A Novel Qcm Mass Sensing System Incorporated with A 3-Dof Mode Localized Coupled Resonator Stiffness Sensor

This paper reports on a QCM (quartz crystal microbalance) mass sensor under atmospheric pressure that is combined with a 3-DOF micromachined coupled resonator operating in vacuum. With nanoparticles consecutively added on the QCM, the output signals from the QCM is then modified to produce electrostatic forces which are fed to a 3-DOF mode localized weakly coupled resonator. The 3-DOF coupled resonator hence utilizes the input electrostatic force as stiffness perturbations to perform the sensing operation. A comparison of three sensitivity characterization methods was carried out: resonance frequency shift, amplitude change and resonance vibration amplitude ratio. The results demonstrate that a 3-DOF mode localized coupled resonator incorporated with a QCM mass sensor has potential to be employed as a direct liquid contact biochemical transducer.