A new sensing system has been designed by using SH-SAW delay line. 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° 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. A sensing system is then presented for the effective operation of the reflective SAW sensor In particular the electronic circuit system for precise measurement of the phase characteristics of the reflected surface wave is shown.
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