High Frequency Vibration Analysis Of Quartz Crystal Array Devices Excited By Lateral Electric Fields

Quartz crystal microbalance(QCM)is a key area of biochemical sensor research.With the development trend of high precision,miniaturization and simultaneous measurement of sensors,multichannel quartz crystal microbalances(MQCM)has emerged.For a long time,the drive mode of QCM is thickness field excitation(TFE),which is a pure mass effect sensor.Such sensors have low detection sensitivity for small molecular weight biochemicals and are not sensitive to changes of electrical properties of analytes.Lateral field excitation(LFE)sensors have high sensitivities on changes of electrical characteristics.Moreover,LFE is more easily arrayed and miniaturized than TFE.The LFE mode has a good application prospect in the field of biosensors.In this paper,high frequency vibrations of the LFE array devices are analyzed based on Mindlin's first-order theory of piezoelectric plates and three-dimensional finite element method.The main research content is as follows.Dispersion relations of electroded regions and unelectroded regions are obtained by the free vibration analysis,and then the spectral relation is acquired to determine the size of the crystal plate.Though the forced vibration analysis of the LFE array sensor with double resonance elements,the motional capacitance is obtained,thereby the resonant frequency satisfying energy-trapping properties is determined from models coupling analysis.Besides,the influence of the parameters such as the width of the electrode,the gap value and the mass ratio on energy-trapping properties and vibration displacement of the devices are analyzed,as well as the effect of various parameters of the LFE-B resonator on the vibration characteristics of the LFE-A.Finally,the influence of various parameters of the device on the frequency shift and frequency interference of LFE-A were studied by finite element method and theoretical method.In this study,the theoretical research method of the LFE array devices is given,which can provide theoretical guidance for the optimal design of the LFE array devices.