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(g_(m))stage and intermediate frequency(IF)output buffer,respectively.Benefiting from the active balun with enhanced g_(m)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(IP_(1 dB))of 4.8 dBm under an LO power of−3 dBm.Furthermore,the measurements of CG,NF,and IP_(1 dB)exhibit commendable consistency within the temperature range of−55℃to 85℃,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℃,25℃,and 85℃,respectively.Moreover,the mixer chip occupies a total silicon area of 0.56 mm2 including all testing pads.
