Measurement of acoustic properties of liquid using liquid flow SH-SAW sensor system

The SH-SAW resonator having narrow bandwidth and higher e value has been us ed for sensing the properties in ionic and viscosity of liquid. The surface acoustic waves with the shear horizontal displacement (SH-SAW) are excited on a piezoelectric substrate; 36 rotated Y cut X prop. LiTaO3 (36 YX LiTaO 3) and the liquid flow sensing system was constructed by using two-port res onator on the substrate. The flow of a sample liquid was interacted with th e SAW only on the cavity of the resonator. The resonator was connected in a n amplifier, to construct an SH-SAW oscillator. The frequency changes of th e SH-SAW oscillator were detected as a sensor response. Experimental result s showed that the response of the SAW sensor varied with both the conductiv ity and the square root of product of the density and viscosity of the liqu id. Transit responses of the SAW sensor system to the flow of the sample li quid also showed a specific feature. It was found that these quantities wer e very useful to determine the properties of liquid, (C) 2001 Elsevier Scie nce B.V. All rights reserved.