Experimental Study of pre-Stressed Micromechanical anti-Spring Structures

Hongcai Zhang, Yuxing Duan, Yang Gao, Xueyong Wei

Abstract: This paper presents a comparison study of asymmetrical and symmetrical anti-spring structure for MEMS inertial sensors. Positive and negative pre-stressed voltages were introduced to study the system's response. The simulation in COMSOL shows the 3-spring has a higher sensitivity. In the positive pre-stressed range, both the 3-spring and 4-spring systems show good linearity with the preload V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-</sub> and are respectively, -9ppm/V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , -1.83ppm/V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> > 0.999. In the negative prestressed range, the 4-spring systems also show good linearity with preload V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-</sub> and are -2.85ppm/V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> while the 3-spring system's frequency shows quadratic with V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-</sub> . The special performance determines the choice of the type of anti-spring structure due to the application requirements.