Maintaining the compact form of 5G smartphones while accommodating millimeter-wave (mm-wave) bands is a significant challenge due to the substantial frequency difference. To address this issue, we’ve introduced an super-compact 4-port dual-band multiple-input, multiple-output (MIMO) antenna that utilizes a metamaterial-inspired electromagnetic bandgap (EBG) structure. This design minimizes mutual coupling (MC) and handles a wide frequency range effectively. The 4-port MIMO antenna is constructed on a Rogers TMM4 substrate, with overall dimensions of 17.76 × 17.76 mm². It incorporates four planar patch antennas positioned at the corners, arranged perpendicularly to each other. Each antenna element is designed for dual-band operation at 28/38 GHz, featuring a rectangular patch with four rectangular slots and a full ground plane. The gap between these patches measures 0.5 λo, and an EBG is included to minimize MC among the MIMO antenna elements efficiently and cost-effectively. Both simulation and measurement results show a substantial reduction in mutual coupling between the array elements, ranging from −25 to −90 dB. Consequently, this enhances the envelope correlation coefficient (ECC) and improves the total active reflection coefficient (TARC), mean effective gain (MEG), and diversity gain (DG). An in-depth time-domain analysis is proposed to confirm the radiation efficiency of the proposed MIMO antenna design. Furthermore, specific absorption rate (SAR) analysis affirms the suitability of this MIMO antenna for 5G cellular devices operating within the target frequency band.

由于频率差异巨大，保持 5G 智能手机的紧凑外形，同时适应毫米波 (mm-wave) 频段是一项重大挑战。为了解决这个问题，我们推出了一款超紧凑型 4 端口双频多输入多输出 (MIMO) 天线，该天线采用超材料启发的电磁带隙 (EBG) 结构。这种设计最大限度地减少了互耦 (MC)，并有效地处理较宽的频率范围。4端口MIMO天线构建在Rogers TMM4基板上，整体尺寸为17.76 × 17.76 mm²。它包含四个位于角落的平面贴片天线，彼此垂直排列。每个天线元件均设计用于 28/38 GHz 的双频段操作，具有带有四个矩形槽和完整接地平面的矩形贴片。这些贴片之间的间隙为 0.5 λo，并且包含 EBG，可有效且经济高效地最大限度地减少 MIMO 天线元件之间的 MC。仿真和测量结果均显示阵列单元之间的互耦合大幅降低，范围为-25 至-90 dB。因此，这增强了包络相关系数（ECC）并改善了总有源反射系数（TARC）、平均有效增益（MEG）和分集增益（DG）。提出了深入的时域分析来确认所提出的 MIMO 天线设计的辐射效率。此外，比吸收率 (SAR) 分析证实了该 MIMO 天线适用于在目标频段内运行的 5G 蜂窝设备。