Abstract

Surface Acoustic Wave Propagation in the Presence of Strong External Field

M.Kosek (Department of Electrical Engineering, Technical University in Liberec, Libeerc, Czech Republic)

e-mail: miloslav.kosek@vslib.cz

The paper deals with the change of small amplitude surface acoustic wave (SAW) velocity in the presence of strong generalised field, for example the electric one [1]. The velocity change can be determined by the perturbation theory. The results of its application to non-linear piezoelectric state equations are linear equations with slightly changed coefficients, termed effective ones. The difference between real and effective coefficients is approximately proportional to the field strength. Then the standard procedure of SAW propagation can be applied to linear equations. As a result of computational procedure the sensitivity of SAW velocity to the external field is found. The calculations are made for both the typical cuts of quartz and lithium niobate. The lithium niobate is more sensitive than quartz. A possible practical application of this effect is a miniature sensor of electric field. However, precautions must be made to eliminate the temperature effects that are much stronger that effects due to the measured electric field. Possible solutions are outlined. [1] Zelenka, J., Kosek, M.: Properties of surface acoustic wave devices under strong external fields. Physical Acoustics - Fundamentals and Applications, ed. by O. Leroy and M. A. Breazeale, Plenum Press, 1991, pp. 708-713.

Section : 2