Eliminating stray and suppressing unwanted radiation in a high frequency circuit is difficult. It becomes a challenge to achieve an ultra-wide absorption band in a thin-single-layer microwave absorber. In this article, a novel polarization-independent, ultra-wideband, light-weight, thin microwave absorber has been investigated numerically and experimentally. The proposed absorber unit cell consists of two concentric circular rings loaded with lumped resistances placed on top surface of a dielectric substrate. Unit cell size is 0.28 λL * 0.28 λL * 0.067 λL, which is compact in configuration (where λL is the wavelength corresponding to lowest frequency of operation). The proposed design provides more than 90% absorption in the frequency range of 6.7 GHz to 20.58 GHz (fractional bandwidth of 101.7%). The novelty of the proposed work lies in designing a wideband and ultra-thin absorber by using optimum unit cell geometry, resistance loading, and air column loading. Combination of these techniques results in a very wide band absorber design. Four fold structural symmetricity makes the absorber polarization insensitive. The absorber is compact, light-weight (used air as spacer), and thin (only 0.067 λL thick) and provides an alternative to construct wideband absorber for electromagnetic interference reduction.

中文翻译：

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基于电阻同心圆环的超宽带偏振不敏感薄吸收体


消除高频电路中的杂散并抑制不需要的辐射是很困难的。在薄单层微波吸收体中实现超宽吸收带成为一个挑战。在本文中，对一种新型的偏振无关、超宽带、轻质、薄型微波吸收器进行了数值和实验研究。所提出的吸收体单元由两个同心圆环组成，这些圆环负载有放置在介电基板顶面上的集总电阻。晶胞尺寸为0.28 λL * 0.28 λL * 0.067 λL，结构紧凑（其中λL是最低工作频率对应的波长）。所提出的设计在 6.7 GHz 至 20.58 GHz 频率范围内提供超过 90% 的吸收率（分数带宽为 101.7%）。该工作的新颖性在于通过使用最佳晶胞几何形状、电阻负载和气柱负载来设计宽带超薄吸收器。这些技术的结合产生了非常宽带的吸收器设计。四重结构对称性使得吸收器偏振不敏感。该吸波器结构紧凑、重量轻（使用空气作为垫片）且薄（厚度仅为 0.067 λL），为构建宽带吸波器以减少电磁干扰提供了一种替代方案。