A millimeter-wave CMOS LC-Tank VCO with an admittance-transforming technique

A novel circuit topology suitable for millimeter-wave voltage-controlled oscillators (VCOs) is presented. With the admittance-transforming technique, the proposed VCO can operate at a frequency close to the f(max) of the transistors while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output power. Using a standard micrometer CMOS process, a U-band VCO is implemented for demonstration. The fabricated circuit exhibits a frequency tuning range of 1.1 GHz in the vicinity of 50 GHz. The measured output power and phase noise at I-MHz offset are - 11 dBm and - 101 dBc/Hz , respectively. Operated at a supply voltage of 1.8 V, the VCO core consumes a dc power of 45 mW.