Efficient scattering-free wavefront transformation with power flow conformal bianisotropic acoustic metasurfaces
Efficient scattering-free wavefront transformation with power flow conformal bianisotropic acoustic metasurfaces
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DOI：
10.1063/5.0033422
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发表时间：
2021-02
影响因子：
4
通讯作者：
Xiuyuan Peng;Junfei Li;Chen Shen;S. Cummer
中科院分区：
文献类型：
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作者：
Xiuyuan Peng;Junfei Li;Chen Shen;S. Cummer
双各向异性超表面实现了高效的波前变换。然而，无源无损双各向异性超表面必须在超表面上的每个点上保留局部功率，这阻碍了其在处理除平面波以外的复杂波场中的应用。本文将功率流保形设计方法与双各向异性单元胞相结合，以满足这一限制。我们提出的方法提供了一种具有最大功率效率的任意波前变换的通用方法。作为验证，设计了一种传输型声学超表面，该超表面在近场聚焦3000 Hz平面波机载声音，理论上功率效率为单位。通过数值模拟和实验验证了该超表面的有效性。
Bianisotropic metasurfaces have enabled highly efficient wavefront transformation. However, a passive and lossless bianisotropic metasurface must conserve local power at every point over the metasurface, hindering its application in handling complicated wavefields other than plane waves. In this paper, the power flow-conformal design methodology and bianisotropic unit cells are combined to comply with such a restriction. Our proposed approach provides a general recipe for arbitrary wavefront transformation with maximum power efficiency. As a demonstration, a transmission-type acoustic metasurface was designed to focus 3000 Hz plane wave airborne sound in the near field with theoretically unitary power efficiency. The metasurface was validated by both numerical simulation and experiment.