Design of a MEMS Accelerometer in COMSOL Multiphysics and a Pickup Circuit Model in Matlab Simulink

In this study, multiple models of the sensing element for a capacitive accelerometer were developed, and a preliminary analysis was conducted to assess the alignment of the first natural frequencies along the x and y axes. Models exhibiting discrepancies in their first frequencies relative to these axes were excluded due to non-compliance with the requirement for low cross-sensitivity. Consequently, two models with a sufficient separation of natural frequencies along the x and y axes, compared to other axes, were selected. The transfer functions for displacement/acceleration and capacitance/displacement were identified as key characteristics for integrating the models into Matlab SIMULINK software. Given that the natural frequencies of the sensing element significantly exceed the maximum frequency of the measured signal, the frequency-dependent transmission characteristics were neglected. A single differential capacitance model was employed to simulate the capacitance-displacement relationship. Under an acceleration of 15g, the output signal from the accelerometer was measured at 276 mV.