Analysis of a thickness-shear mode vibrator for the accelerometer in vector hydrophones

Typical hydrophones in line array sensors used to detect covert underwater targets can measure only sound pressure magnitude with the limitation of being unable to identify the direction of an incoming wave. In this paper, a thickness-shear mode vibrator is proposed as the main component of an inertia-type vector hydrophone to measure both the magnitude and direction of acoustic signals from targets. The piezoelectric single crystal lead magnesium niobate-lead titanate with rhombohedral 3 m symmetry constitutes the vibrator. The directional voltage response of the vibrator to an external force is derived, and the validity of the derived response is verified through fabrication of a piezoelectric single crystal vibrator and by comparison of its measured characteristics with the analysis results.