Coupled vibration and frequency response of a micropillar-enhanced QCM sensor

A theoretical model of a quartz crystal microbalance carrying a layer of substrate and an array of micropillars based on the classical and modified Timoshenko beam theory was established. By choosing specific substrate thickness and micropillar height, this composite sensor approaches the coupled resonance state, and thus significantly improving the mass sensitivity. The intentionally designed sensor is extremely sensitive to tiny mass. However, with increasing mass, the mass sensitivity decreases sharply and then tends to be constant. The frequency shifts calculated by two models have some differences, but their mass sensitivity is almost the same.