The realm of flexible devices has seen considerable advancement in recent technology due to their ability to bend and conform to particular shapes. Flexible metamaterial absorbers offer the advantage of combining the features of conventional metamaterials with the attributes of conformal systems, thereby opening new avenues in electromagnetic technology. This work involves the realization of flexible metamaterial absorbers with epoxy/graphene nanoplatelets-silver nanowire (GnP-AgNW) polymer composites as substrates; with a bandwidth enhancement achieved by incorporating losses in the substrate and combining resonances in the unit cell. A novel in-situ technique is employed to synthesize the nanohybrid GnP-AgNW (GA) with different weight percentages of AgNWs grown on GnP (GAx; x = 10, 15, 20 wt%). The dielectric measurements of the polymers showed that an increase in weight percentages of AgNWs in the composite enhanced the dielectric constant as well as losses of the polymer (ε՛: 7.7 to 8.8 and ε՛՛: 0.62 to 1.12). The numerical study on the designed flexible metamaterial absorbers with these substrates of thickness 1.4 mm showed a maximum absorptivity of 99% with a bandwidth (having absorption >90%) varying between 1.2 and 1.86 GHz. The experimental measurements on the fabricated metamaterial absorber were found to match the simulation results closely. The polymer composites demonstrated in this work are attractive candidates as substrates for metamaterial absorbers for conformal applications. This paper approaches the problem of bandwidth enhancement of metamaterial absorbers by material engineering along with the resonant structure optimization leading to a synergetic effect in the properties of absorber.

中文翻译：

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以环氧树脂/石墨烯纳米片-银纳米线聚合物复合材料为基底的柔性带宽增强超材料吸收体

柔性设备领域由于其弯曲和符合特定形状的能力而在最新技术中取得了长足的进步。柔性超材料吸波器具有将传统超材料的特征与共形系统的属性相结合的优势，从而开辟了电磁技术的新途径。这项工作涉及以环氧树脂/石墨烯纳米片-银纳米线（GnP-AgNW）聚合物复合材料为基底实现柔性超材料吸收器；通过合并基板中的损耗并结合晶胞中的共振来实现带宽增强。采用一种新颖的原位技术合成纳米杂化 GnP-AgNW (GA)，其中不同重量百分比的 AgNW 在 GnP 上生长（GAx；x = 10、15、20 wt%）。聚合物的介电测量表明，复合材料中AgNW重量百分比的增加提高了聚合物的介电常数和损耗（εε：7.7至8.8和εε：0.62至1.12）。对使用厚度为 1.4 mm 的基板设计的柔性超材料吸收器进行的数值研究表明，最大吸收率为 99%，带宽（吸收 >90%）在 1.2 至 1.86 GHz 之间变化。发现对制造的超材料吸收器的实验测量与模拟结果非常匹配。这项工作中展示的聚合物复合材料是作为保形应用超材料吸收器基底的有吸引力的候选者。本文通过材料工程以及谐振结构优化来解决超材料吸收器的带宽增强问题，从而产生吸收器性能的协同效应。