A high sensitivity and wide frequency band vector hydrophone using PZT-based four spiral beam structure

•A novel MEMS vector hydrophone of four spiral beams and a PA microsphere structure is proposed.•The new structure enhance the surface area of the piezoelectric film, thereby improving the sensitivity and working band.•The MEMS vector hydrophone features a simple and consistent fabrication process.•The MEMS vector hydrophone achieves a high receiving sensitivity of up to -181.51 dB at 1100 Hz (0 dB=1 V/μPa).•The hydrophone suitable for detecting micro-signals in underwater applications. The utilization of a high sensitivity and wide frequency band vector hydrophone exhibits significant potential in the exploration of underwater target. However, enhancing these performance remains a challenge due to limitations in materials and structures. Herein, we report a micro-electro-mechanical system (MEMS) vector hydrophone (FSPVH) built on lead zirconate titanate (PZT) film with four spiral beam structure and polyamide (PA) microsphere. The optimization of the structural dimensions and PZT thin film distribution has been the result of simulation. The FSPVH have been fabricated using MEMS technology, and the prototype has been assembled. The FSPVH was tested in a standing bucket wave calibration system. The results show that FSPVH achieve a sensitivity of −181.5 dB (0 dB = 1 V/μPa) at 1100 Hz, and the work bandwidth is 20–1330 Hz. Meanwhile, it exhibits a satisfactory “8″ shape directivity. This work provide theory and technique supports of vector hydrophone with high sensitivity and wide frequency band.