High-stiffness-driven micromechanical resonator oscillator with enhanced phase noise performance

A two-port micromechanical beam resonator driven by its high stiffness locations has been used to enable a series-resonant resonator oscillator, for the first time, with enhanced power handling and phase noise performance as compared with the same resonator design but using low-stiffness driving configuration. The key to attaining better power handling capability relies on driving electrode arrangement where critical handling power becomes much larger by driving the resonator at its high-stiffness locations than low-stiffness areas since power handling of a resonator is proportional to its effective stiffness. With 16.9X improvement on power handling capability for a 9.7-MHz beam resonator via the proposed high-stiffness driving concept, a MEMS-based oscillator referenced to it greatly benefit from power handling enhancement, therefore leading to 26.5 dB reduction in far-from-carrier phase noise as compared to its low-stiffness driving counterpart.