Page 10 - HydrophoneHandbook_eReader_Ed2_20151208
P. 10

Hydrophone Handbook


The general construction of a needle hydrophone consist of a
piezoelectric sensing material (e.g., ceramic or PVDF) and
electrodes in contact with opposite sides. The sensor is mounted
to a supporting structure and is affixed to an absorbent backing
material to increase the mass to limit any ringing at the resonant
frequency of the its piezoelectric material. A physical schematic
of a needle hydrophone is shown below:

Sound Field          P- (rarefactional)
                     P+ (compressional)

                               Piezoelectric Sensor
                               Passivation Layer
                               Metallization Layer
                               Supporting Structure
                               Backing Material



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