Spatial Response of Arbitrarily Electroded Piezoelectric Plates by Plane-Wave Decomposition

Abstract

The spatial response of resonant piezoelectric plates used in various acoustic imaging systems is of significant practical interest and is closely related to the resolving ability of these systems. In a certain class of applications, in order to achieve the desired transducing action, the faces of the plate are only partially electroded. There, it is advantageous to be able to predict and control the spatial distribution of the acoustic output from the knowledge of the spatial distribution of the electrodes. A new technique is presented for determining the spatial distribution of the acoustic output of an arbitrarily electroded piezoelectric plate. This technique regards the transducer as a linear spatial system, with the electrode pattern considered as the input and the resulting acoustic particle displacement pattern immediately in front of the transducer in the propagation medium as the output. Once the spatial transfer function or the spatial impulse response of the system is known, the output for any electrode configuration can be found using Fourier techniques. Experimental measurements of the output of several piezoelectric plates due to different electrode patterns compare closely with calculations based on the above theory.