Frequency tuning of a laterally driven microresonator using an electrostatic comb array of linearly varied length

We present a new post-fabrication frequency-tuning method for laterally driven electrostatic microresonators using a DC-biased electrostatic comb array of linearly varied finger-length. The electrostatic tuning force, and the modified stiffness, due to the DC-biased tuning-comb array, have been derived in terms of the tuning voltage. A set of frequency tunable microresonators has been designed and fabricated by 4-mask surface-micromachining process. The resonant frequency of the microfabricated microresonator has been measured for varying tuning voltage at the reduced pressure of 1 torr. The maximum 3.3% reduction of the resonant frequency is measured for a tuning voltage increase of 20 V