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