Sensing properties of normal oscillatory modes of quartz plates

The responses (relative velocity variations Deltav/v of normal (symmetric or asymmetric) Lamb and shear-horizontal modes of ST-cut quartz plates, whose thickness is comparable with the wavelength, is studied. Since modes of different orders n belonging to these two families have different propagation velocities v(n), polarizations u(i), and displacement distributions in depth H, they exhibit different responses to variations in the parameters of the plate (density, elastic moduli, thickness, and temperature) and to the loading of its surface by thin films (i.e., to surface adsorption). Results of numerical calculation of the responses to these parameters are corroborated by experiments on the effect of the plate temperature variation and the effect of adsorption of water vapor onto the plate surface. (C) 2004 MAIK "Nauka/Interperiodica".