A theoretical and experimental investigation into multilayered piezoelectric composite transducers

The behaviour of a number of 3-1 connectivity piezoelectric composite plate transducers is presented. The fundamental thickness mode resonance of such devices is found to be contaminated by lateral resonant activity; this is evidenced in the measured and predicted electrical impedance profile and the surface displacement data at the fundamental thickness mode. Measurements taken on the 3-1 devices infer that they are not acting as true composites. In addition to this the finite element technique is applied to a number of stacked 3-1 and 1-3 connectivity devices to predict the mechanical Q-factor, and hence bandwidth, as a function of polymer filler properties.