This paper proposes an array antenna with high isolation for MIMO application. Two tightly coupled microstrip patch pairs are proposed as array element with two rectangular stubs connected. By adjusting the position and width of the stubs, good resonant frequency matching can be achieved, and isolation can be effectively improved across the operating frequency band. Furthermore, 1 × 2 and 1 × 4 arrays with only 0.04 wavelength space between the edges are constructed for MIMO application. By adding an open-loop resonators (OLR) and slots in the metal reflector, the isolation between adjacent ports can be improved to 26 dB. In order to verify the feasibility of the proposed array antenna, the array antenna has been simulated, processed and tested, respectively. The simulation and measurement agree well and show the isolation more than 25 dB for all ports. The proposed structure has great potential in practical MIMO applications.

中文翻译：

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采用紧密耦合微带贴片对设计的高隔离 MIMO 天线

本文提出了一种用于 MIMO 应用的高隔离度阵列天线。提出两个紧密耦合的微带贴片对作为阵列元件，并连接两个矩形短截线。通过调整短截线的位置和宽度，可以实现良好的谐振频率匹配，并且可以有效提高整个工作频段的隔离度。此外，为 MIMO 应用构建了边缘之间仅 0.04 波长间隔的 1 × 2 和 1 × 4 阵列。通过在金属反射器中添加开环谐振器 (OLR) 和槽，相邻端口之间的隔离度可提高至 26 dB。为了验证所提出的阵列天线的可行性，对阵列天线分别进行了仿真、加工和测试。仿真和测量结果非常吻合，所有端口的隔离度均超过 25 dB。所提出的结构在实际 MIMO 应用中具有巨大的潜力。