Electromagnetic interference (EMI) shielding is essential at minimizing cost in the X and Ku frequency bands utilized for radar and defense applications. Development and characterization of lightweight, cost-effective carbon nanofiber (CNF) based epoxy nanocomposites for wideband EMI shielding application is the primary focus of this work. CNF epoxy nanocomposites are prepared with a minimum thickness of 0.5 mm at various CNF concentrations from 0.1 to 8 wt.%. SEM analysis ensures uniform dispersion of fillers and spectroscopic measurements like Raman and X-ray photoelectron spectroscopy ensures the chemical composition, molecular structure, and electron states of the developed nanocomposite material. DC conductivity follows the classical law of percolation theory with a percolation threshold of 1.5 wt.%. The AC conductivity of prepared CNF-based nanocomposites follows the universal dynamic response when the filler content is beyond the percolation threshold. The variation of permittivity with varying filler concentration exhibits the various polarization mechanisms and dielectric loss in the nanocomposite material. The measured shielding effectiveness for 4 wt.% and 8 wt.% CNF content in the X and Ku bands confirms with 99% and 99.9% diminution of electromagnetic radiation, respectively, absorption is the dominant mechanism, thus lowering the chances for further electromagnetic interference. The high shielding effectiveness of the prepared nanocomposites is due to the inherent stacked cup structure of CNF, and the high aspect ratio of CNF used. The shielding efficiency of the prepared material increases with the frequency change from X-band to Ku-band.

中文翻译：

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开发具有成本效益的碳纳米纤维环氧纳米复合材料，用于轻型宽带 EMI 屏蔽应用

电磁干扰 (EMI) 屏蔽对于最大限度降低用于雷达和国防应用的 X 和 Ku 频段的成本至关重要。开发和表征用于宽带 EMI 屏蔽应用的轻质、具有成本效益的碳纳米纤维 (CNF) 基环氧纳米复合材料是这项工作的主要重点。CNF 环氧纳米复合材料以 0.5 毫米的最小厚度在 0.1 至 8 重量％的各种 CNF 浓度下制备。SEM 分析确保填料的均匀分散，拉曼和 X 射线光电子能谱等光谱测量确保开发的纳米复合材料的化学成分、分子结构和电子状态。直流电导率遵循渗流理论的经典定律，渗流阈值为 1.5 wt.%。当填料含量超过渗透阈值时，制备的基于 CNF 的纳米复合材料的 AC 电导率遵循通用动态响应。介电常数随填料浓度的变化表现出纳米复合材料中的各种极化机制和介电损耗。X 和 Ku 波段中 4 wt.% 和 8 wt.% CNF 含量的测量屏蔽效率分别证实，电磁辐射减少了 99% 和 99.9%，吸收是主要机制，从而降低了进一步电磁干扰的机会. 所制备的纳米复合材料的高屏蔽效率是由于 CNF 固有的叠杯结构，以及所使用的 CNF 的高纵横比。