Sources of Sound in Piezoelectric Crystals

Abstract

The production of sound in piezoelectric crystals is examined from the viewpoint of the inhomogeneous wave equation. It is shown that sound is generated by a gradient in the piezoelectric stress and that consequently the free surfaces of a piezoelectric crystal are usually the most effective wave sources. The excitation of sound at microwave frequencies is also discussed and shown to be equivalent to the case of rf excitation at low frequencies.