一种高隔离度的缝隙型超宽带MIMO天线设计

针对超宽带传输在无线通信系统中的要求,设计一种以FR4为介质基板的高隔离度超宽带MIMO(Multiple Input Multiple Output)天线。天线类型为共面波导馈电的缝隙型,由两个正交放置的辐射单元组成,辐射贴片为拱形贴片,为了减小两个辐射单元之间的相互耦合,在接地板的对角线上增加了三条互相平行的矩形枝节。实测结果表明：该天线的工作范围为3.05～10.8 GHz,满足超宽带天线要求,并且端口隔离度S₂₁均低于-27 dB,峰值增益为4.5 dB,包络相关系数(Envelope Correlation Coefficient, ECC)均小于0.03,因此在超宽带领域具有良好的应用前景。     

双频手机天线设计

本文设计了一种具有8个单元的MIMO天线,可在2.4～2.6 GHz和3.4～3.6 GHz范围内工作,适用于5G手机通信系统。首先设计一款基于倒F天线的单元双频天线,通过在倒F天线的基础上增加枝节来实现双频工作,通过弯折枝节设计来减小其所占空间,实现小型化设计。单元天线最大增益为6.3 dB,当它工作在2.5 GHz时天线效率约为94%;当它工作在3.5 GHz时,天线效率为83%。进一步地,通过将两个单元天线对称放置于地板上形成双频双天线MIMO结构。双频双天线最大增益为6.3 dB,该天线工作在2.5 GHz时效率为92%,工作在3.5 GHz时效率为82%。由于双天线间隔距离较大,所以它们之间的耦合度较小,隔离度均大于10 dB,满足设计要求。将各个天线单元分布在地板上下两侧,每侧各两个天线并呈对称分布实现双频四单元天线设计。该天线最大增益为6.1 dB,当它工作在2.5 GHz时天线效率为93.5%,当它工作在3.5 GHz时天线效率为75%。由于各个天线之间距离较大,所以它们拥有较好的隔离度。设计双频八单元天线,将八个单元天线分别位于地板上下左右侧,通过地板刻蚀L型缝隙的方...     

Ku波段宽频带双极化微带天线阵的设计

采用十字形缝隙耦合,层叠贴片和微带线馈电的结构形式,设计了一适用于Ku波段的宽频带双极化四元微带天线阵.利用电磁仿真软件CST5.0微波工作室对天线的电特性进行仿真优化,并制作了实物模型,实测结果和仿真结果吻合良好.两馈电端口驻波小于2的阻抗带宽分别达到20.9%和46.2%,端口隔离度高于17.5dB,天线增益11dBi.     

一种手持终端的470 MHz频段IoT天线设计

许多手持终端设备都需要一种轻便、紧凑的接收和发射天线,FPC天线以重量轻、厚度薄等特点收到广大设计师的青睐。为获得适合尺寸、带宽和增益的天线,提出一种以FPC软材质为集成平台,采用传输线与天线为一体化设计,在保持天线大小不变的情况下,通过增加耦合枝的方式增强辐射单元能量耦合,从而有效改善带宽和提升增益。传输线与天线一体化设计可以有效利用天线空间,改善端口特性。通过仿真与实际测试,天线带宽满足在470 MHz～510 MHz工作频段, S_(11)<-10 dB。在490 MHz处S_(11)<-12 dB,有效增益0 dBi。     

6阵元智能天线赋形方法性能测试研究

本文研究蜂窝小区6阵元智能天线在不同场景下的天线赋形增益,及不同智能天线赋形算法的性能。实验测试结果表明,对于6阵元智能天线,采用赋形比不采用赋形方式能得到3—5dB的增益,采用特征分解赋性算法（EBB）比固定波束赋形算法（GOB）增益高1—3dB左右。     

一种用于FOD检测系统的V波段波导缝隙阵列天线

提出了一种适用于跑道异物（Foreign Object Debris, FOD）检测系统的V波段波导缝隙阵列天线。所提出的阵列天线工作频带为74～79 GHz,阵面包含2 048个单元。天线采用多模波导缝隙阵列天线形式,并设计了波导功分网络,具有高增益、低剖面等优良特点。天线整体结构厚度10 mm以内,辐射效率50%以上。天线的实测结果表明,理论结果和测试结果吻合,具有较高的工程实用性。     

面向5G高隔离度4单元MIMO手机天线设计

设计了一个4单元高隔离度手机天线,由4个辐射单元组成,辐射单元分别位于天线的4个角落。对天线辐射单元进行分析测试,测量天线辐射单元工作频段为3.43 GHz～3.86 GHz,覆盖5G移动通信测试频段。MIMO天线工作频段在端口回波损耗小于-10 dB阻抗带宽条件下,工作频段为3.45 GHz～3.64 GHz;在端口回波损耗小于-6 dB阻抗带宽条件下,天线工作频段为3.23 GHz～3.96 GHz。新设计的圆形开槽结构能减少天线和电子元器件耦合,并且天线具有良好的全向性和辐射特性。MIMO天线在3.2 GHz～4 GHz频率内,天线辐射效率为65%～73.4%。仿真表明,脑部辐射SAR(Specific Absorption Rate)参数小于1.6 W/kg,天线对人体影响较低。     

基于拉普拉斯分布天线阵列下MIMO性能研究

多天线系统是可以克服多径干扰的影响并增加频谱使用效率的系统.MIMO系统的容量增加主要取决于无线电信道的空间相关性性能.主要研究了MIMO天线阵列系统的性能,包括MIMO空间时间相关性和天线阵列配置,推导了当角能量遵循拉普拉斯分布时均匀线性阵列、均匀圆阵的衰落相关性解析公式,并分析了两种天线阵列下的系统信道容量.通过计算机程序模拟仿真验证了分析结果,验证结果表明当阵元间距增大或者衰减因子减小(角度扩展增大)时,空间衰落相关性减小,系统信道容量增大,提升了系统性能.     

一种应用于5G物联网的八端口高隔离二元宽带MIMO天线

文中提出了一种应用于5G物联网的八端口高隔离二元宽带MIMO天线,天线整体结构包括两块正交放置的介质基板以及系统地板,在每块介质基板正面放有2个对角设置的二元双馈天线对;每个天线对有2个馈电板和1块短路板,两馈电板靠近介质基板边沿,分别固定在辐射片的长边与短边下方,使其交叉以利用极化分集;空间分集通过将2个天线对角线定位在天线结构的相对两侧实现;为减少相互耦合,在每个单元顶板下的接地面一侧刻蚀有矩形槽,以减小同一天线单元2个端口之间的电流流动。此外,处于不同平面的天线单元采用正交布局达到空间分集,增强MIMO天线系统隔离度。在工作频段内,天线端口间实现的最大隔离小于-11.12 dB,天线效率为65.3%～84.5%,天线单元间的包络相关系数(ECC)低于0.09。该天线8个端口所覆盖的最小频率范围为2 100～3 700 MHz和4 100～5 800 MHz,可以支持国内外大部分商用5G-IoT频带,作为MIMO天线用于物联网和5G应用领域。     

一种宽频带四单元微带天线阵设计*

综合运用了H型缝隙耦合馈电技术和引入空气层技术展宽了天线的频带,设计出一个工作在Ku波段的宽频带微带天线单元并组成四单元阵列。该天线由两层介质板构成,并利用180°反相馈电抑制了高次模的耦合激励,降低了交叉极化电平。使用三维电磁场仿真软件(Ansoft HFSS)对微带天线进行仿真优化,仿真结果表明,天线单元性能良好,相对阻抗带宽(S11≤-10 dB)为8.5%,增益为8.05 dB。四单元天线阵列相对阻抗带宽(S11≤-10 dB)达到16.6%,增益为13.7 dB。天线阵列性能良好,设计方法具有很好的可扩展性。归纳总结出的介电常数计算式也具有普遍性。     

Millimeter‐wave planar high gain SIW antenna using half elliptic radiation slots

This article reports a high gain millimeter‐wave substrate integrated waveguide (SIW) antenna using low cost printed circuit board technology. The half elliptic slots which can provide small shunt admittance, low cross polarization level and low mutual coupling are etched on the board surface of SIW as radiation slots for large array application. Design procedure for analyzing the characteristics of proposed radiation slot, the beam‐forming structure and the array antenna are presented. As examples, an 8 × 8 and a 32 × 32 SIW slot array antennas are designed and verified by experiments. Good agreements between simulation and measured results are achieved, which shows the 8 × 8 SIW slot array antenna has a gain of 20.8 dBi at 42.5 GHz, the maximum sidelobe level of 42.5 GHz E‐plane and H‐plane radiation patterns are 22.3 dB and 22.1 dB, respectively. The 32 × 32 SIW slot array antenna has a maximum measured gain of 30.05 dBi at 42.5 GHz. At 42.3 GHz, the measured antenna has a gain of 29.6 dBi and a maximum sidelobe level of 19.89 dB and 15.0 dB for the E‐plane and H‐plane radiation patterns. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:709–718, 2015.     

Dual‐band CPW fed MIMO antenna with polarization diversity and improved gain

A dual‐band MIMO slot antenna with polarization diversity and improved gain is proposed in this article. The antenna is composed of two C‐type back‐to‐back connected slot resonators and offers resonances at 3.5 and 5.2 GHz. This antenna element is further used to design a MIMO antenna. By introducing one U‐shaped slot between two antenna elements, isolation between the ports of this MIMO antenna is improved further. Finally, an artificial magnetic conductor (AMC) is placed below the MIMO antenna to enhance its gain. Gain enhancement of 1.5 and 2.2 dB is achieved at lower and upper band, respectively. S‐parameters, radiation patterns, gain, envelope correlation coefficient, and channel capacity loss are investigated to conclude about its performances in MIMO applications. Dual band dual polarization (circular and linear), improved isolation, polarization diversity (right‐hand circular polarization and left‐hand circular polarization), gain enhancement all are presented in a simple design represents the novelty of the proposed MIMO antenna.     

Circularly polarized stacked patch antenna array with enhanced bandwidth for S‐band applications

In this article, a circularly polarized coupled slot 1 × 4 stacked patch antenna array with enhanced bandwidth is proposed for S‐band applications. Initially, a patch antenna radiating at 2.79 GHz is designed and maximum energy from feedline to patch element is coupled using two rectangular slots. Whereas, a parallel feedline structure is designed to provide polarization flexibility by creating 0, 90 , and 180^o phase differences. Then, a truncated patch element is vertically stacked in the design to achieve broader bandwidth of 600 MHz over frequency range from 2.4 to 3.0 GHz. Finally, a coupled slot 1 × 4 array stacked antenna array having feedline line structure to provide 90^o phase difference for circular polarization is designed and fabricated for measurements. It is observed that the final design achieved target specification having impedance matching (|S₁₁ | (dB) < ?10 dB over 2.4 to 3.0 GHz, broad band circular polarization, and 11.5 dBic total gain. Overall, a good agreement between simulated and measurement results is observed.     

Highly‐isolated unidirectional multi‐slot‐antenna systems for enhanced MIMO performance

In this article, an improved approach is presented for designing Electromagnetic Bandgap (EBG) reflectors for slot antennas by using a waveguide aperture source in simulating reflection phase test. In this manner the nonplanar nature of the near field at the location of the source, that is, antenna, as well as its loading effect on the reflector are incorporated in the design of a mushroom‐type EBG structure operating at 5.3 GHz. This EBG design performs as an efficient reflector in normal wave incidence while suppressing the substrate‐bound modes propagating in the azimuthal directions. The designed EBG reflector is employed in several two‐slot‐antenna structures to establish excellent antenna isolation of at least 25 dB and single antenna gain of 5 dB at 5.3 GHz in each scenario. To further reduce coupling, the antennas are reoriented to benefit from polarization mismatch and radiation pattern nulls, resulting in isolation values of above 40 dB for antennas spaced one wavelength apart. The two‐antenna structures are also characterized for MIMO performance in a reverberation chamber and demonstrate an impressive diversity gain of better than 8 dB in a rich multipath environment. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:289–297, 2014.     

Beam scanning annular slot‐ring antenna array with via‐fence for wireless power transfer

Wireless power transfer has been the field of research for many decades, and with technological advancement and increase in wireless mobile devices, the future of wireless power transfer technology is very promising. The major requirement of wireless power transfer is an efficient and compact antenna array with high gain and flawless scanning performance. In this article, a 4 × 8 element array is proposed with a gain of 18 dB and scanning capability of ±45^° in azimuth and elevation plane at 5.8 GHz. The overall size of the array is 100 mm × 200 mm. The element separation in the array is only 0.48 λ. There was strong mutual coupling due to smaller separation, which has been minimized with the application of via‐fence around the antenna element. A dual feed circularly polarized annular slot‐ring antenna is proposed and analyzed with via‐fence to develop an array of 4 × 8 elements. The antenna array reflection coefficient obtained is less than 20 dB for different scan angles and the gain of the array obtained is also within 2 dB for ±45^° scan angles.     

A nonuniform array of slots in the broad‐walls of rectangular waveguides partially filled with dielectric slabs

This article describes a new nonuniform slot antenna array in the broad wall of rectangular waveguides partially filled with a dielectric slab. The slot elements are nonuniformly spaced to achieve a higher side lobe level while the amplitude and phase of their excitations are identical. Each slot element is fed by one dielectric‐loaded rectangular waveguide with one end shorted for structural simplicity. Experimental results for an 8‐element linear slot array operating at X‐band show that the side lobe level is 15 dB over a frequency range from 9.5 GHz to 10.5 GHz. The simulated side lobe level can reach 20 dB for a 16‐element linear array. Experimental results show that the side lobe level of a slot array can be improved using nonuniform element spacing without degrading the broadside radiation and gain. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

A dual‐polarized low‐profile microstrip patch antenna with U‐ or M‐shaped feed network

In this article, a dual‐polarized low‐profile microstrip patch antenna with U‐ or M‐shaped feed network is presented. The U‐ or M‐shaped feed network is printed on the same layer, which can achieve dual bands (5.3 and 5.8 GHz) and low profile (0.06 λ_g). Dual polarizations and high isolation are realized by making use of a quasi‐cross‐shaped slot feeding. Moreover, the port isolation is better than 25 dB, and the antenna gain is above 8.4 dBi for the two ports. And the cross‐polarization levels in both E and H planes are better than ‐30 dB for the two polarization ports, respectively. The design is suitable for array application in MIMO system. Details of the proposed design and experimental results are presented and well agreed.     

A WiMAX circularly polarized antenna array using slot‐coupling feeding technique

In this letter, we present a circular polarization antenna array using the novel slot‐coupling feeding technique. This antenna includes eight elements which are installed in line, each array element is fed by means of two microstrip lines with equal amplitude and phase rotation of 90°. The feeding microstrip lines are coupled to a square patch through a square‐ring slot realized in the feeding network ground plane. With the presence of the slots, this antenna array is able to cover the range of frequency of 3 GHz to 4 GHz. The size of the proposed antenna array is 7λ × 1.8λ × 0.4λ. The measured gain is 15.2 dBi and the bandwidth of S11< ?10 dB is 1 GHz (3–4 GHz, 28%). The antenna array is suited for the WiMAX applications. With the use of slot‐coupling feeding technique, the measured bandwidth for axial ratio < 3 dB is about 24% in the WiMAX frequency band (3.3–3.8GHz). The measured HPBW of the y–z planes is larger than 62°. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:567–574, 2016.     

Gain and isolation enhancement of patch antenna using L‐slotted mushroom electromagnetic bandgap

In this paper, the application of the L‐slotted mushroom electromagnetic bandgap (LMEBG) structure to patch antenna and antenna array is investigated. A coaxial fed patch antenna and antenna array are designed at 5.8 GHz, center frequency for ISM band (5.725‐5.875 GHz). Two layers of LMEBG are placed around the patch to achieve a gain enhancement of 1.9 dB. Measured results show a bandwidth enhancement of 300 MHz with an additional resonant frequency at 5.6 GHz with 4.5 dB of gain. A 5 × 2 array of LMEBG is used to achieve a 2 dB mutual coupling reduction and 2 dB gain enhancement for a two‐element H‐coupled patch antenna array.     

A compact dual‐band 2 × 1 metamaterial inspired mimo antenna system with high port isolation for LTE and WiMax applications

This article proposes a compact (43 × 26 × 0.8 mm³) dual‐band two‐element metamaterial‐inspired MIMO antenna system with high port isolation for LTE and WiMAX applications. In this structure, each antenna element consists of a square–ring slot radiator encircling a complementary split ring resonator. A tapered impedance transformer line feeds these radiating apertures and shows good impedance matching. A 2 × 3 array of two‐turn Complementary Spiral Resonator structure between the two antenna elements provides high dual‐band isolation between them. The fabricated prototype system shows two bands 2.34 – 2.47 GHz (suitable for LTE 2300) and 3.35 – 3.64 GHz (suitable for WiMAX). For spacing between two antennas of 10 mm only, the measured isolation between the two antenna elements in the lower band is around ?32 dB while that in the upper band is nearly 18 dB. The system shows a doughnut‐shaped radiation patterns. The peak measured antenna gains for the proposed MIMO system in the lower and higher bands are 3.9 and 4.2 dBi, respectively. The MIMO system figure of merits such as the envelope correlation coefficient, total efficiency are also calculated and shown to provide good diversity performance.