Wide tuning range W-band Colpitts VCO in 90 nm CMOS

A compact wide tuning range design of a CMOS voltage-controlled oscillator (VCO) at W-band frequencies is presented. The design employs a differential Colpitts configuration, using a bufferless transformer output and nested inductors. The gate bias is used for frequency tuning that achieves a wide range of 93.7–100.7 GHz. A peak output power of 4.7 dBm with power efficiency of 5.5% is achieved at 98.8 GHz and the phase noise is around −80 dBc/Hz at 1 MHz offset across the tuning range. The VCO uses a silicon area of 0.15 mm2 including pads and, depending on bias, consumes between 6–63 mW of DC power.