Modeling and Simulation on the Condenser Microphone with Stepped Backplate

In recent years, the mobile devices are popular such as notebooks and smart phones. MEMS microphones with small size and high performance are ideal for consumer electronics products. MEMS microphone’s structure including the diaphragm, the acoustic holes of backplate, the air gap and the back chamber. This study describes vibration behavior of the microphone diaphragm by the equivalent mechanical model and combines the electrical sensitivity of the capacitance to complete the condenser microphone model. This study improve the microphone performance including the sensitivity, signal-to-noise ratio and total harmonic distortion by optimizing the electrode area of the backplate. We present a stepped structure of the backplate, and study the effects of the microphone performance by changing the geometry of the stepped structure. We optimize the geometry of the stepped structure to get the best performance of the microphone, and compare the microphone performance between the stepped backplate and the traditional flat backplate.