Frequency stability of micromechanical beam oscillator under subharmonic synchronization

Frequency stability plays a key role in MEMS oscillator's performance. Synchronization phenomenon has been found useful to improve the short term frequency stability. However, to our knowledge, the influence of subharmonic synchronization on frequency stability hasn't been reported yet. In this work, a micromechanical clamped-clamped beam oscillator is implemented with a piezoresistive sensing closed loop circuit and works in its nonlinear regime. A subharmonic synchronization is observed when it is subject to an external perturbation, and the short term frequency stability along with its contributory factors of perturbation intensity and frequency detuning is studied for the first time. The experimental results show that the oscillation frequency stability is found steady in the subharmonic synchronization region and the short term frequency stability can be further slightly improved by using a larger perturbation intensity.