In this article, a miniaturized 2.5‐dimensional frequency selective surface (FSS) bandstop filter operating at 2.4 GHz is presented. The proposed FSS contains meander lines as well as metallic patches on top and bottom layer of FR‐4 substrate, and vertical vias are employed to connect the top and the bottom layers. The proposed configuration significantly reduced the size of unit cell to 0.040λ₀ × 0.040λ₀ (where λ₀ is the free space wavelength) at the desired frequency of 2.4 GHz. Additionally, this element arrangement assists in achieving fractional bandwidth of 140%. The measured −10 dB bandwidth is from 1 to 4.5 GHz. The proposed FSS is polarization insensitive and highly angularly stable (up to 75°). The equivalent circuit model (ECM) of this FSS and related surface current distribution are also provided to understand its working mechanism. The design performance validation has been carried out through the construction and testing of a functional prototype. The full wave simulation, the ECM, and the measured results depict a promising agreement.

中文翻译：

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具有极化不灵敏性和斜稳定性增强的新型小型带阻频率选择表面的设计

本文介绍了工作在2.4 GHz的小型2.5维频率选择表面（FSS）带阻滤波器。拟议的FSS在FR-4基板的顶层和底层包含弯曲线以及金属贴片，并使用垂直通孔连接顶层和底层。所提出的配置单元电池的尺寸减小显著至0.040 λ ₀ ×0.040 λ ₀（其中，λ ₀是在2.4 GHz所需频率下的自由空间波长。另外，这种元件布置有助于实现140％的分数带宽。测得的-10 dB带宽为1至4.5 GHz。拟议的FSS对偏振不敏感，并且角度稳定性高（最大75°）。还提供了该FSS的等效电路模型（ECM）和相关的表面电流分布，以了解其工作机理。设计性能验证是通过功能原型的构建和测试进行的。全波模拟，ECM和测量结果表明了一个有希望的协议。