The study on the design and performance analysis of acoustic metamaterial lens

Acoustic lens focusing is a commonly used method in high-intensity focused ultrasound (HIFU). However, traditional acoustic lens focusing suffers from low focusing efficiency and excessive sidelobes, which affect the efficacy and safety of HIFU treatment. To address this issue, this paper designs a periodic trapezoidal‑groove acoustic metasurface lens by leveraging the extraordinary acoustic transmission effect. Subsequently, its focal sound‑pressure level is calculated through theoretical analysis and finite‑element simulation, and is further validated experimentally. Finally, the influence of structural parameters-such as the period, center width, depth, and taper angle of the trapezoidal groove, as well as the amplitude of the excitation source-on the focusing performance of the acoustic metasurface lens is systematically analyzed. The results demonstrate that the periodic trapezoidal‑groove acoustic metasurface lens can further enhance focusing and suppress sidelobes within a specific frequency range; the frequency corresponding to the maximum sound pressure is determined by the period of the trapezoidal groove; and the shift of Wood's anomaly frequency is primarily governed by the groove depth. This study provides insights for the development of high‑performance acoustic‑lens-focused ultrasound transducers.