A Study on Electrostatic Tuning of Resonant Frequency for SOI-MEMS Resonators

Abstract

Electrostatic tuning characteristics of the electrostatic resonators fabricated using SOI-MEMS technology with various configurations and voltage bias conditions were systematically studied using the FEM simulator. The basic structures of the resonators consist of a 1mm×1mm proof mass and four 200μm-long, 3μm-wide beams, whose thicknesses are 10μm, resulting in the resonant frequencies of the fundamental resonant mode without applied voltages which were about 5kHz. The resonant frequencies of the resonators with parallel-plate electrodes decreased quadratically with the applied voltage, while those of the resonators with comb electrodes gave no significant change. When the influence of the substrate was taken into consideration, the resonant frequency change by the applied voltage was reduced by several percents.