Both absorption and diffuse reflection can effectively suppress microwave backward reflection. However, the challenge of designing wideband absorptive elements with anti-phase reflection hinders the simultaneous working of the two principles. With aid of the wideband characteristic of bilateral complementary structure, we propose a strategy to design wideband absorptive elements with large reflection phase differences. For proof of concept, the proposed elements are arranged in a rectangular grid by optimizing scattering field distribution. The proposed diffusion metabsorber achieves over 20-dB scattering field reduction in the range of 8.5–20.3 GHz with good polarization stability and high angular insensitivity of up to $\pm 40°$, which has been verified by real experiments. Furthermore, the proposed design strategy exhibits the potential to further reduce electromagnetic wave reflection, and the optical transparent characteristic is promising for window applications.

中文翻译：

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用于完美降低散射场的宽带扩散元吸收器

吸收和漫反射均能有效抑制微波后向反射。然而，设计具有反相位反射的宽带吸收元件的挑战阻碍了这两种原理的同时工作。借助双边互补结构的宽带特性，我们提出了一种设计具有大反射相位差的宽带吸收元件的策略。为了概念验证，通过优化散射场分布将所提出的元素排列在矩形网格中。所提出的扩散元吸收器在 8.5-20.3 GHz 范围内实现了超过 20-dB 的散射场降低，具有良好的极化稳定性和高达$\pm 40°$, 已通过实际实验验证。此外，所提出的设计策略显示出进一步减少电磁波反射的潜力，并且光学透明特性有望用于窗户应用。