A frequency-tunable microactuator with a varied comb-width profile

A frequency-tunable microactuator with a varied comb-width profile for electrostatic, post-fabrication frequency tuning has been demonstrated. The theoretical comb-width profile was derived to obtain a constant electrostatic stiffness, independent of the position of the combs. A tunable microactuator, having 186 pairs of the varied comb-width profile, was designed and fabricated by the standard surface micromachining process. Under a biased voltage of 150 V, the resonant frequency was tuned and reduced by 55% from the initial resonant frequency of 19 kHz and the corresponding effective stiffness was decreased 80% from the initial value of 2.64 N/m. As such, this scheme can be applied to comb-shape, electrostatic-based microsensors and microactuators for active frequency tuning applications.