In this paper, a polarization-insensitive high transmittance bandpass filter with low radar cross section (RCS) in both S- and X-band is proposed. This is the first study to use the partition layout loading approach for conformal structures with transmissive windows, reducing the operating band RCS. Curved structures have stronger radiation at a smaller angle to the incident wave, and that is how their scattering differs from uniform scattering from flat structures. The structure is divided by analyzing the radiative contribution of different regions. The surface was discussed in regions according to surface angles, and a new partition layout loading method was used to suppress the side currents and decreased backward scattering, achieving a backward RCS reduction of more than 10 dB at 4-8 GHz (66.7%). The bandpass layer operating at 6.9 GHz is designed through equivalent circuit theory. In combination with the lossy layer, absorption above 0.8 at 3.7-5.6 GHz and 9.1-12.5 GHz was achieved. Further, the structure was fashioned into a curved surface with varying curvature, demonstrating its effective absorption and transmission properties across different curvatures. A 15 × 15 cell structure was designed and fabricated, and there was good agreement between the test results and simulation results. The proposed structure has important applications in radomes, conformal structures, and electromagnetic shielding.

中文翻译：

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S、C、X 波段共形频率选择性吸收器，具有低后向散射

本文提出了一种在 S 和 X 波段均具有低雷达截面（RCS）的偏振不敏感高透射率带通滤波器。这是第一项针对具有透射窗口的保形结构使用分区布局加载方法的研究，从而降低了工作频带 RCS。弯曲结构在与入射波的角度较小的情况下具有更强的辐射，这就是它们的散射与平坦结构的均匀散射的不同之处。通过分析不同区域的辐射贡献来划分结构。根据表面角度进行区域讨论，并采用新的分区布局加载方法来抑制侧向电流并减少后向散射，在4-8 GHz（66.7％）下实现了10 dB以上的后向RCS降低。工作在6.9 GHz的带通层是通过等效电路理论设计的。与有损层结合，在 3.7-5.6 GHz 和 9.1-12.5 GHz 的吸收率达到了 0.8 以上。此外，该结构被制成具有不同曲率的曲面，展示了其在不同曲率下的有效吸收和传输特性。设计并制作了15×15的电池结构，测试结果与仿真结果吻合良好。所提出的结构在天线罩、保形结构和电磁屏蔽方面具有重要应用。