A 75-85 GHz DOWN-CONVERSION MIXER WITH INTEGRATED MARCHAND BALUNS IN 90 nm CMOS WITH EXCELLENT MATCHING AND PORT-TO-PORT ISOLATION FOR AUTOMOTIVE RADARS

摘要

A 75-85 GHz double-balanced down-conversion mixer for automotive radars using standard 90 nm CMOS technology is reported. The down-conversion mixer comprises a double-balanced Gilbert cell with inductive source-degeneration RF transconductance stage for RF-port input matching bandwidth and conversion gain (CG) enhancement, a Marchand balun for converting the single RF input signal to differential signal, a Marchand balun for converting the single LO input signal to differential signal, and a baseband amplifier. The mixer consumes 13 mW and achieves excellent RF-port input reflection coefficient of -13.1 to -19.4 dB and LO-port input reflection coefficient of -9.1 to -11.8 dB for frequencies of 75-85 GHz. In addition, for frequencies of 75-85 GHz, the mixer achieves CG of -1 to 1.5 dB, LO-RF isolation of 43.5-49.2 dB, LO-IF isolation of 56.5-64.5 dB and RF-IF isolation of 35.9-39.4 dB, one of the best CG and port-to-port isolation results ever reported for a CMOS down-conversion mixer with operation frequency around 80 GHz. Furthermore, the mixer achieves an excellent input third-order intercept point of 2.7 dBm at 79 GHz. These results demonstrate the proposed down-conversion mixer architecture is promising for W-band transceivers. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:73-80, 2015