Enhanced sensitivity of quartz crystal proximity sensors using an asymmetrical electrodes configuration

A new approach for using quartz resonator (QR) with asymmetrical electrodes for proximity detection has been proposed. This approach takes advantage of the sensitive ability of QR to external electric stimulus. The proximal detecting target disturbs the fringing electric field generated near the electrodes of QR, and changes the series and parallel resonance frequencies of QR. Our experimental results indicate that the parallel resonance frequency is more suitable to be used as a measure parameter, and the detection sensitivity can be significantly enhanced by using an asymmetrical electrodes configuration. The proximity detection sensitivity of the '5-3' QR is about 8 times larger than that of the traditional '5-5' QR. More interesting, we found that the detection sensitivity enhancement of QR using the asymmetrical electrodes configuration does not weaken the stability of the QR. Meanwhile, the influence of physicochemical properties of the detecting targets on the proximity sensing properties of QR has also been studied. This approach provides simple and cost-effective method to achieve proximity detection. (C) 2017 Elsevier B.V. All rights reserved.