Piezoelectric composite hydrophone array

The C-3 composite thin film, consisting of lead titanate (PT) powder embedded in a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer matrix were prepared by a spin-coating method. The ceramic and copolymer phases of the composite film were poled in opposite directions. The piezoelectric and pyroelectric coefficients of the composite film were measured. Since the piezoelectric coefficients of PT and P(VDF-TrFE) have opposite signs while the pyroelectric coefficients have the same sign, the composite film has a higher piezoelectric but lower pyroelectric coefficient than P(VDF-TrFE). This composite film was then used to fabricate an eight-element hydrophone array and the performance of the hydrophone array was evaluated in water. The hydrophone array has good receiving sensitivity in the frequency range of 2-8 MHz. The angular responses of the array element were characterized and the experimental results agreed well with the theoretical predictions. The acoustical and electrical cross-coupling between the array elements were discussed.