Precise estimation of viscosity of liquid using leaky surface acoustic waves propagating along liquid/polymer/LiNbO/sub 3/ structures

A surface acoustic wave (SAW) propagating on a LiNbO/sub 3/ substrate has a large shear horizontal (SH) displacement. However, it is not possible to make a good estimate of the viscosity using the substrate for the case of the small viscosity liquids, such as water, because the propagation loss is relatively large. The polymer film/LiNbO/sub 3/ structure is proposed for the leaky SAW substrate. By using this substrate, an almost perfect SH mode can be attained. The loss is caused principally by the viscous coupling. Consequently, the viscosity coefficient can be well estimated even in the case of water.<
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