Analysis and Design of Three-Axis MEMS Capacitor with High Dynamic Range and Operating Frequency

This study has designed, analyzed a three-axis capacitor accelerator in which micro-electromechanical systems technology is employed. The accelerometers are generally divided into three categories of single axis, two axes, and three axes in terms of their ability to measure acceleration. In the suggested structure in this paper, acceleration measurements are carried out on all the three axes simultaneously with the use of a mass and spring system, which makes it possible to achieve a high sensitivity at a low occupancy level without losing other accelerator factors. Due to taking difference in this structure, the effect of any axis acceleration on the measured acceleration of the other two axes has been very low. If any external factor (e.g., electromagnetic waves) changes the value of a single capacitor, the original output of the capacitor measured for detecting acceleration does not change. That is, designing is done in such a way that the acceleration of each axis does not affect the other two axes and the external factors cannot also disrupt the system performance. Among the other important characteristics of the accelerometers are dynamic range, operating frequency, and sensitivity. As an advantage, this study covers a dynamic range up to 1000g and an operating frequency up to 20 kHz. The accelerometer sensitivity has been obtained to be 4fF/g in the z axis direction and 9fF/g in the x and y axes directions.