Ku波段多频高增益天线研究

针对传统平板天线频带单一,增益不高,方向性差等缺点,本文将电磁波的增强透射特性研究应用到天线的设计中,结合类f-p腔原理,设计了一款具有双频带、高增益的波导缝隙天线。天线在中心频率10.9 GHz和13.7 GHz的增益分别达到了10.8 dB和11.4 dB,并且相对于传统单缝波导天线,天线在中心频率点处E面的半波功率波束宽度分别减小了114°和90°。仿真结果和实测结果吻合度较高,尤其频带处于在Ku波段,在卫星雷达领域具有很大的应用价值。     

C波段超材料基板高增益微带天线

针对普通微带天线增益较低的缺点,在普通微带天线上引入带有双面树枝状结构的新型负磁导率材料作为天线的基板,设计了中心工作频率为5.28 GHz的微带天线,对此天线的性能进行了研究.结果表明,通过引入负磁导率材料,天线的性能有了显著的改善,侧向辐射减弱,前向辐射增强,相对于普通微带天线,负磁导率材料微带天线的增益最大提高了2.47 dB,E面方向图的半功率波束宽度收缩了21.93°.     

基于各向异性混合介质近零折射率超材料的高增益微带天线

根据斯涅尔定律,透过近零折射率超材料(Near Zero Index Metamaterials,NZIM)的电磁波会变为垂直于超材料表面的高指向性波束。这种特性使NZIM材料被广泛应用于高增益及高定向性天线设计中。基于此,设计一款基于各向异性混合介质近零折射率超材料的高增益微带天线。混合介质超材料单元由F₄BM介质及高纯度铜导体组成。根据金属等离子体理论,金属阵列等离子体频率与入射波谐振频率相近时,会呈现近零介电常数。通过合理调节金属半径及介质单元周期,最终使该混合介质在9.5～10.2 GHz频段内折射率近零且等效阻抗接近1,能够与空气匹配。对基于混合介质超材料的微带天线进行加工测试,结果表明,加载混合介质覆层后,微带天线增益明显提高,最大增益提高4.1 dB。     

S波段新型负磁导率微带天线

将树枝状结构负磁导率材料作为微带天线的基板,模拟和实验研究了负磁导率材料对S波段微带天线的影响.实验结果表明,由于负磁导率材料的引入,微带天线的性能得到了明显改善,微带天线的侧向辐射减弱,前向辐射增强,定向性和增益提高,相对带宽增大.经过优化设计负磁导率S波段微带天线的增益相比普通微带天线提高了1.73 dB,相当于有效辐射功率提高了49%;E面半功率波束宽度收缩了17°.     

一种新型的双频高增益天线设计

为了适应现代双频通信系统的要求,该文将褶皱结构的透波增强特性应用于天线设计中,并在中心圆孔处添加环形金属柱,设计了一个双频高增益天线。仿真和测试结果表明,在12.7 GHz和14.4 GHz处,天线的增益分别为12.0 dB和12.9 dB,相对于传统天线分别提高了5.6 dB和6.3 dB。此外,天线的半功率波束宽度(Half Power Beam Width, HPBW)也得到了较好的优化。     

高温超导圆极化微带天线辐射性能的研究

本文设计并研制了2GHz敷铜板圆极化微带天线及4.5GHz高温超导(HTS)圆极化微带天线.2GHz敷铜板圆极化微带天线的半功率角为63°,最好轴比为1.2dB;4.5GHz的HTS圆极化微带天线相对于银天线有3dB的增益改善,其半功率角大于63°.     

LTE专网1.4G及1.8G高增益天线的仿真与设计

本文设计了两款LTE专网1.4G及1.8G高增益天线。仿真结果表明：前向天线的设计在保证E面110度H面71度半功率波束宽度的情况下,在1.4G和1.8G上的增益可达7.8dB,定向天线在E面100/120度H面可达40度半功率波束宽度的情况下,在1.4G和1.8G上的增益可达10dB/9.8dB。该天线的设计可用于对增益要求较高的1447-1467MHz频段和1785-1805MHz频段的LTE专网系统。     

一种宽带宽波束圆极化微带天线的设计

文设计了一款宽带宽波束圆极化微带天线。 天线采用堆叠的双层圆贴片结构,结合四点顺序旋转馈电方式,实现了宽带圆极化辐射性能;在叠层圆贴片周边加载垂直接地金属柱环形阵,利用波束引向作用和等效零模谐振特性,在大带宽范围内实现了半功率波束宽度(HPBW)的有效展宽,并保证宽带宽波束内的圆极化辐射性能。 对天线进行了加工、测试。 实测结果表明,S11 小于-10 dB 的阻抗带宽( 4. 54 GHz ~ 11. 50 GHz)为 87%,覆盖了期望的应用工作频带6 GHz ~ 10 GHz;轴比小于3 dB 的带宽达到了33. 1%(6. 71 GHz~ 9. 36 GHz);HPBW 在6 GHz~ 8 GHz 范围内接近100°,在整个带宽内均超过 75°;除了 9. 5 GHz 以上频段,工作频带内的 6 dB 轴比波束宽度覆盖范围都接近 200°,表明天线在宽带和宽波束内具有良好的圆极化性能。     

Peano分形加载单极子辐射性能的研究

对有限地板尺寸和介质填充情况下Peano分形加载单极子天线的辐射特性进行了研究.利用HFSS分析了地板尺寸和填充介质材料对天线反射系数、辐射方向图和增益的影响.仿真表明:随着地板尺寸的减小,天线的阻抗带宽和增益明显减小,H面方向图变化不大,而E面方向图的半功率波束宽度增大,波束仰角减小;填充材料的介电常数过大会导致天线性能的恶化.在分析研究的基础上,设计并研制了地板尺寸为220mm×220mm的一阶和二阶Peano分形加载单极子天线.天线分别实现了45°和36°的波束仰角,50°和45°的半功率波束宽度.仿真与实测结果均表明凋节地板尺寸是控制Peano分形加载单极子天线E面半功率波束宽度和波束仰角的一种简单而有效的方法.     

加载人工电磁结构的高增益耐高温天线设计北大核心CSCD

本文设计了一款加载人工电磁结构的耐高温天线，为实现弹载天线共形后增益的提高，采用微带天线加载近零折射率材料层方式实现增益提高。通过在天线外部覆盖天线罩形式实现隔热功能，可实现在罩的上表面持续350℃加热时，实现120s内馈电端口处温度小于100℃。首先设计了一款工作在35GHz处的微带天线，实现最大增益为8dBi，其次通过加载两层近零折射率材料和加天线罩所需地板对电磁波的反射，实现天线增益提高到15.4dBi，远高于单个微带天线增益。后期进行了加工与实测，常温实测结果天线最大增益达到14.5dBi左右，E面和H面波束宽度约在24°左右，实测结果与仿真结果差别不大，不仅实现了对单个微带天线增益的较大提升；而且高温隔热性能满足要求。     

宽带低交叉极化超材料漏波天线的设计

基于基片集成波导结构提出了一种新型双层电磁超材料单元，并验证了其左手特性。将超材料单元应用于漏波天线的设计，所设计的天线由15个双层电磁超材料单元组成。将设计好的天线进行加工测试，测试与仿真结果吻合较好，表明漏波天线的工作频带为7.20~12.70GHz，在工作频带内可实现从后向-78°到前向+80°的连续主波束扫描，天线在工作频带内的测试增益均大于10dBi，峰值增益为15.2dBi，3dB增益带宽达到50.2%。此外，该漏波天线具有很低的交叉极化电平，交叉极化始终比主极化低至少30dB。相比于新近文献报道的同类型超材料漏波天线，所设计的天线具有更加优越的电气性能。     

A miniaturized metamaterial slot antenna for wireless applications

A novel miniaturized five band metamaterial inspired slot antenna is reported. The proposed design consists of a ring monopole and metamaterial Rectangular Complementary Split Ring Resonator (RCSRR) as the radiating part, two L and one T–shaped slot as the ground plane, respectively. Miniaturization in the proposed design is accomplished by metamaterial RCSRR, and also, it helps the antenna to operate at 2.9 and 5.2 GHz frequency bands. The aforementioned miniaturization process leads to about 46.8% reduction in volume of the proposed design, as compared to the conventional antenna. The pass band characteristics of the metamaterial RCSRR through waveguide medium are discussed in detail. In order to enhance the operating abilities of the miniaturized antenna, slots are etched out in the ground plane, thereby making the miniaturized antenna further operate at 2.4, 5.6 and 8.8 GHz, respectively. The proposed design has an active patch area of only , with dB bandwidth of about 4.16% (2.35–2.45 GHz), 5.71% (2.63–2.76 GHz), 10.25% (4.44–4.92 GHz), 6.25% (5.42–5.77 GHz) and 2.39% (8.68–8.89 GHz) in simulation, and about 6.86% (2.25–2.41 GHz), 5.01% (2.55–2.7 GHz), 9.16% (4.58–5.02 GHz), 5.38% (5.79–6.11 GHz) and 5.42% (8.44–8.91 GHz) in measurement. The antenna has good impedance matching, acceptable gain and stable radiation characteristics across the operational bandwidths.     

大功率微波下超材料的设计和应用

为使超材料结构在大功率微波下更稳定地工作,本文介绍的超材料结构由双层打孔金属板构成,不同于常见的由介质基板构成的超材料结构.通过采用散射参数反演方法计算发现,超材料结构具有零折射率系数的特性,并对电场场强分布产生一定的影响.为了解该超材料对天线性能的影响,在实验过程中,采用松下2M244-M1型磁控管作为微波源来产生大功率微波,测试结果显示,半功率宽度由28°减小为15°,增益提高了1.7 dB.     

一种高增益Vivaldi超宽带天线

传统的Vivaldi天线具有超宽带优点,但存在定向性较差,且在工作频带的两端增益下降严重的问题。文中提出了一种高增益的Vivaldi天线,通过对传统微带线馈电结构的Vivaldi超宽带天线加载零折射率超常介质和轴向边缘梳状结构的矩形槽缝结构,提高了天线在整个工作频段内的增益。对所提出的天线进行了设计、优化和仿真分析,并制作天线样品,仿真和测试结果吻合良好。测试与仿真结果表明,在4~11 GHz的工作频段内,天线的回波损耗优于-10 dB;与传统Vivaldi天线相比,在整个工作频段内天线增益均有所提高,其中在工作频率的低端(4~6 GHz)天线增益提高2.5 dB,高端(9~11 GHz)增益提高1.5 dB。     

Metamaterial Superstrate and Electromagnetic Band-Gap Substrate for High Directive Antenna

A high directive planar antenna made from a metamaterial superstrate and an electromagnetic band-gap (EBG) substrate has been investigated. A patch antenna surrounded with EBG structures is used as the radiation source. The CST Microwave Studio is used for the simulation. The results show that the gain of the antenna with metamaterial is 21.6 dB at the operating frequency of 14.6 GHz. Compared with the patch feed with the same aperture size but without the metamaterial superstrate, the performance of the antenna is improved obviously and the gain increases about 12.4 dB.     

基于透波增强特性的高增益天线设计

为满足通信系统在天线增益方面的需求,通过将透波增强特性应用于天线设计中,提出了一种新型高增益天线。运用高频仿真软件Ansoft HFSS对天线进行了优化仿真,并加工出实物进行测试。测试结果显示,天线增益为12.9 dB,相对于传统的平板天线提高了6 dB。此外,由于设计的结构引入了环形孔结构和褶皱结构,天线的波瓣宽度测量结果为30°,相较于传统天线也减小了102°,天线的性能得到大幅提高。     

Dual Band Dual Polarization Directive Patch Antenna Using Rectangular Metallic Grids Metamaterial

In this letter, a kind of metamaterial superstrate based on rectangular metallic grids is presented to enhance the directivity of patch antenna at two frequency bands for two orthogonal polarizations. According to the periodic boundary condition, the influences of its important geometry parameters are investigated in detail by simulating its unit cell. It is found that the transmission peak frequency is intimately related to the size of rectangular metallic grid. Then, a dual band dual polarization patch antenna with metamaterial is studied and compared with conventional patch antenna. It is demonstrated that by introducing the proposed metamaterial superstrate, the gain of the patch antenna is improved by 9.5 dB at 14.1 GHz for x polarization and 12 dB at 15.4 GHz for y polarization, respectively.     

Dual band microstrip patch antenna array loaded with split ring resonators and via holes

Reduction in antenna size by using multi-band radiators play a vital role in the miniaturization of present world wireless handheld devices, as dual band behaviour of the antennas result in the integration of more than one communication standard in a single system and thus, saving the installation space required for separate antennas. In this context, this communication presents a shorted-pin dual band metamaterial inspired microstrip patch antenna array. Under the unloaded conditions, the traditional patch antenna array resonates at 5.8 GHz with gain of 9.8 dBi and bandwidth of 540 MHz. However, when each patch of this traditional antenna array is loaded with split ring resonator (SRR) and a metallic via hole is introduced in the patch, the same antenna array produces an additional resonant frequency in IEEE 802.11b/g/n 2.45 GHz Wi-Fi band with bandwidth and gain of 290 MHz and 5.6 dBi, respectively, while the initial resonant frequency (i.e. 5.8 GHz) gets shifted to IEEE 802.11ac 5 GHz Wi-Fi band, providing the gain and bandwidth of 11.4 dBi and 510 MHz, respectively. The proposed antenna array has been fabricated, and the measured results are presented to validate the proposed array. Moreover, the equivalent circuit of the proposed antenna array has been designed and analyzed to validate the simulated, measured and theoretical results. Attainment of dual band characteristics by incorporating the metamaterial with single band traditional patch antenna array makes this structure novel, as this has been achieved without any extra hardware cost, size and loss of structural planarity. Also, both the frequency bands of this proposed metamaterial inspired antenna array possess considerable gain and bandwidth.