Static and dynamic characterization of micro-electro-mechanical system repulsive force actuators

Abstract

This paper presents the static and dynamic response characterization of an electrostatic micro-electro-mechanical system mirror driven by repulsive force. The experimental analysis of the static response in different seasons of the year indicates that the capillary force caused by the thin layer of water underneath the mirror is the dominant factor for variation in the lifting threshold of the applied voltage. Dynamic characterization of the mirror reveals a large natural frequency of 2.6 kHz at the increasing rate of 8 Hz/V, indicating a four-fold increase compared to a previous design. This high natural frequency with an almost linear increase is desired for fast speed scanners and interferometers with high tunability benefited from the simplified signal processing circuit. Since the amplitude of the repulsive force micro-structure is no longer restricted to any geometrical limitation, the non-dimensionalizing parameters are chosen so that the nonlinear terms are small enough in order that the perturbation method is applicable in the vicinity of both primary and principal parametric resonances. The analytical analysis shows the way for inserting a bookkeeping parameter in a simple manner based on the evaluation of the magnitude of order in which the pre-assumed value is further validated by experimental results. The results of our investigations can be used to analytically evaluate the static and dynamic behavior of the system and have important applications in the design of various devices such as filters, interferometers, and switches.