This paper presents a compact 5G multiple‐input multiple‐output (MIMO) microstrip antenna with isolation enhancement based on a slotted complementary split‐ring resonator (SCSRR) and the theory of characteristic modes (TCMs). The metamaterial unit consists of three CSRR connected by extra slots. These added slots improve significantly the rejection response in terms of bandwidth and suppression. The dispersion diagram analysis is introduced to show the filtering characteristics of the band‐gap structure before and after adding these additional slots. The TCM is employed to investigate the behavior of this 5G MIMO antenna before and after adding the slotted CSRR. The TCM is also applied to the MIMO antenna system to build up a precise methodology that can foresee whether the isolation can be upgraded further or not. The slotted CSRR is inserted meticulously in specific locations to block the coupling modes and almost does not affect the results of the noncoupling modes to improve the isolation remarkably. With this slotted CSRR, a 27‐dB reduction in the mutual coupling between the two patch antennas is achieved. The whole design has been simulated utilizing the Microwave Studio CST ver. 18 simulator. The antenna being proposed is highly efficient and suitable for 5G wireless communication.

中文翻译：

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使用超材料和特征模式理论增强5G多输入多输出微带贴片天线的隔离度

本文介绍了一种紧凑的5G多输入多输出（MIMO）微带天线，具有基于缝隙互补开口环谐振器（SCSRR）和特征模式理论（TCM）的隔离增强功能。超材料单元由通过额外插槽连接的三个CSRR组成。这些增加的时隙在带宽和抑制方面显着改善了拒绝响应。引入了色散图分析，以显示在添加这些其他时隙之前和之后带隙结构的滤波特性。在添加时隙CSRR之前和之后，采用TCM来研究此5G MIMO天线的行为。TCM还应用于MIMO天线系统，以建立一种精确的方法，可以预见隔离是否可以进一步升级。开槽的CSRR被精心地插入特定位置以阻止耦合模式，并且几乎不影响非耦合模式的结果，从而显着改善了隔离度。使用此时隙CSRR，可将两个贴片天线之间的互耦降低27 dB。整个设计已使用Microwave Studio CST ver。进行了仿真。18模拟器。提出的天线非常高效，适合5G无线通信。