In this letter, a novel design of a narrow bandpass frequency selective surface (FSS) based on the utilization of the coupled method, which resonates at Ka -band frequencies between 29 and 30.3 GHz, is proposed and experimentally evaluated. A high selectivity was achieved, by coupling two metallic layers, which were based on the structure of a cross aperture and a rectangle grid patch, respectively. The simple symmetric patterns used in the proposed work have also made the FSS independent of polarization properties. Moreover, a high angular stability was also achieved since for electromagnetic (EM) wave incident at degrees from 0° to 75°, the frequency deviations were only 0.1% and 0.4% for TE and TM polarizations, respectively. For performance evaluation, an experimental FSS prototype was fabricated by a double-sided printed circuit board (PCB), which was composed of $50\times50$ unit cells in a dimension of 18 cm $\times18$ cm. A Keysight N5227A PNA and two-horn antennas in a chamber were setup to measure the performance. The experimental measurement results have shown a good agreement with the numerical simulations.

中文翻译：

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具有高角度稳定性的窄带通频率选择表面 K a-乐队

在这封信中，基于耦合方法的利用，一种新颖的窄带通频率选择表面（FSS）设计在 K a 提出并通过实验评估了29至30.3 GHz之间的宽带频率。通过耦合分别基于交叉孔和矩形网格补丁结构的两个金属层，可以实现高选择性。拟议工作中使用的简单对称图案也使FSS不受偏振特性的影响。此外，由于对于入射角为0°到75°的电磁波，TE和TM偏振的频率偏差分别仅为0.1％和0.4％，因此也实现了较高的角度稳定性。为了评估性能，实验性FSS原型是由双面印刷电路板（PCB）制成的，该双面印刷电路板由 $ 50 /次50 $ 尺寸为18厘米的晶胞 $ \ times18 $ 厘米。在腔室中设置了Keysight N5227A PNA和两个喇叭天线以测量性能。实验测量结果与数值模拟结果吻合良好。