Design and Characterization of a Tuning Fork Microresonator Based on Nonlinear 2:1 Internal Resonance

This paper focuses on the design of a tuning fork microresonator that utilizes its inherent inertial nonlinearities for its operation. Two orthogonal in-plane modes of the microresonator are carefully designed so that the natural frequency ratio between the higher and the lower frequency modes is close to two. When we electrostatically excite the higher frequency mode with the excitation voltage higher than some threshold, the lower frequency mode gets autoparametrically excited due to a nonlinear resonance phenomenon known as two-to-one (2:1) internal resonance. We employed the MEMS Integrated Design for Inertial Sensors (MIDIS), a high vacuum bulk-micromachining process, by Teledyne Dalsa to fabricate the proposed microresonator. We then experimentally demonstrate the 2:1 internal resonance phenomenon occurring in the resonator and highlight its applicability in developing the resonating MEMS based sensors.