Jose Alfredo Tirado-Mendez, Hildeberto Jardon-Aguilar, Ruben Flores-Leal, Arturo Rangel-Merino, Angel Perez-Miguel, Ricardo Gomez-Villanueva
Instituto Politécnico Nacional, Electrical Engineering Department, SEPI-ESIME-Zacatenco, Av. IPN S/N, Edif. 5., Ciudad de México 07300, Mexico.
CINVESTAV-IPN, Telecommunications Section, Av. IPN 2508, San Pedro Zacatenco, Ciudad de México 07360, Mexico.
Sensors (Basel). 2024 Sep 27;24(19):6266. doi: 10.3390/s24196266.
This article presents a symmetrical reduced-size eight-element MIMO antenna array with high electromagnetic isolation among radiators. The array utilizes easy-to-build techniques to cover the n77 and n78 new radio (NR) bands. It is based on an octagonal double-negative metamaterial split-ring resonator (SRR), which enables a size reduction of over 50% for the radiators compared to a conventional disc monopole antenna by increasing the slow-wave factor. Additionally, due to the extreme proximity between the radiating elements in the array, the modal significance () method was employed to identify which propagation modes had the most impact on the electromagnetic coupling among elements. This approach aimed to mitigate their effect by using an electromagnetic barrier, thereby enhancing electromagnetic isolation. The electromagnetic barriers, implemented with strip lines, achieved isolation values exceeding 20 dB for adjacent elements (<0.023 λ) and approaching 40 dB for opposite ones (<0.23 λ) after analyzing the surface current distribution by the method. The elements are arranged in axial symmetry, forming an octagon with each antenna port located on a side. The array occupies an area of 0.32 λ at 3.5 GHz, significantly smaller than previously published works. It exhibits excellent performance for MIMO applications, demonstrating an envelope correlation coefficient () below 0.0001, a total active reflection coefficient () lower than -10 dB for various incoming signals with random phases, and a diversity gain () close to 20 dB.
本文介绍了一种对称的小型八元MIMO天线阵列，其辐射器之间具有高电磁隔离。该阵列采用易于构建的技术来覆盖n77和n78新无线电（NR）频段。它基于八角形双负超材料裂环谐振器（SRR），通过增加慢波因子，与传统盘状单极天线相比，可使辐射器尺寸减小超过50%。此外，由于阵列中辐射元件之间的距离极近，采用模态显著性（）方法来确定哪些传播模式对元件间的电磁耦合影响最大。该方法旨在通过使用电磁屏障减轻其影响，从而增强电磁隔离。通过带状线实现的电磁屏障，在利用方法分析表面电流分布后，相邻元件（<0.023λ）的隔离值超过20dB，相对元件（<0.23λ）的隔离值接近40dB。元件呈轴对称排列，形成一个八边形，每个天线端口位于一条边上。该阵列在3.5GHz时占用面积为0.32λ，明显小于先前发表的作品。它在MIMO应用中表现出优异的性能，包络相关系数（）低于0.0001，对于具有随机相位的各种入射信号，总有源反射系数（）低于-10dB，分集增益（）接近20dB。
