This article develops a broadband absorber by fully using the radiation features of monopole antennas for ultrawide-angle absorption application. A unit cell (UC) based on monopole antennas is proposed, and its working polarization is analyzed with the antenna reciprocity method and image theory. A wide-angle impedance matching layer is also introduced to further enhance the absorption at large angles. The optimized monopole-based UC reveals 90% absorptivity from 5.5–14.76 GHz at the incident angle of 80°. To the best of our knowledge, this is the first time to report an absorber that can work perfectly under such ultrawide angles in a broadband manner. An 11 × 36 array is configured and simulated to verify the effectiveness of the monopole-based UC. The monostatic and bistatic scattering are both reduced significantly as well as other diffuse scattering directions from the simulated results. A prototype of 110 mm × 360 mm is fabricated and measured. Time gating methods are adopted to diminish the direct coupling effect. The measurements are in good agreement with the full-wave simulation results.

中文翻译：

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一种基于单极子的超大角度宽带吸波材料

本文充分利用单极天线的辐射特性，研制了一种宽带吸收体，用于超广角吸收应用。提出了一种基于单极天线的晶胞（UC），并利用天线互易法和镜像理论分析了其工作极化。还引入了广角阻抗匹配层以进一步增强大角度的吸收。优化的基于单极子的 UC 在 80° 入射角时显示 90% 的吸收率，范围为 5.5–14.76 GHz。据我们所知，这是第一次报道可以在宽带方式下在如此超广角下完美工作的吸收器。配置和模拟 11 × 36 阵列以验证基于单极的 UC 的有效性。从模拟结果来看，单基地和双基地散射以及其他漫散射方向都显着减少。制作并测量了 110 mm × 360 mm 的原型。采用时间门控方法来减小直接耦合效应。测量结果与全波仿真结果非常吻合。