Modeling and noise analysis of a fence structure micromachined capacitive accelerometer system

We analyze the effects of possible noise sources on a fence structure micromachined capacitive accelerometer system by modeling and simulation to improve its performance. Simulation results show that a mismatch between the two initial sensing capacitors of the accelerometer or a mismatch between the two capacitance-voltage conversion circuits has a great effect on the output noise floor. When there is a serious mismatch, the noise induced by a sinusoidal carrier is the major noise source. When there is no or only a slight mismatch, the differential capacitance-voltage conversion circuits become the main noise source. The simulation results were validated by experiments and some effective approaches are proposed to improve the system resolution.