60 GHz CMOS downconversion mixer with 15.46 dB gain and 64.7 dB LO-RF isolation

A 60 GHz double-balanced mixer for direct downconversion using standard 90 nm CMOS technology is reported. The downconversion mixer comprises a double-balanced Gilbert cell with a current-reused RF single-to-differential converter for conversion gain (CG) enhancement, a Marchand balun for converting the single LO input signal to a differential signal, and a baseband amplifier. The mixer consumes 17 mW and achieves a low noise figure of 12.8 dB at 60 GHz. In addition, the mixer achieves excellent LO-RF isolation of 64.7 dB, LO-IF isolation of 51.5 dB, and RF-IF isolation of 59.5 dB at an RF of 60 GHz and LO of 59.9 GHz. At IF of 0.1 GHz, the mixer achieves maximum CG of 15.46 dB at an RF of 62 GHz, and CG of 14.7 dB at an RF of 60 GHz, which are believed to be the best CG results ever reported for a 60 GHz active CMOS downconversion mixer.