This article presents a fully planar ultrawideband wide-angle scanning tightly coupled array. A tightly coupled element, which has a low input resistance, is used as the basic array element. The element can be fed by a simple microstrip-to-coaxial transition, obviating the need for an additional impedance transform structure. To improve the scan performance of the array in both the E- and H-planes, a polarization-sensitive frequency-selective surface (FSS) structure, whose effective dielectric constant for the TM mode incidence wave and TE mode incidence wave can be changed, respectively, by different structural parameters, is designed to serve as the wide-angle impedance matching (WAIM) layer. The FSS structure is printed on the superstrate dielectric directly without an additional dielectric layer, resulting in a low-cost array. The proposed array can work in 3.7:1 bandwidth with voltage standing wave ratio (VSWR) < 3 for E-plane scanning up to 75° and H-plane scanning up to 60°. Based on the designed unit cell, an $11\times11$ prototype is fabricated and measured. The measured results of the fabricated array show good agreement with simulations, proving the feasibility of the design.

中文翻译：

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加载偏振敏感频率选择表面结构的平面超宽带广角扫描阵列

本文介绍了一种全平面超宽带广角扫描紧耦合阵列。具有低输入电阻的紧密耦合元件用作基本阵列元件。该元件可以通过一个简单的微带线到同轴转换来馈电，从而无需额外的阻抗变换结构。为了提高阵列在 E 平面和 H 平面的扫描性能，偏振敏感频率选择表面 (FSS) 结构可以改变 TM 模式入射波和 TE 模式入射波的有效介电常数，分别通过不同的结构参数设计作为广角阻抗匹配（WAIM）层。FSS 结构直接印刷在上层电介质上，无需额外的电介质层，从而形成低成本的阵列。所提出的阵列可以在 3.7:1 的带宽下工作，电压驻波比 (VSWR) < 3，E 平面扫描高达 75°，H 平面扫描高达 60°。基于设计的单元电池，制造和测量了一个 $11\times11$ 的原型。制造的阵列的测量结果与模拟结果吻合良好，证明了设计的可行性。