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 2 ^nd harmonic frequency signals. The desired 2 ^nd 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.