Liquid sensor system using reflecting surface acoustic wave delay lines

A new sensor has been designed by using SH-SAW device. Shear horizontal mode surface acoustic wave (SH-SAW) has a unique characteristic of complete reflection at the free edges of the substrate. The SH-SAW are excited on a 36/spl deg/ YX LiTaO/sub 3/ and the right angle edge of the substrate has been used to reflect these waves. Both the phase and amplitude of the SH-SAW reflected from the edge were measured as a response of the sensor probe. Several experiments were performed to verify the edge reflection type SAW sensor in viscous and ionic liquids. Experimental results showed that the sensor is very suitable for sensing of liquid phase.