Understanding the role of resonances and anti-resonances in shaping surface-wave bandgaps for metasurfaces
Understanding the role of resonances and anti-resonances in shaping surface-wave bandgaps for metasurfaces
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DOI：
10.1063/5.0093083
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发表时间：
2022-10
影响因子：
3.2
通讯作者：
L. Pillarisetti;C. Lissenden;P. Shokouhi
中科院分区：
文献类型：
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作者：
L. Pillarisetti;C. Lissenden;P. Shokouhi
瑞利波传播路径中的表面安装棱柱谐振器阵列产生两种不同类型的表面波带隙：纵向和弯曲谐振带隙，分别由瑞利波与谐振器的纵向和弯曲谐振混合产生。纵向谐振带隙较宽，具有不对称的传输下降，而弯曲谐振带隙较窄，具有近对称的传输下降。在本文中，我们通过研究谐振器的谐振和反谐振来阐明这些观察结果。在了解瑞利波如何与不同边界条件相互作用的基础上，我们研究了由于谐振器的谐振和反谐振而由棱柱谐振器施加的钳位条件，并解释了所得的透射谱。我们证明，在单个谐振器的情况下，只有谐振器的纵向和弯曲谐振负责抑制瑞利波。相反，对于谐振器阵列，谐振器的谐振和反谐振都有助于纵向谐振带隙的形成，这与仅弯曲谐振起作用的弯曲谐振带隙不同。我们还通过评估谐振器施加的钳位条件，对纵向谐振带隙内观察到的传输下降的不对称性提供了解释。最后，我们通过改变晶胞的几个关键几何参数来评估谐振器阵列在反谐振频率下的传输特性。这些发现提供了基于将反谐振频率与入射瑞利波频率匹配来设计优化谐振器所需的概念理解，以实现增强的瑞利波抑制。
An array of surface-mounted prismatic resonators in the path of Rayleigh wave propagation generates two distinct types of surface-wave bandgaps: longitudinal and flexural-resonance bandgaps, resulting from the hybridization of the Rayleigh wave with the longitudinal and flexural resonances of the resonators, respectively. Longitudinal-resonance bandgaps are broad with asymmetric transmission drops, whereas flexural-resonance bandgaps are narrow with nearly symmetric transmission drops. In this paper, we illuminate these observations by investigating the resonances and anti-resonances of the resonator. With an understanding of how the Rayleigh wave interacts with different boundary conditions, we investigate the clamping conditions imposed by prismatic resonators due to the resonator’s resonances and anti-resonances and interpret the resulting transmission spectra. We demonstrate that, in the case of a single resonator, only the resonator’s longitudinal and flexural resonances are responsible for suppressing Rayleigh waves. In contrast, for a resonator array, both the resonances and the anti-resonances of the resonators contribute to the formation of the longitudinal-resonance bandgaps, unlike the flexural-resonance bandgaps where only the flexural resonances play a role. We also provide an explanation for the observed asymmetry in the transmission drop within the longitudinal-resonance bandgaps by assessing the clamping conditions imposed by the resonators. Finally, we evaluate the transmission characteristics of resonator arrays at the anti-resonance frequencies by varying a few key geometric parameters of the unit cell. These findings provide the conceptual understanding required to design optimized resonators based on matching anti-resonance frequencies with the incident Rayleigh wave frequency in order to achieve enhanced Rayleigh wave suppression.