Design and simulations of a new biaxial silicon resonant micro-accelerometer

This paper presents a new biaxial silicon resonant micro-accelerometer. The device basically consists of a single proof mass, four pairs of decoupled beams, four lever mechanisms and two pairs of resonators, which provides 2-D in-plane acceleration measurement with the decoupled two pairs of resonators. Structure optimization is implemented by taking advantage of the finite element analyses. From the simulation results we can see that the effective frequencies of two acceleration sensitive modes are 1010.18 and 1010.13 Hz respectively, and the undesired modes and effective modes are isolated apparently. Additionally, high linear relationship between the input acceleration and the resonant frequency shifts of resonators are demonstrated by the input–output characteristic simulation. Moreover, simulation results reveal the scale factor for the x-axis is 180.03 Hz/g, and the scale factor for y-axis is 180.75 Hz/g, while the cross-axis sensitivity for x-axis is 0.046 Hz/g, and the cross-axis sensitivity for y-axis is 0.027 Hz/g. The high sensitivity and low cross-axis sensitivity are thus adequately confirmed. By the way, the simulation of temperature dependent characteristics demonstrate that the differential scheme can effectively suppress the influence of temperature variation, and the thermal analysis shows that the device can bear the thermal stress induced by temperature change. All these simulations above can verify the feasibility of the structure design.