Parametrically tunable coupling factor for the weakly coupled resonators

In this paper, we presented the electrostatic tuning functions of the coupling factor for the weakly coupled resonators (WCRs) for the first time. A WCRs system with two mechanical coupled double-ended-tuning-fork (DETF) resonators is designed, fabricated and tested to verify the tuning theory. In consistency with the theoretical expectations, the experimental results show that the coupling factor is in a quadratic function with the bias voltage, and the coupling factor exponentially decays with the relevant geometry parameters. A large tunable range of the coupling factor with the minimum value of ~0.000917 and the maximum value of ~0.00196 is obtained by tuning the bias voltage applied on the WCRs. It lays the foundation for controlling the sensitivity and resolution of the WCRs based sensors.