ABSTRACT In this paper, a dual-band circular polarised (CP), Multiple Input Multiple Output (MIMO) antenna with bi-directional polarisation is presented. Designed antenna is operating at two frequency bands i.e. 5.4 GHz–6.2 GHz and 7.0 GHz–7.4 GHz. A rectangular dielectric resonator (DR) is excited by two ports for designing an MIMO antenna system. To generate the Circular polarisation, ground plane is modified by etching an inverted Z-shaped slot. The fundamental mode , and higher order mode , are generated in the antenna structure due to the specified geometry which excites the circular polarisation. 3-dB axial ratio (AR) bandwidth of 300 MHz (5.7 GHz–6.0 GHz) and 200 MHz (7.0 GHz–7.2 GHz) is obtained for the lower and upper bands, respectively. Maximum isolation is 19 dB, and 15 dB for the targeted bands have been achieved. S-parameters, gain and radiation pattern are measured to authenticate the simulated results. Envelope correlation, diversity gain, mean effective gain and channel capacity loss are calculated from the measured parameters; their values lie within the optimum range. Results show that antenna is suitable for WLAN 5.5/5.8 GHz and X-band downlink communication at 7.0 GHz.

中文翻译：

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基于矩形 DR 的双频段 CP-MIMO 天线，具有倒 Z 形槽

摘要 在本文中，提出了一种具有双向极化的双频带圆极化 (CP)、多输入多输出 (MIMO) 天线。设计的天线工作在两个频段，即 5.4 GHz–6.2 GHz 和 7.0 GHz–7.4 GHz。矩形介质谐振器 (DR) 由两个端口激发，用于设计 MIMO 天线系统。为了产生圆极化，通过蚀刻倒 Z 形槽来修改接地平面。由于激发圆极化的特定几何形状，在天线结构中产生基模和高阶模。分别为低频段和高频段获得了 3-dB 轴比 (AR) 带宽，分别为 300 MHz (5.7 GHz–6.0 GHz) 和 200 MHz (7.0 GHz–7.2 GHz)。最大隔离度为 19 dB，目标频段的隔离度为 15 dB。S 参数，测量增益和辐射方向图以验证模拟结果。根据测量参数计算包络相关、分集增益、平均有效增益和信道容量损失；它们的值都在最佳范围内。结果表明，该天线适用于 WLAN 5.5/5.8 GHz 和 7.0 GHz 的 X 波段下行链路通信。