Performance of transducers with segmented piezoelectric stacks using materials with high electromechanical coupling coefficient

TL;DR

This paper investigates how segmenting piezoelectric stacks with high electromechanical coupling materials like PMN-PT affects the performance of wideband underwater acoustic transducers, especially tonpilz types, compared to traditional designs.

Contribution

It provides a comparative analysis of segmented versus unsegmented stacks using high coupling materials, highlighting their impact on transducer performance for wideband applications.

Findings

Segmented stacks significantly influence performance with high coupling materials.

High coupling materials enable wider bandwidth transducers.

Design considerations differ for segmented and unsegmented stacks in high-performance transducers.

Abstract

Underwater acoustic transducers often include a stack of thickness polarized piezoelectric material pieces of alternating polarity interspersed with electrodes, bonded together and electrically connected in parallel. The stack is normally much shorter than a quarter wavelength at the fundamental resonance frequency, so that the mechanical behavior of the transducer is not affected by the segmentation. When the transducer bandwidth is less than a half octave, as has conventionally been the case, stack segmentation has no significant effect on the mechanical behavior of the device. However, when a high coupling coefficient material such as PMN-PT is used to achieve a wider bandwidth, the difference between a segmented stack and a similar piezoelectric section with electrodes only at the two ends can be significant. This paper investigates the effects of stack segmentation on the performance of wideband underwater acoustic transducers, particularly tonpilz transducer elements. Included is discussion of transducer designs using single crystal piezoelectric material with high coupling coefficient compared with more traditional PZT ceramics.