Low Phase Noise and High Conversion Gain Oscillator Mixer Constructed with a 0.18- m CMOS Technology

This paper presents a compact down-conversion oscillator mixer fabricated with a 0.18-m CMOS technology. The oscillator mixer consists of a conventional nMOS differential coupled oscillator, a switch stage, and a pMOS cross-coupled pair which is used to release the design constraint between the conversion gain and the start-up condition. Since the switch stage and the pMOS cross-coupled pair are stacked on the nMOS differential oscillator, the bias currents of the switch stage and the pMOS cross-coupled pair can be entirely reused, so as to reduce the power dissipation. The experimental results show a conversion gain of 6.5 dB at 2.1 GHz associated with a single-sideband (SSB) noise figure of below 13 dB. The oscillator mixer also exhibits a tuning range of 184 MHz and a phase noise of ？116 dBc/Hz at 1-MHz offset from the LO frequency of 6.8 GHz, and it consumes 11 mA from 1.8 V bias voltage.