MEMS طراحي يك شتاب سنج خازني

Design Synthesis of a Capacitive Type MEMS Accelerometer

In this paper, a capacitive type MEMS accelerometer is designed based on surface micromachining technology. The synthesis is limited to the mechanical part not the electronic conditioning circuits. A lateral comb type transducer is selected: The design layout is based on manufacturing limitations of MUMPs; a surface micromachining technology for polysilicon. The sensor parameters were obtained for an automotive application in the airbag systems. To reach the desired bandwidth and good stability, a (force) feedback system was used applying negative stiffness. The comb spring stiffness was derived analytically. A finite element analysis was also conducted to verify the results. Other performance characteristics of the sensor such as shock resistance and transverse sensitivity (which were complicated to drive analytically) were calculated by finite element simulation within an optimization algorithm to meet the required sensor specifications.