Properties of sensors based on shear-horizontal surface acoustic waves in LiTaO3/SiO2 and quartz/SiO2 structures.

Acoustic wave devices based on waveguide modes with shear-horizontal polarization, i.e., Love modes, are very promising for sensor application, especially in liquid environments. They can be used for the determination of liquid density and viscosity as well as for chemical sensors. Up to now, several systems have been reported based on standard ST quartz. Those devices lack temperature stability, which is essential for field application. Thus, temperature-compensated systems based on different Y-rotated quartz and lithium tantalate (LiTaO3) plates with SiO2 guiding layers have been investigated. Temperature behavior as well as relevant acoustic properties were considered. Furthermore, experimentally determined data for device sensitivity are compared with theoretical predictions from numerical calculations.