This article focuses on the design of super compact, polarization insensitive with wide angular stability, ultrathin triple-band metamaterial absorber. The unit cell comprising patches achieves almost perfect absorption (close to 100%) at C, X, and Ku band thereby justifying the term perfect metamaterial absorber. The structure provides 99.96%, 99.98%, and 99.62% absorptivity at the 4.75 GHz (C-band), 9.47 GHz (X-band), and 14.40 GHz (Ku-band), respectively. The dimension of the structure is super compact of the order of 7.2 × 7.2 × 0.8 mm³ along with the ultrathin profile. The unit cell thickness is 0.012 λ_lowest (where λ_lowest is at a lowest cut-off frequency). The proposed absorber comprises an outermost ring, split ring, innermost ring and square line with triangle patches at the boundary. The combinational effect of rings and internal patch provides perfect absorption at designated frequencies. Further, equivalent circuit is explained for the proposed design. The absorptivity remains insensitive towards transverse electric and transverse magnetic polarized wave and exhibits matched absorption. Moreover, the stability of the proposed design is validated with the different incident (for TE and TM modes) and polarization angles. The results are found close to perfect absorption. Finally, the simulated results are validated with measured results and found in close agreement.

中文翻译：

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用于 C、X 和 Ku 波段应用的超紧凑超薄完美广角偏振独立超材料吸收器的设计

本文重点介绍超紧凑、偏振不敏感、宽角稳定性、超薄三频超材料吸收器的设计。包含贴片的晶胞在 C、X 和 Ku 波段实现了几乎完美的吸收（接近 100%），从而证明了完美超材料吸收体这一术语的合理性。该结构在 4.75 GHz（C 波段）、9.47 GHz（X 波段）和 14.40 GHz（Ku 波段）下分别提供 99.96%、99.98% 和 99.62% 的吸收率。该结构的尺寸为 7.2 × 7.2 × 0.8 mm ³数量级的超紧凑型以及超薄型材。晶胞厚度为 0.012  λ_最低（其中λ_最低处于最低截止频率）。提议的吸收器包括最外环、开口环、最内环和边界处带有三角形贴片的方形线。环和内部贴片的组合效果可在指定频率下提供完美的吸收。此外，还解释了建议设计的等效电路。吸收率对横向电和横向磁极化波保持不敏感，并表现出匹配的吸收。此外，所提出的设计的稳定性通过不同的入射角（对于 TE 和 TM 模式）和偏振角进行了验证。结果发现接近完美吸收。最后，模拟结果与测量结果进行验证，并发现非常一致。