School of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, 151-744, Korea.
Nat Commun. 2018 Dec 10;9(1):5255. doi: 10.1038/s41467-018-07697-7.
In spite of the extensive studies of zero-index metamaterials, the realization of zero impedance with finite phase velocity has not been explored. Here, we show that this extreme case, realized by elaborately-tuned paired resonators, can effectively enhance sensing and actuation. To explain the formation mechanism of the near-zero effective impedance with finite phase velocity by paired resonators at a target frequency, a theory using an equivalent model based on mechanical longitudinal waves is developed. If the frequency of the extreme property is further tuned at a Fabry-Pérot resonance frequency, highly efficient enhancement is possible. Experiments using a piezoceramic transducer (PZT) installed on the plate region bounded by two resonators confirm that the proposed extreme property mechanism highly enhances the sensing and actuation outputs of the transducer.
尽管对零折射率超材料进行了广泛的研究，但具有有限相速度的零阻抗的实现尚未得到探索。在这里，我们展示了通过精心调谐的配对谐振器可以实现这种极端情况，这可以有效地增强传感和驱动能力。为了解释在目标频率下由配对谐振器实现的具有有限相速度的近零有效阻抗的形成机制，提出了一种基于机械纵波的等效模型理论。如果进一步在法布里-珀罗共振频率下调整极值的频率，则可以实现高效增强。使用安装在两个谐振器限定的板区域上的压电陶瓷换能器 (PZT) 的实验证实，所提出的极值机制可以极大地增强换能器的传感和驱动输出。
