A New Coupling Spring Design for MEMS Tuning Fork Structures Demonstrating Robustness to Fabrication Errors and Linear Accelerations

Abstract

This paper presents a new coupling spring design for the MEMS tuning fork structure. The spring design incorporates the outer arm, inner arm, and torsional arm. The outer and inner arms are connected through the torsional arm to be rotationally symmetric, constituting 180° in relation to the center of spring. The designed coupling spring always prioritizes an anti-phase motion providing robustness to linear acceleration. The operation of the spring was validated through FEM simulations and experimental results. The experimental results demonstrated that the anti-phase resonant frequency was 27,280 Hz, whereas the in-phase resonant frequency was 27,780 Hz. Furthermore, the designed coupling spring benefited from a narrow etch cavity and small surface area, making it an ideal design for consumer electronics applications.