A V-band Differential Colpitts Push-Push VCO in 130 nm SiGe BiCMOS

A V-band push-push VCO operating from 68.5 GHz to 73 GHz is presented. This design introduces a capacitor at the common-base node, which enhances odd mode oscillation and maximizes the common-mode impedance of the differential oscillator. At the output end, a transformer is used to decouple both fundamental and 2nd harmonic frequency signals. The desired 2nd harmonic frequency signal is delivered to the output, whereas the fundamental frequency signal can be fed back for phase-detection in a phase-locked loop. The implemented VCO delivers a peak output power of 1.2 dBm at 72.5 GHz, and achieves a phase noise of -103 dBc/Hz at 1-MHz offset, respectively. The circuit is designed on a 130 nm SiGe BiCMOS technology with $f_{T}/f_{max}$ of 200/300 GHz. The total power consumption of the signal source is 50 mW with a supply voltage of 1.8 V.