Abstract Metamaterials usually require that the unit size a should be comparable to the wavelength λ . Although the λ / a relationship could tell us what size of unit we need and which method we should choose for the fabrication, it limits the application of metamaterials in the kHz and MHz frequency range, as the unit size would be on the order of 10 2 m, making the overall size of the metamaterial too large for practical application. In this paper, we firstly demonstrate that the λ / a relationship limitation could be overcome by a new kind of composite, which we have called carbon-based ‘meta-composite’. A SiO 2 matrix with periodic microstructure is fabricated by using self-assembly of SiO 2 microspheres, and amorphous carbon fills in the gaps to form a three-dimensional periodic carbon network. The experimental results indicate that the carbon network will introduce tunable electromagnetic properties, which could be precisely tailored by controlling the geometric size of the carbon network. It is worth pointing out that the unit size of the periodic carbon network is on the sub-micrometre level, but the wavelength is on the order of 10 2 m. This means that the meta-composite overcomes the λ / a relationship limitation in the kHz and MHz frequency range, which shows great potential for the miniaturization of electronic devices.

中文翻译：

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C/SiO 2 超复合材料：克服超材料中的 λ/a 关系限制

摘要 超材料通常要求单位尺寸 a 与波长 λ 相当。尽管 λ / a 关系可以告诉我们需要什么尺寸的单元以及应该选择哪种制造方法，但它限制了超材料在 kHz 和 MHz 频率范围内的应用，因为单元尺寸约为 10 2 m，使得超材料的整体尺寸对于实际应用来说太大。在本文中，我们首先证明了 λ / a 关系限制可以通过一种新的复合材料来克服，我们称之为碳基“元复合材料”。利用SiO 2 微球的自组装制备具有周期性微观结构的SiO 2 基体，无定形碳填充间隙形成三维周期性碳网络。实验结果表明，碳网络将引入可调电磁特性，可以通过控制碳网络的几何尺寸来精确定制。值得指出的是，周期碳网络的单位尺寸在亚微米级，但波长在10 2 m 量级。这意味着元复合材料克服了 kHz 和 MHz 频率范围内的 λ/a 关系限制，显示出电子设备小型化的巨大潜力。