During the last decades thickness shear mode resonators (TSM, QCM) have been object of comprehensive research. Many approaches were made to describe the behavior and physical effects when loaded. We present a physical model that describes the TSM in the full frequency range, including overtones for a large variety of loadings (e.g. gases, liquids or solid materials). By using an automated curve fit algorithm, absolute values for the loaded material (e.g. thickness, viscosity) can be extracted. The model has been validated with a large number of experiments including liquids with complex viscosities, biomolecule interactions, electrochemisty or vacuum deposition techniques. Additionally, the appearance of layer resonances have been predicted and verified. Layer resonances are remarkable because they appear at even-numbered overtones, which have been considered to be impossible.
Brünig, R., Weihnacht, M., Guhr, G., & Schmidt, H. (2010). Complex loading and simulation of acoustic thickness shear mode resonator. In Procedia Engineering (Vol. 5, pp. 476–479). Elsevier Ltd. https://doi.org/10.1016/j.proeng.2010.09.150