Cross-Board Synchronization of Oscillators Embedded with Phase-Difference Adjusting

This study proposes a new method for the synchronization of radio-frequency oscillators with the functionalities of frequency locking and phase-difference tuning. Unlike the published methods of oscillator synchronization by injection-locking networks and coupling networks proposed for beamformer control, it uses a floating ground node connection between oscillators as the physical realization of synchronous metronome over a rolling plate with cans placed underneath. Not only frequency locking is well-achieved, but also the phase-difference between the neighbor oscillators is coherent and can be adjusted. The experimental results illustrate that adjustable range is around 160°. It is beneficial for the massive antenna design and releases the constraint of spatial separation between beamformer elements.