loss is 4 dB from a RF at 43.0 GHz and a LO at 40.25 GHz. The Q-band mixer also achieves a 10.3 dBm output third-order intermodulation intercept point and a 1.5 dBm output 1 dB compression point.<>