A V-band high-linearity BiCMOS mixer with robust temperature tolerance

A high-linearity down mixer with outstanding robust temperature tolerance for V-band applications is proposed in this paper. The mixer’s temperature robustness has been greatly enhanced by employing a negative temperature-compensation circuit (NTC) and a positive temperature-compensation circuit (PTC) in the transconductance (gm) stage and intermediate frequency (IF) output buffer, respectively. Benefiting from the active balun with enhanced gm and emitter negative feedback technique, the linearity of the mixer has been significantly improved. For verification, a double-balanced V-band mixer is designed and implemented in a 130 nm SiGe BiCMOS process. Measured over the local oscillator (LO) bandwidth from 57 GHz to 63 GHz, the mixer demonstrates a peak conversion gain (CG) of −0.5 dB, a minimal noise figure (NF) of 11.5 dB, and an input 1 dB compression point (IP1 dB) of 4.8 dBm under an LO power of −3 dBm. Furthermore, the measurements of CG, NF, and IP1 dB exhibit commendable consistency within the temperature range of −55 °C to 85 °C, with fluctuations of less than 0.8 dB, 1 dB, and 1.2 dBm, respectively. From 57 GHz to 63 GHz, the measured LO-to-radio frequency (RF) isolation is better than 46 dB, the measured return loss at the RF port is > 29 dB, and at the LO port it exceeds 12 dB. With a 2.5 V supply voltage, the mixer power consumption is 15.75 mW, 18.5 mW, and 21 mW at temperatures of −55 °C, 25 °C, and 85 °C, respectively. Moreover, the mixer chip occupies a total silicon area of 0.56 mm2 including all testing pads.