Sensitivity Analysis for Dual-Membrane Capacitive MEMS Microphone

Sensitivity is one of the most important properties of a microphone. The commonly used methods to analyze microphone sensitivity include lumped parameter method (LPM) and finite element method (FEM). The intricate structure of the capacitive dual-membrane microelectromechanical systems (MEMSs) microphone poses challenges for the two methods. The lumped-parameter method is computationally efficient but lacks precision in describing the complex structure, while the FEM can effectively analyze structural influences albeit with lower computational efficiency. To address this, in this article, the combination of LPM and FEM is used to analyze the sensitivity of MEMS microphones with dual-membrane structure, which can not only ensure the calculation accuracy of FEM but also greatly improve the calculation efficiency. In this way, several main parameters affecting the sensitivity of MEMS microphones with double membrane structure are analyzed, such as the gap distance between the membrane and the backplate, the diameter of the pillar connecting the two membranes, the volume of the front cavity, and the membrane tension.