Coupled analysis on the micro-airflow and its actuator for MEMS fluidic devices

This paper primarily involves in coupled vibrating between the micro airflow and its electrostatic actuator in a MEMS sealed chamber structure. Both the air damping effect and the Rayleigh-ritz energy method have been utilized to investigate the coupled effect between the micro airflow and its actuator. The air pressure distribution of the micro airflow has been determined by solving the linerized isothermal compressible Reynolds' equation and combined with the sealed pressure boundary condition. The coupled model of electrostatic-Silicon membrane-micro airflow has been established according to the Rayleigh-Ritz energy method. From the coupled model, the undetermined coefficient of the displacement function of such coupled vibrating can be derived. By comparing the undetermined coefficient lambda of the displacement function without micro airflow and the undetermined coefficient lambda' of the displacement function with micro airflow, the air damping factor has been extracted. The influencing of micro airflow on electrostatic actuator can be exhibited by such air damping factor. And dynamic performance of this kind of MEMS fluidic devices can be improved by regulating and controlling the air damping factor. All the investigation provide theoretical foundation and control strategy for micro fluid actuating.