Semi-analytical formulation for the phase-noise analysis of injection-locked push-push oscillators

This paper presents a semi-analytical formulation for the phase-noise analysis of injection-locked push-push oscillators. The formulation provides insight into the noise spectrum and its corner frequencies, which can be related to some design parameters. It enables a direct comparison with the phase-noise spectrum of a single injection-locked oscillator, based on one of the two sub-oscillator circuits. The push-push configuration is optimized in order to increase the synchronization bandwidth and the phase-noise spectrum before and after this optimization is compared. The formulation, applied to 10.4 GHz oscillator, has been validated with the accurate conversion matrix approach and with experimental measurements.