A 80GHz voltage controlled oscillator utilizing a negative varactor in 90nm CMOS technology

A 80 GHz voltage controlled oscillator is presented. It is shown that impedance transformation enables the transformation of a varactor capacitance into negative varactor partially canceling the capacitance of the differential pair. This enables the transmission line resonator to be longer and have a higher impedance. Design criterion for achieving negative varactor is also presented, and design issues of millimeter wave voltage controlled oscillators are discussed. The voltage controlled oscillator is fabricated in 90 nm CMOS technology and achieves a phase noise of -109 dBc/Hz at 10 MHz offset with 13 mW power consumption from a 1.2 V power supply.