A 12-GHz low phase noise VCO by employing CMOS field-plate transistors

This paper presents a voltage-controlled oscillator (VCO) with low phase noise by employing the CMOS field-plate (FP) transistors. The proposed FP transistors perform the improvement in flicker noise (1/f noise) was demonstrated in our previous investigation. A complete large-signal model for FP transistors was established by modified BSIM4 model with lossy substrate networks. The proposed 12-GHz VCO with FP transistors was designed and fabricated in TSMC 0.13-mu m CMOS process. The measured characteristic of phase noise is 122 dBc/Hz at 1-MHz offset frequency. Compare with a conventional VCO, this novel design shows that the proposed VCO achieves lower phase noise about 5 dBc at offset frequency from 100-kHz to 1-MHz.