Feasibility study of a resonant accelerometer with bistable electrostatically actuated cantilever as a sensing element

We report on a feasibility study of a resonant accelerometer incorporating fringing electrostatic fields actuated cantilever serving as a sensing element. Device's dynamics are described using the reduced order (RO) Galerkin and numerical finite differences (FD) models, the finite elements (FE) analysis is used for the evaluation of the electrostatic forces. The architecture of the electrodes designed to be thicker than the cantilever allows tuning of the beam behavior in a wide range, starting from linear and up to bistable responses. By choosing an appropriate value of the actuating voltage close to the bistability threshold the cantilever can be positioned in the configuration where the frequency sensitivity of the device to the electrode's deflection is enhanced while the frequency itself is higher than in the initial inactuated state. In accordance with the model results, by integrating the bistable cantilever with a proof mass, it is possible to design a highly sensitive resonant accelerometer with the state of the art performance.