A Wide Range Frequency Coherent Modulation Control Based on Modal Coupling Effect in MEMS Resonators

The modal coupling effect is a common phenomenon in MEMS resonators, whose typical representatives are the mechanical coupling and the capacitive coupling. The capacitive coupling is generated by the energy transfer between internal modes, especially by changing the electrical potential energy in MEMS resonators whose electrodes and resonant structure are shared. This paper presents a novel frequency modulation method by taking advantage of the modal coupling effect. It is demonstrated that the frequency coherent modulation control can be achieved by activating a coupled mode. The frequency modulation range is related to the response of the cavity mode and the sequential pump and reverse pump display different modulation potential. Moreover, the nonlinearity of the manipulated mode determines its shifting direction while the hopscotch is determined by the cavity mode’s nonlinearity. The frequency coherent modulation control induced by the modal coupling effect has proven to be an efficient method to tune the frequency in a wide range (more than 100 times its mechanical bandwidth).