Reflection of bulk waves at a piezoelectric crystal-viscous conductive liquid interface

TLDR: In this paper, the reflection of obliquely incident shear horizontal (SH) bulk acoustic waves at the interface between a piezoelectric crystal and a viscous conductive liquid is theoretically investigated.

Abstract: The reflection of obliquely incident shear horizontal (SH) bulk acoustic waves at the interface between a piezoelectric crystal and a viscous conductive liquid is theoretically investigated. In addition to viscous entrainment and mass loading effects, it is shown that the presence of a reflection‐generated external electric field offers the possibility of acoustoelectric interaction with charged particles and dipoles in the solution. These interaction mechanisms could be exploited for liquid chemical analysis and biosensor applications. Expressions are obtained for the reflection coefficients (amplitude and energy) and phase shift upon reflection in terms of the angle of incidence, wave frequency, crystal parameters, and liquid properties (density, viscosity, dielectric constant, and conductivity) by using the normal wave impedance and the input impedance of the interface. It is shown that the sensitivity of such acoustic wave detectors could be tailored by properly choosing the interdigital transducer (I...