Tunable resonators with electrostatic self test functionality for frequency selective vibration measurements

In this paper we present an array of tunable resonators for frequency selective vibration measurements. The resonance frequency tuning is carried out by electrostatic forces directly applied to the seismic mass affecting the total stiffness. Frequency selective sensor systems require the exact knowledge of the resonance frequency. Therefore a method of in-system calibration using electrostatic excitation and capacitive vibration detection was investigated. Coupling problems of the excitation signal into the detection path were solved by using two excitation signals 180° out-of-phase and by contacting the substrate with a backside metallization.