A NEW MULTILAYER PLANAR PVDF STANDARD HYDROPHONE AND ITS APPLICATIONS

A new type of PVDF hydrophone, the multilayer planar PVDF hydrophone, is described in this paper. The hydrophone disturbs measured acoustic fields very little and has a high sensitivity. The noise-equivalent pr essure of the hydrophone is 45 dB re 1 mu Pa per Hz bandwidth. The wor king frequency range of the hydrophone is 20 kHz similar to 4 MHz. In the range 100 kHz similar to 1 MHz, the hydrophone has a flat frequenc y response with sensitivity -205 dB +/- 1.5 dB (0 dB = 1 V/mu Pa). In this range, the hydrophone has been used for five years as a standard one. Two other applications (measurements of noise spectra and ultraso nic imaging) are also reported.