Spot Poled Membrane Hydrophone Design

It has been demonstrated that PVDF based membrane hydrophones have negligible degradation in sensitivity with time, as well as good temperature stability and manufacturing reproducibility [10]. Also, a comprehensive model of the membrane hydrophone sensitivity transfer function has been developed [11]. This model incorporates multiple PVDF layers and amplifier characteristics, as well as the electrical cable and load. 

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The discovery of strong piezoelectricity in PVDF has led to the development of numerous polymer based acoustic sensors, in particular the spot poled membrane hydrophone design in its various embodiments. These hydrophones have become the primary devices for characterizing biomedical ultrasound fields. Their development has made possible the quantification of medical ultrasound exposure levels, and so enabled standards organizations to adopt a rational and systematic approach to address the problems of field measurements and device safety. Significant measurement challenges remain, particularly in the area of therapeutic ultrasound, but it is clear that PVDF will continue to play a pivotal role in the characterization of medical ultrasound devices. 

Harris, G.R. (1982) Sensitivity considerations for PVDF hydrophones using the spot poled membrane design, IEEE Trans. Sonics Ultrason., 29, 370-7. 

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