ABSTRACT This paper presents a five (05)-port proximity coupled monostatic patch antenna having four (04) linearly co-polarized ports (same polarization for two-transmit and two-receive ports) for 2.4 GHz in-band full duplex (IBFD) 2-order MIMO (multi-input multi-output) wireless applications. The employed differential receive mode mechanism and single-tap self-interference cancellation (SIC) circuit achieves high isolation between transmit (Tx) and receive (Rx) ports for IBFD operation. The fifth port is dual polarized with respect to the first four (04) ports to provide intrinsic isolation through polarization diversity. The implemented antenna system provides 10 dB return-loss bandwidth of more than 200 MHz for all five ports. The measured MIMO isolation (Tx-Tx ports and Rx-Rx ports) is better than 15 dB and full duplex Tx-Rx isolation ≈ 20 dB between linearly co-polarized ports for 200 MHz bandwidth. Moreover, the interport isolation between Tx ports (Rx ports) and dual polarized port (port 5) > 30 dB (25 dB) in 200 MHz bandwidth in addition to better than 60 dB (27 dB) peak isolation. To the best of our knowledge, it is the first type of such monostatic antenna with multiple co-polarized and dual polarized ports for full duplex MIMO applications.

中文翻译：

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具有改进的端口间隔离的多端口单基地天线系统，适用于 2.4GHz 全双工 MIMO 应用

摘要 本文介绍了一种用于 2.4 GHz 带内全双工 (IBFD) 的五 (05) 端口邻近耦合单基地贴片天线，具有四 (04) 个线性共极化端口（两个发送和两个接收端口的极化相同） 2 阶 MIMO（多输入多输出）无线应用。所采用的差分接收模式机制和单抽头自干扰消除 (SIC) 电路实现了传输 (Tx) 和接收 (Rx) 端口之间的高度隔离，以进行 IBFD 操作。第五个端口相对于前四个 (04) 端口进行双极化，以通过极化分集提供内在隔离。实施的天线系统为所有五个端口提供超过 200 MHz 的 10 dB 回波损耗带宽。测得的 MIMO 隔离（Tx-Tx 端口和 Rx-Rx 端口）优于 15 dB，全双工 Tx-Rx 隔离在 200 MHz 带宽的线性同极化端口之间约为 20 dB。此外，在 200 MHz 带宽中，Tx 端口（Rx 端口）和双极化端口（端口 5）之间的端口间隔离度 > 30 dB (25 dB)，并且峰值隔离度优于 60 dB (27 dB)。据我们所知，它是第一种用于全双工 MIMO 应用的具有多个共极化和双极化端口的单基地天线。