A metasurface is highly useful for improving the performance of patch antennas and reducing their size due to their inherent and unique electromagnetic properties. In this research work, we design a wideband bandstop reflector-based frequency selective surface (FSS). It consists of a periodic array of circular shape metallic rings with four stubs. The FSS unit cell resonates over a frequency band from 7.2 to 9.2 GHz and has excellent stability under different polarizations and incident angles. A microstrip patch-based isolated multiple input multiple output (MIMO) antenna is designed that operates over a frequency band of 7.9GHz to 8.7 GHz. The MIMO antenna and FSS are printed on the one face of a substrate. The radiation performance such as gain and directivity of the antenna is improved due to parasitic radiation of the surface and coherent- superposition of energy in the far-field, between the antenna and FSS unit cells. Where the other parameters such are efficiency, radiation pattern and isolation are well preserved. The designed structure shows low complexity during fabrication. The simulated and experimental results confirm the predicted antenna performance and gain enhancement.

中文翻译：

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用于隔离多输入多输出天线增益增强的角稳定频率选择表面

由于其固有和独特的电磁特性，超表面对于提高贴片天线的性能和减小其尺寸非常有用。在这项研究工作中，我们设计了一种基于宽带带阻反射器的频率选择表面 (FSS)。它由带有四个短截线的圆形金属环的周期性阵列组成。FSS 晶胞在 7.2 至 9.2 GHz 的频带内谐振，并在不同的偏振和入射角下具有出色的稳定性。设计了一种基于微带贴片的隔离式多输入多输出 (MIMO) 天线，可在 7.9GHz 至 8.7GHz 的频段上运行。MIMO 天线和 FSS 印在基板的一个面上。由于天线和 FSS 单元之间的表面寄生辐射和远场中能量的相干叠加，天线的增益和方向性等辐射性能得到改善。其他参数如效率、辐射模式和隔离度都得到了很好的保留。设计的结构在制造过程中显示出低复杂性。模拟和实验结果证实了预测的天线性能和增益增强。