A CMOS passive mixer for direct-conversion receivers

In this work, the design of a new frequency doubler passive subharmonic mixer circuit for low-power and low-cost biomedical devices is presented using CMOS 0.13 mum UMC technology. This circuit operates in a quadrature double-balanced mode and required octet-phases. Included in the design is a circuit that generates an octet-phase LO signals from a differential input, an output LNA buffer and a resistive source degeneration intermedeiate frequency (IF) buffer. The whole circuits consume 1.8 mA from a 1.2-V supply. The mixer with the included circuits achieves 21-dB conversion gain, 11-dB noise figure, 12-dBm IIP3 and -11.2-dBm 1-dB compression point.