A study of electrostatic force nonlinearities in resonant microstructures

Abstract

This letter investigates the nature of amplitude frequency (A-f) dependence caused by nonlinearities in the parallel plate electrostatic transduced in resonant microstructures. We present analytical and experimental evidences that the A-f nonlinearities are practically always dominated by third order nonlinear terms. For an electrostatically unbalanced system, we show that the bias voltage at which second and third order nonlinearities have equal impact on A-f dependence corresponds to ∼90% of the dc pull-in voltage.