In this letter, a novel multiple-input–multiple-output (MIMO) antenna operating at 3500 MHz band is presented for 5G mobile terminals. The proposed antenna includes four blocks. Each block consists of two face-to-face elements with total size of 25 × 3.5 mm2. Rather than excited separately, the two elements are excited simultaneously. Pattern diversity is achieved by using in-phase and out-of-phase signals. A compact two-port feed network is designed to provide the required feed signals. The measured bandwidth for the two ports is 750 MHz (3.06–3.81 GHz) and 340 MHz (3.33–3.67 GHz), which is sufficient to cover the 3400–3600 MHz band. The port isolation is higher than 14 dB in the overlapping bandwidth.

中文翻译：

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基于方向图分集的5G移动终端高隔离度MIMO天线设计

在这封信中，介绍了一种适用于 5G 移动终端的新型多输入多输出 (MIMO) 天线，工作频率为 3500 MHz。建议的天线包括四个块。每个块由两个面对面的元素组成，总大小为 25 × 3.5 mm2。这两个元素不是单独激发，而是同时激发。模式多样性是通过使用同相和异相信号来实现的。紧凑的两端口馈电网络旨在提供所需的馈电信号。两个端口的实测带宽分别为 750 MHz (3.06–3.81 GHz) 和 340 MHz (3.33–3.67 GHz)，足以覆盖 3400–3600 MHz 频段。重叠带宽中端口隔离度高于14dB。