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本文采用双倒F 振子天线(DIFA)结构设计一种宽带宽方向图天线。双倒F 振子天线不但具有单倒F 振子天线低轮廓、宽波束优点,还具有较宽的阻抗带宽特性。实测显示单元双倒F 振子天线在驻波比小于1.8 的情况下,阻抗带宽大于25%,在0°±85°区域内天线方向图增益≥-2dB。 相似文献
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基于平面倒F 天线模型,设计了一种用于2.4GHz RFID 系统的印刷倒F 单极子天线。采用易于射频集成的微带馈电方式,并结合带线阻抗变换,以实现较宽的阻抗带宽;采用在印刷倒F 结构正上方加载寄生辐射贴片,以提高天线增益。利用高频电磁仿真软件Ansoft HFSS 对提出的天线进行了建模、仿真和优化设计,该天线在2.28-2.51GHz 频率
范围内VSWR<2,达到了10%左右的阻抗带宽,特别在RFID 系统的工作频段内(2.401GHz~2.409GHz)VSWR<1.35, 增益>2.36dBi。该天线具有尺寸小,重量轻,成本低等众多优点,能应用于工作于2.4GHz 的各种RFID 系统中。 相似文献
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刘雯 《电子信息对抗技术》2009,24(6):8-8
宽带天线设计面临诸多困难——尤其是手持终端,需要在工作频段、天线大小、工作模式、增益以及简明化之间进行权衡和折衷。最近香港大学采用了一种新开发的进化优化算法,设计出一种平面超宽带(UWB)单极天线。该天线是平面的多不规则四边形单极天线,尺寸可调,由微带馈线馈电。该天线的特点在于具有倒了圆角的矩形接地阻抗带宽,进一步改善了诸如阻抗带宽等单极性能。 相似文献
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提出了一款用于翻盖手机中的四单元天线。该天线的阻抗带宽可以覆盖无线通信中的两个常用频段。在整个工作频段内的天线单元之间的互耦均小于-10分贝。参数分析给出了关键的结构参数对天线性能的影响。计算得到的相关系数和平均有效增益显示该天线系统能够提供很好的分集性能。 相似文献
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袁峰 《中国电子科学研究院学报》2008,3(3):313-317
给出了一种耦合微带线馈电的印刷单极子天线的设计,可在WLAN的2.4/5.2/5.8 GHz全频段下工作.该天线由耦合微带线馈电对称三角形贴片辐射单元构成,在不同的奇偶模激励方式下均可激励出双频工作.通过仿真分析了该天线在不同模式激励馈电情况下的参数性能表现,并作出了理论上的解释.研究结果表明该天线在两种激励方式下天线各项带宽特性均表现优异,阻抗带宽从普通微带天线或半波振子天线的5%左右提高到20%以上;奇偶模激励方式下的天线方向图有很大不同.该天线设计简单,结构紧凑,可以适用于不同应用场合. 相似文献
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Nakano H. Ikeda N. Yu-Yuan Wu Suzuki R. Mimaki H. Yamauchi J. 《Antennas and Propagation, IEEE Transactions on》1998,46(6):788-793
The effects of parasitic elements on the voltage standing wave ratios (VSWR's) of two antennas are investigated. First, a parasitic monopole is used for a normal-mode helical antenna. The VSWR investigation shows that dual-frequency operation is obtained by the parasitic element effects. The dual-frequency operation is revealed as a function of monopole position above a ground plane (monopole height). As the monopole height decreases, the separation of a higher resonance frequency fH from a lower resonance frequency fL increases. For a monopole length of LMP≈0.4λHX , where λHX is the resonance wavelength of the helix, the frequency bandwidth for a VSWR=2 criterion is 12.5% in the lower frequency fL region and 5.2% in the higher frequency f H region, with a frequency separation ratio of fH/fL=2.14. Secondly, L-figured parasitic elements are used for an inverted-F antenna (IFA). The parasitic elements improve the VSWR performance. The frequency bandwidth for a VSWR=2 criterion is approximately two times as wide as that of the single IFA. It is also found that bending the horizontal sections of the IFA and parasitic elements contributes to reducing the antenna size while not significantly deteriorating the VSWR bandwidth. The radiation patterns are also presented and discussed 相似文献
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《Antennas and Propagation, IEEE Transactions on》2006,54(9):2585-2592
A new class of miniature printed embedded inverted-F antennas are proposed for operation in the 2.4–2.485 GHz wireless local-area network band. One of the proposed antennas on FR4 substrate (dielectric constant = 4.4) measures 9.2 mm by 4.1 mm and has a bandwidth of 3.5%. The peak gain of this antenna is 1.4 dBi. An overall size reduction of 70% is achieved compared to a conventional inverted-F antenna. Effects of dielectric loss tangent and material conductivity on the bandwidth and efficiency of these antennas are also investigated. Finally, two embedded antenna elements are analyzed to demonstrate the feasibility for a decoupled antenna pair consisting of switched and combining diversity schemes. 相似文献
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The aperture-coupled cylindrical dielectric resonator (DR) antenna loaded by a low-profile DR disk of very high permittivity is studied experimentally. By using the low-profile parasitic DR disk the antenna bandwidth can be increased from 8% bandwidth to 25%. The characteristics of the new configuration are measured and discussed 相似文献
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A novel, low-profile internal planar inverted-F antenna (PIFA) with broadband characteristics is proposed for GSM/DCS/UMTS/WiBro applications. Broadband characteristics are achieved by inserting an inverted-L patch, and a bent feed line ensures good impedance matching. The optimum design parameters of the proposed antenna are decided by parametric analysis. Good omnidirectional patterns with reasonable gains are achieved at each frequency band of interest 相似文献
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Meandered multiband PIFA with coplanar parasitic patches 总被引:2,自引:0,他引:2
A meandered multiband planar inverted-F antenna with two coplanar parasitic patches is presented. The antenna has a very wide impedance bandwidth of 743 MHz covering the frequencies from 1.765 to 2.508 GHz with the return loss L/sub rtn/ /spl ges/ 6 dB. The antenna also operates in the GSM band with a high radiation efficiency. 相似文献
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近年来,为解决传统介质谐振器天线(dielectric resonator antenna, DRA)体积庞大等问题,新颖的低剖面DRA如介质贴片天线和平面介质天线被提出并迅速成为研究热点.然而,现有的低剖面DRA设计要么平面尺寸较大(>0.5λ0×0.5λ0),要么带宽较窄(<10%),限制了它们的实际应用.文中提出了一种具有小型化平面尺寸的宽带低剖面DRA.本天线采用介质贴片设计,顶部为高介电常数的介质贴片,中间为低介电常数的介质基板,底部为缝隙馈电结构.缝隙馈电结构可激励起介质贴片谐振器的基模TE111和高次模TE131两种工作模式,这两种模式的场分布在贴片边缘部分存在基模场强较弱而高次模场强较强的显著区别.本设计巧妙地利用了该区域的模式场强区别,通过略微增加贴片边缘部分高度来显著影响高次模谐振频率而轻微影响基模谐振频率,从而将高次模TE131的谐振频率迅速下拉并与基模TE111的谐振频率靠近合并,在不增大介质贴片平面尺寸的前提条件下获得宽带工作效果.本天线的三维尺寸为0.35λ0×0.35λ0×0.08λ0 (λ0为中心频率处的空气中波长),线极化实物案例测试结果表... 相似文献
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A technique is presented for improving the performance of low-profile, circularly polarized (CP) radiating-line antennas. The essential elements of the technique pertain to establishing a single traveling wave on an annular sector of conducting strip that is positioned parallel and close to a large conducting surface. The antenna is named the annular sector, radiating-line (ANSERLIN) antenna. Using this technique, the impedance bandwidth becomes so large that it no longer has any bearing on the operating bandwidth. Instead, the pattern shape and axial ratio become the factors that limit the bandwidth. Both senses of circular polarization can be transmitted or received from the same structure. Experimental results for two-port ANSERLIN antennas are presented. The method of exciting a traveling wave on the annular sector is discussed. Design parameters are given for an antenna that will produce a broadside axial ratio that is less than 0.5 dB at a specified frequency 相似文献
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A reconfigurable stacked microstrip patch antenna is proposed. The antenna operates at an upper frequency fu with a broadside pattern, 7.5-dBi right-hand circularly polarized gain, and 15.8% bandwidth. At a lower frequency fl, the antenna operates as a planar inverted-F antenna (7.3% bandwidth and 3.9-dBi peak gain) with the main beam directed close to the horizon. Switching between the two regimes of operation is achieved using p-i-n diodes. Antenna operation in the upper frequency band is suitable for low-earth-orbit or medium-earth-orbit satellite communications, and in the lower frequency band, the antenna is useful for terrestrial land-mobile or other wireless applications 相似文献