Vibration sensitivity reduction of two microwave oscillators using inter-injection locking technique

Phase noise is one of the most important specifications of microwave oscillators. External factors such as mechanical vibrations increase the phase noise of the oscillator. A novel technique is introduced to reduce vibration-induced phase noise using inter-injection locking of two coupled oscillators. Two similar oscillators with equal free running frequencies are chosen and are subjected to sinusoidal vibration. The mechanical configuration is such that vibration sensitivity vector increases the frequency of one oscillator and decreases the other one´s frequency of oscillation. Coupling these two oscillators using inter-injection locking, the common after-lock frequencies of both oscillators would be equal to the free running frequency of oscillation; as such the influence of vibration on the oscillators is reduced. Experimental measurements are carried out to confirm the proposed technique.