PVDF reference hydrophone development in the UK-from fabrication and lamination to use as secondary standards

During the last 30 yrs, PVDF has been used extensively as a sensor material. Over this period, the GEC-Marconi Research Centre has developed a wide range of devices based on PVDF as a piezoelectric transducer material. The ability to create laminated structures has led to an enhancement in performance and has allowed innovative designs to be realized. This paper describes the development of the laminated PVDF structure and its benefits, such as increased sensitivity and improved signal to noise ratio. Examples of devices utilizing the lamination process are given in the form of both a bilaminar-shielded membrane hydrophone and a PVDF sonar hydrophone. Performance properties of both types of hydrophones are presented along with a discussion of their use as secondary standard hydrophones at the National Physical Laboratory (NPL).