A 24-GHz CMOS Direct-Conversion Sub-Harmonic Downconverter

A 24 GHz sub-harmonic mixer based downconverter is presented. Fabricated in a 0.13 um CMOS process the downconverter includes a pre-amplifier and an IF buffer and consumes 13.6 mW with 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 DSB noise figure of 10 dB. The measured input referred 1 dB compression point is -12.7 dBm.