应用于物联网MIMO天线的双频谐振解耦结构

提出了一种用于双频MIMO天线的谐振器去耦结构。通过双频单极子MIMO天线对该解耦结构进行验证。双频单极子天线分别工作在低频2.4GHz和高频5.8GHz。 双频解耦结构在低频段主要是采用两个反向的π型微带谐振器解耦,高频段主要是采用π型缝隙谐振器解耦。天线采用微带线馈电,解耦谐振器与天线地板印刷在PCB同一面,结构紧凑易于与系统集成,可以广泛应用于物联网通信系统中。 实测结果：双频谐振器去耦结构实现隔离度高于22dB,单极子天线阻抗带宽分别为2.0GHz-3.0GHz和5.0-6.0GHz（S11<-10dB）,低频段增益最大增益点1.5dBi,高频段最大增益点3dBi。     

面向毫米波MIMO的方向图去耦印刷偶极子天线

针对MIMO(Multiple-Input Multi-Output)多天线系统中因耦合导致的天线单元辐射方向图畸变问题,提出了一种基于短路枝节的方向图去耦方法。在偶极子辐射臂和地板之间引入的短路枝节可调节耦合单元辐射臂上感应电流的幅度和相位,进而对天线单元畸变的辐射方向图完成波束纠偏和凹陷修复,实现方向图去耦。在5G毫米波n260频段(37～40 GHz)设计、制作了1×4 MIMO印刷偶极子天线实物,实测方向图的最大辐射方向被纠正到正天顶,实测端口隔离度大于23.5 dB。实测与仿真结果吻合良好,验证了提出的方向图去耦方法的有效性。提出的方向图去耦的1×4毫米波MIMO印刷偶极子天线性能良好、易于实现,可应用于毫米波MIMO系统。     

应用于5G的高隔离宽带MIMO手机天线设计

为满足5G移动通信的需求,文中设计了一款宽频带天线单元,并基于此分别提出了4×4和8×8多输入多输出(MIMO)手机天线。两个天线单元“背对背”紧密放置组成一个自去耦天线对,4×4 MIMO手机天线由两个天线对构成。天线结构简单、尺寸紧凑,可以覆盖3.3～6.6 GHz的工作频带,隔离度优于15.5 d B。在4×4 MIMO手机天线的基础上,保持天线单元结构不变,通过合理布局,将四个天线单元与天线对内的天线单元分别“背对面”放置构成8×8 MIMO手机天线。仿真和测试结果表明,该天线在3.4～6.1 GHz的工作频带内各天线单元间隔离度优于15 d B,满足实际工程需求,同时,文中分析讨论了单手持模式下的天线性能。     

一种高隔离度的双倒L形双频MIMO天线设计

研究了一种微带线馈电的双倒L形双频MIMO印刷天线结构,通过在倒L单极子结构上加载一条倒L形地板枝节,实现了天线的双频特性;通过在天线单元之间加载一条T形去耦枝节,有效提高了天线单元之间的隔离度。实验结果表明,天线在S11≤-10 dB时,工作频段分别为2.39~2.53 GHz和4.92~6.15 GHz,相对带宽分别为5.7%和22.2%,工作频段内隔离度均大于18 dB。此外,天线整体辐射特性较好,结构简单并易于制作,可应用于WLAN无线通信系统。     

5G新体制天线技术研究

通过对现今5G技术的发展趋势和发展瓶颈进行分析,提炼出在5G MIMO天线技术中最为重要的耦合减小技术.分别介绍两大类新体制天线技术,包括基于耦合谐振器去耦网络的紧耦合终端天线、基于超材料(超表面)的MIMO、Massive MIMO天线阵耦合减小及性能提升技术.通过无源参数、有源参数和MIMO参数的测试和评估,证实这两类新体制天线在5G中的明显优势和广阔的应用场景.     

基于空间分集的MIMO雷达目标跟踪算法研究

针对基于空间分集的多输入多输出(MIMO)雷达多发多收的特殊结构,建立了基于逆协方差形式扩展卡尔曼滤波算法的MIMO雷达目标跟踪滤波模型,分析了影响算法滤波精度的4个因素,分别为信噪比、信号带宽、天线数以及天线与目标间的位置关系。通过使目标位置状态估计均方误差最小,在特定天线数条件下利用数值方法得到了使滤波精度达到最优的天线放置形式。仿真实验给出了不同信噪比、信号带宽、天线数以及天线与目标间不同位置关系时的MIMO雷达跟踪性能。     

基于耦合谐振去耦网络的双频近距天线解耦

提出了一种基于耦合谐振的双频去耦网络,并将其应用于一对二元双频近距单极子天线的解耦中。对去耦网络满足的去耦条件和匹配条件进行了推导;将网络以双频耦合谐振器的结构加以实现,提取了该结构的等效电路;基于去耦网络,设计了一副工作于WLAN 2. 45/5. 25 GHz 的二元双频近距单极子天线,天线阵元边缘间的距离为2. 45 GHz 时的0. 0735 λ0 和5. 25 GHz 时的0. 1575 λ0 ( λ0 为自由空间工作波长)。对未解耦天线和解耦后天线进行了仿真和测试,结果表明,通过加载去耦网络,2. 45 GHz 和5. 25 GHz 处的隔离度分别提高了24. 52 dB 和26. 57dB,且在两个频段内阻抗匹配良好、总的效率提高、通道容量增大。提出的去耦网络适用性强,结构紧凑且解耦高效,可应用于无线终端MIMO 技术中。     

窄带波束信道MIMO系统的容量分析

最近的研究表明,多输入多输出(MIMO)技术在不增加功率和带宽消耗的情况下具有大幅提高无线通信速率的潜力.在传统的MIMO系统(称为天线信道MIMO系统)中,多个接收天线的输出被直接选作多输出信号.提出了波束信道MIMO系统的结构.在波束信道MIMO系统中,多个波束的输出被选作多输出信号.基于阵列方向响应矢量,提出了窄带MIMO信道冲激响应矩阵的仿真算法.基于提出的信道冲激响应矩阵算法,给出了天线信道MIMO系统和波束信道MIMO系统容量极限的分析算法.理论分析和仿真结果都表明:波束信道能够提高信噪比(SNR),降低信道间的互相关性,因此波束信道MIMO系统比天线信道MIMO系统具有更大的容量极限.     

一种提高微带MIMO 天线端口隔离度的新方法

多输入多输出(MIMO) 无线通信系统已经成为提高通信系统可靠性和数据传输速率的有效技术。MIMO 通信系统中,终端天线的性能对系统通信容量的提升至关重要。为了提高天线端口隔离度,提出了一种在微带天线辐射贴片上加载缝隙阵列实现天线极化分集,提高天线隔离度的方法,并且将这种方法应用于两个2 单元微带MIMO 天线设计中,取得了良好的效果。缝隙阵列加载不但抑制了微带MIMO 天线单元间的耦合,而且产生了更多谐振频点,改善了高频谐振频点畸变的天线辐射方向图,并且天线尺寸也得到了很大的减缩。最后对比分析了设计的两个微带MIMO 天线,实测结果与仿真计算比较可知,在工作带宽内,单元天线间耦合得到了非常有效的抑制。这种在平面天线辐射贴片加载缝隙阵列改变天线极化方向的技术可以很好地用来抑制多天线系统中单元天线间的耦合,而且对天线的其他性能不会造成影响。     

MIMO无线传输技术综述

MIMO无线传输技术是通信领域的一项重要技术突破,它能在不增加带宽与功率的情况下成倍地提高无线通信系统的容量和频谱效率,堪称新一代无线通信系统中的关键技术之一,近年来引起了人们的广泛关注与研究兴趣。回顾无线移动通信的发展历程,概述天线分集技术与智能天线技术,剖析MIMO无线传输技术的原理与国内外研究现状:传统单天线系统向多天线系统演进、智能天线向多天线系统演进、MIMO无线传输技术的原理、MIMO系统中的分集与复用、MIMO无线信道建模、MIMO系统中的多天线设计等,为深入认识与进一步研究MIMO无线传输技术奠定基础。     

基于模式抵消法的耦合环集成MIMO 天线

针对移动终端设备中MIMO 天线尺寸受限的问题,文中基于模式抵消法提出了一种耦合环结构的集成 MIMO 天线。在传统环天线结构中增加断点以调节共模频率使其与差模频率匹配,从而实现集成环天线的自解耦,无 需任何额外的解耦结构。仿真和测试结果表明,该耦合环集成MIMO 天线的-6dB 阻抗带宽为3.3~5.0GHz,隔离度 大于10 dB,天线的测试效率为52%~74%,包络相关系数(ECC)<0.15。此外,文中还进一步讨论了将该天线应用于实 际的5G 移动终端设备中。相比于已有研究,该设计具有结构简单、无需额外解耦结构、宽带等性能优势,具有较大的 工业应用前景。     

A triband swastika shaped patch antenna with reduced mutual coupling for wireless mimo systems

A novel compact Swastika shaped patch antenna is designed in the present work, which can be used for Multiple Input Multiple Output (MIMO) systems. The proposed two element MIMO system resonates at a triband of 3.3 GHz, 5.8 GHz, and 7.1 GHz with an improved impedance bandwidth of 37% and a reduced mutual coupling of ?33 dB. These results are better compared to a normal E shaped patch antenna designed with same size and thickness, achieved without using any additional decoupling methods. A 2??2 MIMO system employing the Swastika shaped patch antennas is analyzed using computational electromagnetic ray tracing software for an indoor environment. The results show an improvement in the capacity compared to a 2??2 MIMO system developed with dipole antennas. The proposed antenna is a good choice for MIMO systems operating for several Ultra WideBand (UWB) applications.     

基于介质片加载实现MIMO介质谐振器天线解耦

提出了一种通过在介质谐振器(DR)上表面侧边加载介质片(DS)来实现1×2 MIMO介质谐振器天线(DRA)解耦的新方法。1×2 MIMO DRA采用双层介质基板结构以优化阻抗匹配特性和辐射特性,两DR的边到边间距为0,天线工作在毫米波频段。所加载的DS使得DR内的场重新分布并向DS加载区域以及DS内集中,从而减弱耦合到另一DR单元的场强以实现解耦效果。基于ANSYS HFSS的仿真结果表明天线的-10 dB阻抗匹配带宽为25.6%(22.75～29.43 GHz),带内最大实现了30 dB的隔离度的增强。     

Broadband sub-6 GHz flower-shaped MIMO antenna with high isolation using theory of characteristic mode analysis (TCMA) for 5G NR bands and WLAN applications

A small size neutralization line integrated flower-shaped MIMO antenna is designed and analyzed for sub-6 GHz type 5G NR frequency bands like n79 (4400–5000 MHz), n78 (3300–3800 MHz), n77 (3300–4200 MHz), and WLAN (5150–5825 MHz) applications. The novel approach of theory of characteristic mode analysis (TCMA) is introduced to provide physical insight of the designed structure and its characteristics behavior. Due to the suggested modifications in the geometry, the isolation among the patches is greatly increased. The overall miniaturized dimension of the MIMO antenna is 25 × 40 mm². The edge-edge spacing among the elements is 0.0233λ. The prototype antenna is fabricated and measured that shows good agreement compared with simulated results. The designed MIMO antenna without the presence of decoupling structure offers an isolation of 28 dB, gain of 3.6 dBi, and radiation efficiency of 69.7% at the resonant frequency. The proposed MIMO antenna covers a broad range of frequency band from 3.296 to 5.962 GHz with −10 dB impedance bandwidth of 2666 MHz and maintains a good isolation of greater than 50 dB for the entire operating band. The tested radiation efficiency and gain are 85.3% and 6.22 dBi at 3.5 GHz. Moreover, the diversity parameters of the neutralization line integrated MIMO antenna, that is, channel capacity loss (CCL) isolation, mean effective gain (MEG), total active reflection coefficient (TARC) diversity gain (DG), and envelope correlation coefficient (ECC), are analyzed and discussed in this article.     

A miniaturized uniplanar MIMO antenna for n79/n46/millimeter-wave applications

This research suggests a compact uniplanar multiple-input multiple-output (MIMO) with four ports for n79/n46/millimeter-wave (mm-wave) applications. The size of the quad MIMO is only 30 × 30 × 0.8 mm³. MIMO system consists of four identical Z-shaped radiators and common ground on the same plane and no decoupling structures are used for isolation. The system covers the bandwidth of 1.9 GHz (4.4–6.3 GHz) with a mid-frequency of 5.6 GHz and also covers the high-band frequencies ranging from 18 to 30 GHz with a bandwidth of 12 GHz. The suggested quad MIMO is fabricated on an FR-4 board, and the measured outcomes are well in line with the simulated results. An isolation value of −11 dB has been achieved for mid-band frequency and −24 dB has been attained for mm-wave bands. Through the value of DG = 10 dB, ECC < 0.07, TARC < −3 dB, MEG < −5 dB, and the ratio of MEG = 1 dB, uniplanar quad MIMO shows acceptable MIMO diversity performance. The entire system was evaluated for the users' hand specific absorption rate (SAR) impacts and is within the limits. After the complete analysis of the miniature quad MIMO antenna, an 8-port, and a 16-port uniplanar MIMO are simulated for smartphone-sized dielectric substrates and the performances were examined. The suggested MIMO system provides an efficient single-layer MIMO antenna to 5G smartphones with high bandwidth and low SAR. The proposed quad MIMO systems are suitable for both the sub-6 GHz band and the mm-wave band.     

Co-located and space-shared multiple-input multiple-output antenna module and its applications in 12 × 12 multiple-input multiple-output systems

In this study, we developed a co-located and space-shared multiple-input multiple-output (MIMO) antenna module with a modular design and high integration level. The proposed antenna pair includes a half-wavelength loop antenna and a dipole-type antenna printed on the front and back sides of a compact modular board. Owing to their modal orthogonality, these two independent antenna elements are highly self-isolated and free of additional decoupling components, even though they are assembled at the same location and within the same space. Thus, the proposed antenna is attractive in 5G MIMO systems. Furthermore, the proposed co-located and space-shared MIMO antenna module was employed in a 5G smartphone to verify their radiation and diversity performances. A 12 × 12 MIMO antenna system was simulated and fabricated using the proposed module. Based on the results, the proposed module can be employed in large-scale MIMO antenna systems for current and future terminal devices owing to its high integration, compactness, simple implementation, and inherent isolation.     

具有双陷波特性的UWB-MIMO天线

提出了一款具有双陷波特性的紧凑型超宽带多输入多输出(ultra wideband multiple-input multiple-output, UWB-MIMO)天线. 天线由两个辐射元件组成,整体尺寸为41 mm×25 mm×1.6 mm. 通过在天线的接地平面中引入两个叠加的T型结构获得良好的隔离度;同时,通过在天线上刻蚀C型槽和U型槽实现双陷波特性,有效抑制了无线局域网(wireless local area networks, WLAN)和X波段通信卫星的干扰;并从表面电流分布的角度分析了陷波原理. 实验结果表明:所设计的MIMO天线的阻抗带宽为2.8~13.4 GHz,两个陷波频带分别为4.8~5.94 GHz和6.9~8.23 GHz;在整个工作带宽内,隔离度大于15 dB. 说明MIMO天线具有良好的辐射特性、稳定的增益和较低的包络相关系数(envelope correlation coefficient, ECC)(<0.1),适用于UWB-MIMO系统应用.     

紧凑型4×4单元超宽带MIMO缝隙天线设计

为了更好地实现移动终端天线小型化,提出了一种具有较高单元间隔离度的紧凑型超宽带（multiple input multiple output,MIMO）天线。该天线无需任何解耦网络,通过阶梯形缝隙结构来实现各个天线单元。采用的阶梯形缝隙天线不仅减少了天线的尺寸,而且具有定向辐射行为,从而形成较高的高隔离度。提出的天线尺寸为23×23mm3。测量结果表明,提出的超宽带MIMO天线在3 GHz-10.9 GHz频谱中能够产生较好的多向辐射特性（S11≤-10dB）,阻抗隔离大于20dB,包络相关系数和信道容量损耗的容许界限保证了良好的MIMO性能。     

Bi-directional UWB MIMO Antenna for Superior Spatial Diversity,and/or Multiplexing MIMO Performance

In this paper, a two-element UWB MIMO antenna with bi-directional radiation pattern is designed for superior UWB MIMO performance. The designed antenna adopts asymmetric coplanar waveguide ground feeding. The proposed antenna ECC is lower than the ECC of its omni-directional peer antenna. Simulated and measured ECC is lower than 0.016 over the entire ultra-wide bandwidth (3.1–10.6 GHz). The isolation between elements of the designed antenna is 20–25 dB exceeding the average in recently published works. The designed antenna has a diversity gain of almost 10 dB and average multiplexing efficiency of 85% over the entire ultra-wide bandwidth. The antenna preserves radiation efficiency higher than 0.96 and gain 3 dB. The diversity performance of the proposed UWB MIMO antenna is proven through real rich-multipath indoor environment measurements. Stationarity of the elected channel is evaluated through 100 successive measurements separated by a 3-min period for 5 h long. The measured spatial correlation coefficients are much lower than 0.5 in different scenarios.