可重构超材料吸收体(MA),由可调元件或可变形结构组成,能够响应环境变化而改变其吸收带宽和振幅。在构建可重构MA的选项中,折纸/kirigami结构显示出巨大的潜力,因为它们能够结合出色的机械和电磁(EM)性能。然而,基于试错的设计方法和复杂的制造过程都不能满足开发高性能MA的要求。因此,这项工作介绍了一种基于深度学习的算法来实现折纸MA的快速逆设计。然后,手风琴折纸编码MA生成可重构EM响应,可以在超宽带吸收(5.5-20GHz,折叠角α=82°)和高反射(2-20GHz,RL>-1.5dB,在y偏振波下α=0°)。然而,非对称编码模式和手风琴折纸变形导致典型的偏振敏感吸收性能(2-20GHz,RL>-4dB,在x偏振波下α<90°)。第一次,具有可切换操作频带的kirigami偏振旋转表面适用于平衡正交偏振波下手风琴折纸MA的吸收性能。因此,堆叠的折纸-kirigamiMA在β=0°时保持偏振不敏感的超宽带吸收(4.4-20GHz),并且可以通过变形转化为窄带吸收体。此外,适应的折纸/kirigami结构具有优异的机械性能,如低相对密度,负泊松比,和可调比能量吸收。此外,通过调节MXene纳米片之间的PEDOT:PSS导电桥,开发了一系列具有可调平方电阻(5-32.5Ω/sq)的低浓度MXene-PEDOT:PSS油墨(〜46mg·mL-1),以通过丝网印刷制造超材料。由于通用的设计方案,这项工作为开发低成本和高性能的可重构EM吸收器提供了一个有希望的范例。
Reconfigurable metamaterial absorbers (MAs), consisting of tunable elements or deformable structures, are able to transform their absorbing bandwidth and amplitude in response to environmental changes. Among the options for building reconfigurable MAs, origami/kirigami structures show great potential because of their ability to combine excellent mechanical and electromagnetic (EM) properties. However, neither the trial-and-error-based design method nor the complex fabrication process can meet the requirement of developing high-performance MAs. Accordingly, this work introduces a deep-learning-based algorithm to realize the fast inverse design of origami MAs. Then, an accordion-origami coding MA is generated with reconfigurable EM responses that can be smoothly transformed between ultrabroadband absorption (5.5-20 GHz, folding angle α = 82°) and high reflection (2-20 GHz, RL > -1.5 dB, α = 0°) under y-polarized waves. However, the asymmetric coding pattern and accordion-origami deformation lead to typical polarization-sensitive absorbing performance (2-20 GHz, RL > -4 dB, α < 90°) under x-polarized waves. For the first time, a kirigami polarization rotation surface with switchable operation band is adapted to balance the absorbing performance of accordion-origami MA under orthogonal polarized waves. As a result, the stacked origami-kirigami MA maintains polarization-insensitive ultrabroadband absorption (4.4-20 GHz) at β = 0° and could be transformed into a narrowband absorber through deformation. Besides, the adapted origami/kirigami structures possess excellent mechanical properties such as low relative density, negative Poisson\'s ratio, and tunable specific energy absorption. Moreover, by modulating the PEDOT:PSS conductive bridges among MXene nanosheets, a series of low-concentration MXene-PEDOT:PSS inks (∼46 mg·mL-1) with adjustable square resistance (5-32.5 Ω/sq) are developed to fabricate the metamaterials via screen printing. Owing to the universal design scheme, this work supplies a promising paradigm for developing low-cost and high-performance reconfigurable EM absorbers.