A circularly polarized (CP) multiple-input multiple-output (MIMO) antenna with wideband operation and high isolation characteristics is presented. The proposed antenna is first designed with two diagonal slotted square patches and then, four parasitic elements are utilized to significantly improve the antenna performances. Notably, besides enhancing the operating bandwidth and the gain radiation, the parasitic elements also contribute to reduce the mutual coupling between the MIMO elements. The measurements demonstrate that the proposed two-element MIMO antenna with edge-to-edge spacing of 0.09λ_o and profile of 0.05λ_o at the center operating frequency has operating bandwidth of 12.8% (5.1–5.8 GHz) and high isolation of better than 22 dB. The antenna also achieves high gain of better than 7.5 dBic and good diversity performances. Compared to other CP MIMO antennas reported in literature, our design possesses several exclusive features including wideband operation, high gain, very small edge-to-edge element spacing as well as low-profile configuration.

提出了一种具有宽带工作和高隔离特性的圆极化（CP）多输入多输出（MIMO）天线。所提出的天线首先被设计为具有两个对角缝隙的方形贴片，然后利用四个寄生元件来显着提高天线性能。值得注意的是，除了增加工作带宽和增益辐射之外，寄生元件还有助于减少MIMO元件之间的相互耦合。测量表明，该两元件MIMO天线0.09边缘到边缘间距λ _ö和0.05轮廓λ _ö中心工作频率处的工作带宽为12.8％（5.1–5.8 GHz），隔离度优于22 dB。该天线还实现了优于7.5 dBic的高增益和良好的分集性能。与文献中报道的其他CP MIMO天线相比，我们的设计拥有多个专有功能，包括宽带操作，高增益，极小的边到边元素间距以及低剖面配置。