In this paper, a cavity-backed semi-circular antenna with rectangular slot for MIMO (multiple-input multiple-output) systems is presented. The proposed MIMO antenna comprises two rectangular slots etched on the ground plane and excited by two microstrip transmission lines. The substrate integrated waveguide (SIW) is integrated to enhance the isolation between the two antenna elements. The obtained results show that the antenna operates around 5.8 GHz with an impedance bandwidth between 5.65 and 5.9 GHz, with S₁₁ ≤ −10 dB, which is suitable for WLAN (wireless local area networking) applications. The fractional bandwidth of the reference MIMO antenna is 4.13%, while for the SIW MIMO case attains 4.31%. Moreover, the integration of SIW resonators leads to an enhancement of the isolation from 17.7 dB (reference antenna) to 30 dB. The achieved gain is about 5.6 dBi at the resonance frequency 5.8 GHz. The envelope correlation coefficient (ECC) is lower than 7 × 10⁻⁵ across the operating bandwidth. The simulated results are in good agreement with the experimental ones. The fabricated antenna exhibits very acceptable radiation performances compared to the conventional one.

中文翻译：

---

使用衬底集成波导技术增强 MIMO 腔天线的隔离度

在本文中，提出了一种用于 MIMO（多输入多输出）系统的具有矩形缝隙的背腔半圆形天线。所提出的 MIMO 天线包括蚀刻在地平面上并由两条微带传输线激励的两个矩形槽。集成基板集成波导 (SIW) 以增强两个天线元件之间的隔离度。获得的结果表明，天线工作在 5.8 GHz 附近，阻抗带宽在 5.65 和 5.9 GHz 之间，S ₁₁ ≤ −10 dB，适用于WLAN（无线局域网）应用。参考 MIMO 天线的部分带宽为 4.13%，而 SIW MIMO 情况下达到 4.31%。此外，SIW 谐振器的集成导致隔离度从 17.7 dB（参考天线）提高到 30 dB。在 5.8 GHz 的谐振频率下获得的增益约为 5.6 dBi。包络相关系数 (ECC)在整个工作带宽内低于 7 × 10 ^-5。模拟结果与实验结果吻合较好。与传统天线相比，制造的天线表现出非常可接受的辐射性能。