In this communication, a metasurface-based decoupling method (MDM) is proposed to reduce the mutual couplings at two independent bands of two coupled multiple-input-multiple-output (MIMO) antennas. The metasurface superstrate is composed of pairs of non-uniform cut wires with two different lengths. It is compact in size and effective in decoupling two nearby dual-band patch antennas that are strongly coupled in the H-plane with the edge-to-edge spacing of only 0.008 wavelength at low-frequency band (LB). The antenna is fabricated and measured and the results show that the isolation between two dual-band antennas can be improved to more than 25 dB at both 2.5–2.7 GHz and 3.4–3.6 GHz bands, while their reflection coefficients remain to be below −10 dB after the metasurface superstrate is introduced. Moreover, the total efficiency is improved by about 15% in the low band and the envelope correlation coefficient (ECC) between the two antennas is reduced from 0.46 to 0.08 at 2.6 GHz and 0.08 to 0.01 at 3.5 GHz. The proposed method can find plenty of applications in dual-band MIMO and 5G communication systems.

中文翻译：

---

基于双频超表面的两根密排双频天线去耦方法

在这种通信中，提出了一种基于超表面的解耦方法（MDM）来减少两个耦合多输入多输出（MIMO）天线在两个独立频段上的互耦合。超表面覆层由具有两种不同长度的非均匀切割线对组成。它尺寸紧凑，可有效地去耦两个附近的双频段贴片天线，这些天线在 H 平面中强耦合，低频段 (LB) 的边到边间距仅为 0.008 波长。天线的制作和测量结果表明，两个双频段天线之间的隔离度在 2.5-2.7 GHz 和 3.4-3.6 GHz 频段都可以提高到 25 dB 以上，而它们的反射系数保持在 -10 以下引入超表面覆层后的 dB。而且，低频段的总效率提高了约 15%，两个天线之间的包络相关系数 (ECC) 在 2.6 GHz 时从 0.46 降至 0.08，在 3.5 GHz 时从 0.08 降至 0.01。所提出的方法可以在双频 MIMO 和 5G 通信系统中找到大量应用。