基于双各向异性超构表面的高效声场调控研究

Acoustics has a wide range of applications in the fields of medicine, communication, industry and military. One of the most critical issues is to control the sound fields according to specific needs. The sound field control based on metasurfaces is currently a research hotspot. However, since the conventional metasurfaces with symmetric response cannot satisfy the impedance matching with both incident and transmitted field, the control efficiency of sound field is greatly limited. In response to this problem, this application intends to introduce a bianisotropic metasurface with the asymmetric response, exploring the theory of the sound field control and designing the artificial microstructure units applicable to bianisotropic metasurfaces, which may achieve an efficient control of sound field with impedance matching simultaneously with the incident and transmitted fields. In addition, the asymmetry of the bianisotropic metasurfaces increases the degree of freedom of the sound field control. Therefore, this application is also intended to study the diverse and excellent applications of sound field control that can achieve independent control of reflection and transmission sound fields. The research results of this application will contribute to the in-depth development of the research on the bianisotropic metasurfaces. It has the crucial important theoretical and practical significance in improving the efficiency and extending the application range of the existing sound field control and studying the mechanism of generating complex specific sound field distributions.

声学在医学、通信、工业及军事等领域中具有非常广泛的应用，这其中最关键的问题之一是对声场按照特定的需求进行调控，基于超构表面的调控是目前的研究热点。然而，由于具有对称响应的传统超构表面无法同时与入射和透射声场满足阻抗匹配，这在很大程度上限制了声场调控的效率。针对此问题，本申请项目拟引入带有非对称响应的双各向异性超构表面，研究适用于此种超构表面的声场调控理论，设计此种超构表面的人工微结构单元，实现与入射和透射场同时满足阻抗匹配的高效声场调控。此外，由于双各向异性超构表面的非对称性增加了声场调控的自由度，故拟同时展开对可实现反射与透射声场独立控制的多样和优异声场调控应用的研究。本申请项目的研究成果将有助于双各向异性超构表面相关研究的深入开展，在改善已有声场调控的效率、扩展声场调控的应用范围以及产生复杂特定声场分布的机制研究等方面均有着至关重要的理论和实际意义。

声学在医学、通信、工业及军事等领域中具有非常广泛的应用，这其中最关键的问题之一是对声场按照特定的需求进行调控，基于超构表面的调控是目前的研究热点。然而，由于具有对称响应的传统超构表面无法同时与入射和透射声场满足阻抗匹配，这在很大程度上限制了声场调控的效率。.针对上述问题，本项目引入带有非对称响应的双各向异性超构表面，研究适用于此种超构表面的声场调控理论，设计此种超构表面的人工微结构单元，实现与入射和透射场同时满足阻抗匹配的高效声场调控。本项目推导了适用于带有非对称响应的声学双各向异性超构表面的理论公式，建立了相应的调控模型，得到适用于双各向异性超构表面的高效声场调控理论体系。设计构建了三层非对称镀膜迷宫结构组成单元，讨论了此单元各参数对其性能的影响，研究其内部物理机制，得到了其非对称材料参数与几何之间的理论关系。基于该结构单元构建了带有非对称响应的双各向异性超构表面，促进了相关声学器件的实用化。根据带有非对称响应的双各向异性超构表面的特点和性能，实现了异常声折射、声聚焦、声束自弯曲等三个高效的声场调控应用。相比于对称响应的传统超构表面，在仿真和实验中分别得到了最大63%和12%的透射能量效率提升。.本项目的研究成果将可能有助于双各向异性超构表面相关研究的深入开展，增加超构表面对声场的调控自由度和潜在的应用范围，实现高效率的声场操控，并为超构表面器件的进一步实用化提供理论和实验基础。