A method to analyze mechanical noise in MEMS capacitive accelerometer

Mechanical noise is a critical factor in MEMS sensors. This study analyzes mechanical noise for the specific case of MEMS capacitive accelerometer. An analog behavioural model(ABM) has been proposed for the MEMS sensor taking into account capacitive sensing interface and electrostatic forces in the sensor. An expression for the power spectral density of mechanical thermal noise has been derived using equipartition theorem. The output power spectral density of the sensor has been evaluated by simulating ABM in pspice. Allan deviation and PSD plots are used to characterise the output random noise in the sensor. Experimental investigation using inclined plane setup validate the findings in simulation results.