Innovative Designs for Quartz Crystal Microbalance

Quartz crystal microbalance (QCM) is a piezoelectric sensor with multiple application such as antigen-antibody interactions, detection of virus capsids, protein adsorption, and DNA and RNA hybridization. The material of QCM model with diameter of 4.5mm in this research is AT-cut quartz since the resonance mode of AT-cut crystal is thickness-shear mode (TSM). The principle of QCM is sensing the change of resonance frequency caused by the variation of mass. Based on the theory of electricity, decreasing the separation distance and expanding the effective area of electric field are feasible solutions for improving QCM. According to these concepts, novel groove designs for QCM with gold electrodes were proposed to develop electric field distribution. Complete analysis for piezoelectricity and electricity of QCM was simulated via analysis software CoventorWare 2010. The analysis results reveal that innovative designs in this research fulfill the advantages such as larger effective area, lower crystal impedance, and higher quality factor.