Design and experimental analysis for innovative wide bandwidth vibration sensor

An innovative design for capacitive wide bandwidth vibration sensor is proposed and verified by experiments in this work. Three-dimensional and high-g vibration motions can be individually detected by the proposed vibration sensor such that the other-axis effect can be reduced and the sensitivity can be enhanced. The shock absorb mechanisms, i.e., fixed-fixed beam stopper and cantilever beam stopper, are employed against the external shock acceleration so that the damage and stiction can be prevented. In addition, the readout circuit calibrated the gain and offset of the output signal which can improve the signal to noise ratio. By a series of experiments, the width and height of fabricated element are 2.45mm and 2.55mm, respectively. The bandwidths are about 15kHz/15kHz/ 10kHz with respect to X-/Y-/Z-axis, respectively. The element sensitivities of the sensor are about 0.113fF/g, 0.113fF/g and 0.095fF/g, respectively. Furthermore, the 10kG shock acceleration can be successfully absorbed by the proposed shock absorb mechanisms.