In this study, the authors present two new proposals for representation by the equivalent circuit model for aperture-type circular ring geometries, not yet studied in the literature. The study consists of the frequency response representation of frequency selective surfaces (FSSs) formed by circular ring aperture and concentric circular ring apertures. At first, the authors performed an equivalent circuit analysis for a single cell formed by a single circular ring. Then, they extend the analysis to concentric circular rings, which when used as FSS unit elements, present two passband responses. They compare results of the proposed method with results obtained with the commercial software ANSYS HFSS, showing a good agreement between the results. They built four prototypes and compared measured results with simulated results obtained with the suggested method and it completes the proposed equivalent circuit validation.

中文翻译：

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等效电路模型，用于分析具有环形和双同心环形孔径的频率选择表面

在这项研究中，作者提出了两个新的建议，以用等效电路模型来表示孔径型圆环几何形状的方法，这在文献中尚未进行研究。该研究包括由圆环孔和同心圆环孔形成的频率选择表面（FSS）的频率响应表示。首先，作者对由单个圆环形成的单个电池进行了等效电路分析。然后，他们将分析扩展到同心圆环，当用作FSS单元元素时，它们呈现两个通带响应。他们将建议方法的结果与使用商业软件ANSYS HFSS获得的结果进行了比较，表明结果之间有很好的一致性。