Electromagnetic coupling reduction in dual-band microstrip antenna array using ultra-compact single-negative electric metamaterials for MIMO application

In this paper, an ultra-compact single negative(SNG) electric waveguided metamaterial(WG-MTM) is first investigated and used to reduce the mutual coupling in E & H planes of a dual-band microstrip antenna array. The proposed SNG electric WG-MTM unit cell is designed by etching two different symmetrical spiral lines on the ground, and has two stopbands operating at 1.86 GHz and 2.40 GHz. The circuit size is very compact, which is only λ_0/33.6 ×λ_0/15.1(where λ_0 is the wavelength at 1.86 GHz in free space). Taking advantage of the dual-stopband property of the proposed SNG electric WG-MTM, a dual-band microstrip antenna array operating at 1.86 GHz and 2.40 GHz with very low mutual coupling is designed by embedding a cross shaped array of the proposed SNG electric WG-MTM. The measured and simulated results of the designed dual-band antenna array are in good agreement with each other, indicating that the mutual coupling of the fabricated dual-band antenna array realizes 9.8/11.1 d B reductions in the H plane, 8.5/7.9 d B reductions in the E plane at1.86 GHz and 2.40 GHz, respectively. Besides, the distance of the antenna elements in the array is only 0.35 λ_0(where λ_0 is the wavelength at 1.86 GHz in free space). The proposed strategy is used for the first time to reduce the mutual coupling in E & H planes of the dual-band microstrip antenna array by using ultra-compact SNG electric WG-MTM.

Resonant Length Formulations for Dual Band Slot Cut Equilateral Triangular Microstrip Antennas

The dual band equilateral triangular microstrip antennas are realized by cutting the slots of either quarter wave or half wave in length, inside the patch. In this design, however these simpler approximations of slot length against the frequency do not give closer results for different slot lengths and there positions inside the patch. In this paper, the modal variations of slot cut patch antennas over wide frequency range are studied. It is observed that the slot does not introduce any mode but reduces the higher order mode resonance frequency of the patch and along with the fundamental mode realizes dual band response. The formulations of the resonant length for the mode introduce by the slots in these antennas are proposed. The resonance frequencies calculated using proposed formulations agree well with the simulated results with an error of less than 5%.

RECONFIGURABLE DUAL-BAND CIRCULARLY POLARIZED MICROSTRIP PATCH ANTENNA FOR WIRELESS APPLICATIONS

A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.

Aperture Coupled Microstrip Antenna for Dual-Band

This paper presents air gap aperture coupled microstrip antenna for dual-band operation over the frequency range of (2.9 to 6.0 GHz). This antenna differs from any other microstrip antenna with their feeding structure of the radiating patch element. Input signal couples to the radiating patch trough the aperture that exists on the ground plane of microstrip feed line. The dual-band achieved by variation of air gap [2 mm to 6 mm] between single patch antenna and aper-ture coupled microstrip antenna. The main advantage of this type antenna is increased the bandwidth of the antenna as compared to a single layered patch antenna. The two resonant frequencies can vary over a wide frequency range and the input impedance is easily matched for both frequencies. The obtain ratios of resonance frequencies are variable from 2.1 GHz to 1.1 GHz with increasing the air gap between single patch and aperture coupled microstrip antenna. The measured return loss [–14 dB] exhibits an impedance bandwidth of 35%. The input impedance and VSWR return loss have been measured with the help of Network analyzer.

Experimental Study of Stacked Rectangular Microstrip Antenna for Dual-Band

A dual-band characteristic of stacked rectangular microstrip antenna is experimentally studied. It is a probe fed antenna for impedance matching with 50Ω coaxial cable. This antenna works well in the frequency range (2.86 to 4.63 GHz). It is basically a low cost, light weight medium gain antenna, which is used for mobile communication. The variations of the length and width (1mm) of the stacked rectangular patch antenna have been done. And it is found dual resonance with increasing lower resonance frequency and almost constant upper resonance frequency with increases of the length & width of rectangular microstrip antenna. The input impedance and VSWR, return loss have been measured with the help of Network analyzer.

Analysis of Rectangular Notch Antenna for Dual-Band Operation

In this paper a design of single layer rectangular notch microstrip antenna for dual-band is proposed and experimentally investigated. This antenna is excited by microstrip line. Direct microstrip coupling with proper matching transformer has been used. Design is made for optimized notch dimension for two resonant frequencies. These resonance frequencies change with the variation in length and width of the notch. The input impedance and VSWR have been measured with the help of Network analyzer. It is found that the input impedance and VSWR depends variation in length and width of the notch microstrip antenna.

加载寄生单元的双频宽带天线设计与研究

为展宽微带天线的带宽,设计一种加载寄生单元的双频微带天线,适用于3.5 GHz和5.8 GHz的WLAN/WIMAX通信和RFID技术的应用。所设计天线通过在主辐射贴片开T形槽、在接地板条带处开矩形槽和加载寄生单元的方式来实现双频段和扩展整体工作带宽,同时也提高了天线设计的灵活性。在馈电上采用偏心嵌套馈电,可以方便调节天线的阻抗匹配特性。该天线工作频段分别为3.40~3.70 GHz和5.49~6.18 GHz,相对带宽分别为8.57%和11.90%,且仿真和实测结果较为吻合,与传统天线相比,具有双频宽带的优势。

加载对称谐振臂的双频段5G微带天线

为满足工信部最新分配的5G频段要求,设计了一种加载对称谐振臂的新型微带天线。天线辐射单元主要由2个内外嵌套的圆环形贴片和附着在外侧圆环两侧的对称谐振臂贴片组成。内侧和外侧圆环尺寸分别决定天线高频与低频的谐振点位置,对称谐振臂则用于优化双频段的辐射性能。利用电磁仿真软件HFSS对天线结构进行设计与优化,并借助矢量网络分析仪对天线实物进行测试。结果表明:所设计天线具有3.27~3.80 GHz和4.80~5.08 GHz的带宽,对应的最大增益分别达到了3.27 dBi和2.34 dBi,在工作频段内满足S11小于-10 dB,电压驻波比(VSWR)小于2。所设计的天线结构简单、小巧便携、易于集成,有较好的全向辐射特性和较大的增益。

C/X双频双圆极化共口径微带天线设计

设计实现了一款C/X双频双圆极化共口径微带天线,在C/X频段均能以双圆极化方式工作,有效提高了天线的口径利用率。采用寄生结构和L型探针耦合馈电拓展了天线的阻抗带宽;以嵌套方式将X波段天线置于C波段天线的间隙处实现了共口径设计;通过对称反相馈电技术实现了良好的交叉极化比。测试结果表明,C波段的阻抗带宽和3 dB轴比带宽分别大于23%和17%;X波段的阻抗带宽和3 dB轴比带宽分别大于28%和18%;测试频点处的交叉极化比均大于25 dB。

基于加载寄生带的双频天线设计

文中提出了一种双频印刷天线设计方法,覆盖2.4 GHz和5.2 GHz频段。该天线通过在偶极子天线振臂旁平行放置寄生单元,降低天线在高频段的输入阻抗(通常输入阻抗远大于50Ω),从而实现良好的阻抗匹配,在主谐振频段外产生新的寄生谐振频点,达到双频段工作的目的。为了验证所提出的天线设计方案,建立了仿真模型,并加工了天线实物。通过仿真分析和实测发现,改变寄生金属单元的位置和尺寸只影响高频段谐振频点,几乎不影响低频段谐振频点,而偶极子天线尺寸的改变只影响低频段谐振频点,不影响高频段谐振频点。文中设计的天线具有双频段相互独立特性,因此天线的两个谐振频段可根据需求独立设计。

一种双频四模极化可重构天线

极化可重构天线是一种极化状态可切换的新型天线,它具有减少系统中天线数量、利于频率复用等优点.本文基于模式可切换馈电网络,提出了一种具备两个工作频带(1 GHz和2.1 GHz)和四种极化状态(0°和90°线极化和左、右旋圆极化)的直流偏置电压数量较少的双宽带极化可重构微带天线.双频比可实现范围为1.7~3.5.本文详细介绍了双频可切换馈网和天线的设计过程.本文在分支线耦合器的基础上加载4个开路枝节和12个二极管,通过切换二极管状态使馈网输出信号幅度和相位可以在四种模式之间切换,从而满足四种极化状态的激励条件;并且基于参数分析,提出了调节双频比和提高轴比带宽的方法.天线方面,本文在双层L探针贴片天线的基础上设计了一种准同轴去耦结构和一种T形结匹配结构.仿真结果表明天线具有良好的双频双极化性能.最后,对馈电网络和天线的整体进行了仿真和加工实测.实测结果表明,该天线在0.94~1.07 GHz(13%)和1.99~2.27 GHz(12.6%)两个较宽的频带内仅用2个直流偏置电压(不包括地板电位)就实现了四种极化状态的切换,低、高频带内线极化状态的法向增益分别为7.6 dBi和7.3 dBi,圆极化的法向增益分别为6.3 dBic和5.9 dBic.本文设计的双频四极化可重构天线为RFID系统、WLAN系统和卫星导航系统提供了新的解决方案.

一种双频超薄吸波结构在微带天线中的应用

设计了一种新型超薄双频带雷达吸波结构,通过提取阻抗参数、分析表面电场和电流分布,阐明了其吸波原理,并将其用于双频带微带天线,减缩天线带内雷达散射截面.结果表明,该结构在两个不同的频段内实现了高效吸波,且吸波效果具有入射角稳定性和极化角不敏感性;加载该吸波结构后,微带天线的辐射性能保持不变,而在天线的工作频率4.29GHz和6.49GHz处,其雷达散射截面分别减缩了8.59dB和9.9dB.实测与仿真结果相吻合,表明该结构能够有效应用于双频带天线的带内隐身.

适合临近空间通信的Ka/V双频口径耦合天线设计

为了减缓飞行器在临近空间高速飞行时产生的等离子体鞘套"黑障"对其通信影响,根据ITU分配的临近空间3区业务频段,设计了一种在Ka/V双频段工作的口径耦合微带天线。该天线在中间缝隙开一圆孔,通过改变圆孔大小实现双频工作,并组成1×4的天线阵列,实现了在Ka和V两个频段的通信。设计结果表明:在Ka频段的-10 d B带宽达到11.33%,V频段带宽达到2.52%,满足其在临近空间3区业务的通信频段。该天线易于实现,结构简单,可为临近空间通信飞行器天线设计提供参考。

一种双频微带天线的分析与设计

对平行双缝微带天线进行了理论分析,设计了一种平行双缝的双频微带天线,并利用仿真软件HFSS 10.0对天线的特性进行了仿真验证。结果表明,在天线驻波比VSWR≤2.0时,该天线工作的频段分别为1.77～2.17 GHz和2.71～2.94 GHz,且天线的相对带宽分别达到20.31%和8.12%,天线的整体辐射性能良好,且结构简单易于实现。所设计的天线可以作为双频宽带天线。

一种层叠结构双频圆极化GPS天线的设计

运用腔模理论,结合多馈点网络和表面开槽技术,提出了一种新型、高效的层叠结构的GPS微带天线.时域有限差分法(FDTD)模拟仿真表明,该设计通过改变贴片以及其上所附加调节枝节的尺寸,使电场强度重新分布,可实现在所需工作频率点的谐振.同时,上层寄生单元上开孔,在提高天线辐射场的对称性的同时,有效地提高了天线的辐射效率.在通信波长范围,该设计结构尺寸小、频带宽、易于实现双频圆极化,在无线通信领域具有重要的发展前景.

小型化双频段GPS微带天线

为了满足GPS定位准确性和可靠性的需要,要求天线在GPS两个频率上实现圆极化.该文介绍一种通过单个探针馈电的双层正方形切角的微带贴片天线.此天线采用不同介电常数的微波陶瓷基片,与常规的双频圆极化天线相比,其尺寸减小了且没有在两层贴片间引入空气层,结构紧凑,便于加工.文中给出了天线的详细设计及实验结果,并进行了讨论.实测结果证明了该设计的有效性.

毫米波微带双频平面天线阵研究

设计了一种新型毫米波微带双频平面天线阵,该天线阵单元采用凹槽加载中心馈电结构。这种馈电方式恰好等效为在微带贴片上加载了一个电抗,通过调节馈电线的长度,可以获得两个零点,从而使微带天线实现双频工作。基于这种馈电结构和并联馈电网络,制作了平面4×4双频段天线阵。根据实验和仿真结果的比较,二者拟合较好。实测的双频天线阵工作在32.5 GHz和35.7 GHz,天线阵的增益16.25 dB,辐射效率为82%。

一种用于WLAN的U形槽加载的双频贴片微带天线

提出了一种在贴片上加载改进的U形缝隙的新型双频微带天线.该天线结构简单,可以应用在无线局域网802.11b(2.4-2.48GHz)和802.11a(5.150-5.350GHz)的系统中,而且只需简单修改天线尺寸参数,就可以实现对天线高频段和低频段的调节.本天线使用Ansoft公司的HFSS软件进行仿真和优化,在低频和高频分别获得100MHz和300MHz的带宽,并且能达到实际应用的波束宽度、增益和交叉极化电平.

一种新型低剖面、双频、双极化宽频带阵列天线的研究与设计

设计了一种结构新颖的双频、双极化基站阵列天线并进行了仿真和实验研究。双频阵列由采用新型印刷金属圆弧耦合馈电的圆环天线（低频）与交叉微带印刷振子（高频）嵌套构成。首次采用印刷金属圆弧耦合馈电拓宽了圆环天线带宽，并利用反相馈电技术提高了端口隔离度（〈-28aB）、加强了方位面方向图的对称性、降低了交叉极化电平；对在双频结构中受影响较大的高频阵元进行了相位误差分析；最后给出了整个双频阵列的实测结果，与仿真理论值吻合较好。该阵列天线具有宽频带（806～960MHz、1710～2170MHz）、低剖面（35nun）、高极化隔离、结构紧凑、方位面波瓣恒定（65±6°）等优点。适合用于双频基站系统或星载／舰载通信系统。