Fast algorithm for correction of material constants of piezoelectric crystals on SAW velocity experimental data

The paper presents a fast algorithm for accurate evaluation of material constants of piezoelectric crystals from SAW velocity experimental data. We use a nonlinear least squares method to fit the material constants to the measured SAW velocities. For a sufficient decrease of the computation time a perturbation procedure is used that gives an exact matrix of derivatives of SAW velocity with respect to material constants. That allows us to fit optimally the constants of crystals to experimental SAW velocity data using only 3 or 4 iteration steps. The algorithm is used for correction of material constants for LiTaO₃ crystals from measured SAW velocity data. Our constants are compared with those obtained by other authors. Both results are in good agreement. The applicability of the algorithm for correction of the temperature coefficient of material constants of crystals is also discussed