Abstract: Starting from the piezoelectric crystal kinetic equation and other fundamental equations,we analysed the distribution of both the electric potential and charge on the grating induced by the incident wave with electrical perturbation technique to the crystal surface.Then a general integral formula of the scattered field is obtained through integral transformation with the electric charge induced by the incident wave acting as the exciting source.
The scattered SAW field on YZ-LiNbO₃ is then numerically calculated and the relation between the reflective or forward scattering coefficients and the width of the strip is given.Furthermore,the change of the incident wave velocity as passing through the grating is obtained.The agreement between our theory and the experiments is good.