An ultraminiaturized frequency selective surface (FSS) based on 2.5-D convoluted structure is proposed. 2-D convoluted lines in the form of square spirals are incorporated with vertical vias to give a unit cell size which is only 2.7% of the free-space wavelength at resonance frequency of 2.8 GHz. Transverse-electric (TE) and transverse-magnetic (TM) resonators are combined to synthesize the proposed FSS unit cell resulting in a polarization-independent 2.5-D FSS. Moreover, the designed FSS provides a stable frequency response for incidence angles, up to 75°, for both the TE and TM polarizations. An equivalent circuit model is also developed to provide physical insights into the working mechanism of the proposed FSS. Transmission characteristics of the FSS are analyzed using full-wave simulations and equivalent circuit modeling. A prototype FSS is fabricated and measured utilizing ${S}$ -band waveguide setup where a good consistency between the measured and simulated frequency responses validates the design process.

中文翻译：

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使用 2.5D 回旋方形螺旋设计和分析超小型化 FSS

提出了一种基于 2.5 维卷积结构的超小型化频率选择表面 (FSS)。方形螺旋形式的 2-D 回旋线与垂直通孔相结合，以提供仅 2.8 GHz 谐振频率下自由空间波长的 2.7% 的单元尺寸。横向电 (TE) 和横向磁 (TM) 谐振器相结合以合成所提出的 FSS 晶胞，从而产生与极化无关的 2.5-D FSS。此外，设计的 FSS 为 TE 和 TM 极化的入射角提供稳定的频率响应，最高可达 75°。还开发了等效电路模型，以提供对所提出的 FSS 工作机制的物理见解。使用全波仿真和等效电路建模来分析 FSS 的传输特性。