ABSTRACT In recent years, the exotic capability of metamaterials to absorb perfectly electromagnetic wave has induced potentially many practical purposes, especially, the rapid growth of 5G/6G telecommunication systems. Therefore, the perfect metamaterial absorbers have been reduced in a fast way to several hundred times smaller than the working wavelength. However, it is still a big obstacle to obtain the real low-frequency perfect absorbers (LFPAs), since the absorption frequency and the physical size are two conflicting requirements. To overcome this limitation, we review rather briefly the existing optimization strategies for LFPAs, by which the merits of geometrical optimization and the hybridization with parasitic elements will be highlighted. In addition, to be more feasible in electronic devices, the studies on flexible LFPA are also mentioned. Especially, we focus on recent investigations, which use inkjet-printing as an advanced fabrication technique to create the cost-efficient, printable and flexible LFPA.

中文翻译：

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用于高级低频完美吸收体的超材料进展：简要回顾

摘要 近年来，超材料完美吸收电磁波的奇异能力已经引发了许多潜在的实际用途，尤其是 5G/6G 电信系统的快速增长。因此，完美的超材料吸收体已经迅速缩小到比工作波长小几百倍。然而，获得真正的低频完美吸收器（LFPA）仍然是一个很大的障碍，因为吸收频率和物理尺寸是两个相互矛盾的要求。为了克服这个限制，我们相当简要地回顾了现有的 LFPA 优化策略，通过这些策略将突出几何优化和与寄生元件混合的优点。此外，为了在电子设备中更加可行，还提到了对柔性 LFPA 的研究。特别是，我们专注于最近的研究，这些研究使用喷墨印刷作为一种先进的制造技术来创造具有成本效益、可印刷和灵活的 LFPA。