Novel Quartz Crystal Capacitive Sensor for Micro Displacement Detection

In this paper, a novel quartz crystal capacitive sensor, which consists of a uniplanar scattering-field capacitance and a piezoelectric quartz crystal resonator, was proposed for micro displacement detection. The developed sensor can directly convert the displacement between detective object and capacitance disk to resonant frequency output. The test results indicated that the quartz crystal capacitive sensor exhibit high sensitivity response (3.05 Hz/μm in the range of 20-200 μm). In additional, the fundamental frequency dependence of resonant frequency response versus displacement was also investigated. The result shows that quartz crystal capacitive sensor with higher fundamental frequency can obtain higher sensitivity. Finally, we examine the sensor response to different dielectric materials. This paper suggests that quartz crystal capacitive sensor shows a potential application for micro displacement detection.