Applicability of Acoustic Plate Modes with Quasi-Longitudinal Polarization to Liquid Parameterization

摘要

A class of acoustic waves suitable for liquid parameterization is demonstrated not to be restricted to acoustic modes with shear-horizontal polarization. Its substantial extension can be achieved by adding widespread plate modes with quasi-longitudinal (QL) polarization. Their investigation is performed by an example of 128°-rotated Y-cut LiNbO_3 plates. The sensitivity of plate modes to the conductivity of liquid adjacent to one of the plate surfaces has been found to depend on a mode number, a plate thickness, and elec-tric conditions on the opposite surface. It is demonstrated that their sensitivity to temperature is affected by the liquid viscosity. One of the QL modes existing in the 128°Y, X + 90° -LiNbO_3 plate has been determined numerically. Its applicability for monitoring the electric characteristics of low-viscous liquid media has been examined experimentally.