A Cymbal pressure-gradient vector hydrophone using PMNT single crystal

Abstract

Acoustic vector hydrophone is an underwater sound receiver, which can measure particle velocity, particle acceleration and pressure gradient. By using double flexural vibration disks as the driving element, a pressure gradient hydrophone of Cymbal structure is proposed. The dipolar mode of the Cymbal hydrophone can be excited by the vibration of the flexural disk and the dipolar directivity pattern of the hydrophone can been realised. The relaxor ferroelectric single crystal PMNT of perovskite structure has excellent piezoelectricity performance, which is used to improve the performance of the pressure gradient hydrophone. The pressure-gradient hydrophones of PMNT material and PZT-5 material are developed and measured. Results show that, the PMNT Cymbal pressure-gradient vector hydrophone has a dipolar directivity pattern and high sensitivity. The sensitivity of the PMNT hydrophone is 5dB higher than that of the PZT-5 hydrophone.