Characteristic of leaky surface acoustic wave propagating along liquid/SiO/sub 2LiNbO/sub 3/ and its application to liquid sensor

We propose polystyrene/(36/spl deg/ rot. Y-X) LiNbO/sub 3/ and SiO/sub 2/ (fused silica)/(36/spl deg/ rot. Y-X)LiNbO/sub 3/ structures for the viscosity sensor, in which the shear horizontal (SH) component of the leaky surface acoustic wave (LSAW) becomes larger than that of the case without polystyrene and/or SiO/sub 2/. For glycerin/SiO/sub 2/ (40 /spl mu/m)/(36/spl deg/ rot. Y-X) LiNbO/sub 3/, the propagation loss of LSAW due to the viscosity of glycerin is four times larger than that for glycerin/(36/spl deg/ rot. Y-X)LiNbO/sub 3/ (30 MHz). Therefore, the viscosity coefficient of liquids is well estimated from the propagation loss of LSAW. >