An All-Quartz Integrated Resonant Accelerometer With High Sensitivity and Stability: Design, Fabrication, and Measurement

This study proposed an all-quartz integrated resonant accelerometer, composed of a quartz pendulum as mass-spring system and quartz double-ended tuning forks (DETFs) as resonators. The detection principle is based on force-frequency characteristic, which the vibration frequency of DETF would change once the z-axis acceleration provokes axial stress variation of vibrating beam. In order to achieve high sensitivity, critical dimensions were analyzed, selected, and simulated. Homogeneous material, integration arrangement, and isolation structure were utilized to eliminate internal mismatch, ensure high-quality resonator, and suppress external disturbance to stabilize the output of sensor. Then, the components of the sensitive structure, the pendulum and DETF, were fabricated through compatible MEMS technology separately, and the prototype was finished by microassembly and package. Experimental platform was built up and the fundamental performances were obtained, such as full-scale range (FSR) of 70 g, bandwidth of more than 150 Hz, scale factor (SF), rotary output, and nonlinearity, which implies high sensitivity as 75.346 Hz/g. Besides, short-time stability of zero bias and SF and full-temperature stability were measured. The 0 g stability for 3 h, bias instability of 1.85 ~\mu \text{g} , and resolution were measured, calculated, and analyzed as well. All performances verified the high stability of proposed accelerometer, which is comparable or better compared with state-of-the-art counterparts. The experiment results complied with theoretical analysis and suggested its feasibility in the realm of high-precise field.