Depolarizing-field effect in piezoelectric resonators

The depolarizing-field effects in piezoelectric crystals and resonators have been discussed in relation to the electromechanical coupling coefficients. The sound propagation in an infinite medium is studied based on the modified piezoelectric constitutive relations derived, in which the relevant components of electrical variables are preserved in an explicit form. Results are applied to the analyses of vibrations under parallel- and perpendicular-field excitations of plate resonators. The extensional vibration of a bar with longitudinal piezoelectric coupling is dealt with in an approximate procedure. In addition, some topics are discussed from the aspects of the depolarizing-field effect, including the dispersions in ferroelectric KDP and photoconductive CdS.