A 24-GHz CMOS Passive Subharmonic Mixer/Downconverter for Zero-IF Applications

The design and implementation of a 24-GHz subharmonic-mixer-based downconverter based on a multiphase local oscillator (LO) is presented. Fabricated in a 0.13-mum CMOS process, the downconverter includes a pre-amplifier and an IF buffer and consumes 14.4 mW from a 1.6-V supply. The quadrature LO buffer consumes 15 mA at 1.2 V. The circuit includes a single-ended to differential phase splitter for the LO. The downconverter has a conversion gain of 3.2 dB and double-sideband noise figure of 10 dB. The measured input referred 1-dB compression point is -12.7 dBm. DC offsets were less than 2 mV.