An 8-element common-mode-coupled 106 GHz fundamental oscillator with −111 dBc/Hz phase noise at 1 MHz offset

Phase noise reduces in a coupled array of oscillators at an ideal rate of 3N dB for 2
^N
oscillators. Concept of “common-mode coupling” is introduced as a robust technique in reducing phase noise in mm-wave frequencies. A 106 GHz 8-element common-mode coupled Colpitts oscillator is implemented in a 130 nm SiGe HBT BiCMOS technology with a measured phase noise of -111 dBc/Hz at 1 MHz offset while consuming 90 mW. The core differential Colpitts oscillator uses a resonant biasing scheme to reduce phase noise. The improvement of phase noise compared to the stand-alone oscillator is 9 dB showing the effectiveness of the proposed coupling scheme.