【作者】 张丽娜；

【导师】 钟顺时；

【作者基本信息】 上海大学 ， 电磁场与微波技术， 2011， 博士

【摘要】 随着频谱资源的不断开发和使用,宽带、小型化与双极化等技术在未来无线通信系统中变得越来越重要,尤其在卫星通信、电子对抗等国民经济和军事应用领域。为此本论文提出了宽带、双极化介质谐振器天线与超宽带、圆极化平面天线等多项创新性设计,并完成了相应的实验验证。论文主要包括以下几方面内容:第一,提出了一种U形结构的宽带介质谐振器天线,从理论上分析了该结构介质谐振器的谐振模式,并研究了两种馈电贴片结构。实验结果表明,采用椭圆形贴片馈电和采用倒三角形贴片馈电的U形介质谐振器天线的相对阻抗带宽分别达到72%和84%,处于国际先进水平。第二,研制了高隔离度双极化介质谐振器天线。通过采用对称馈电和反相馈电等技术,有效地改善了双极化介质谐振器天线的端口隔离度和交叉极化电平。其两极化端口的实测隔离度优于42dB,并实现了主瓣内天线的交叉极化电平低于-21dB,该性能已超过现有国际文献报道的结果。此外还设计了S/X双波段双极化介质谐振器天线和微带天线的混合型天线阵。第三,研制了UWB全向平面单极天线。通过分析辐射贴片形状和馈电结构对天线方向性的影响,提出矩形辐射贴片和双点馈电结构来改善天线的全向特性。同时提出在馈线中嵌入调谐枝节实现对WLAN频段的阻带特性。理论仿真和实测结果表明,该天线在UWB频段内具有良好的全向辐射特性。第四,提出了L形枝节馈电的圆极化分形平面缝隙天线,并分析了一阶和二阶分形结构的正菱形缝隙天线。一阶分形正菱形缝隙天线与不采用分形缝隙的天线相比,具有较宽的阻抗带宽,相对阻抗带宽为50.4%(3.74GHz-6.26GHz),轴比小于3的相对带宽为13.3%(4.9GHz-5.6GHz);而二阶分形的缝隙天线具有较小的尺寸,在最低谐振频率相同的情况下,二阶分形缝隙天线仅为一阶分形缝隙天线尺寸的67%。更多还原

【Abstract】 With the spectrum resources being developed and applied, the techniques of wideband, miniaturization and dual-polarization are increasingly important in the wireless communication system in the future, especially for national economy and military applications, such as the satellite communications, electronic warfare systems, etc. Thus this dissertation proposes the novel designs of wideband and dual-polarization dielectric resonator antennas and ultra wideband (UWB) and circular-polarization planar antennas with experimental verification. Four main subjects are included:Firstly,A kind of U-shaped dielectric resonator antennas is proposed. The resonator modes of this dielectric resonator configuration are anslyzed in theory, and two patch-fed structures are studied. From the experiment results, the elliptical patch-fed and inverted trangle-fed U-shaped dielectric resonator antennas have 72% and 84% impedance bandwidths, respectively. These bandwidth performances keep advanced level in the world.Secondly, a high-isolation dual-polarization dielectric resonator antenna is developed. By using the symmetry feed and the anti-phase feed technology, the level of port isolation and the cross-polarization level both of the dual-polarization dielectric resonator antenna are improved. The measured isolation between two ports are higher than 42dB, and the measured cross polarization level in the main lobe is less than -21dB, which are being the advanced level in the available international literature. In addiation, an S/X dual-band dual-polarization hybrid array of dielectric resonator antenna and microstrip antenna is designed.Thirdly, the omni-directional ultra-wideband planar monopole antenna is developed. By analyzing the effect of the shapes of radiation patch and feed structure to the radiation pattern, the rectangular patch and the dual-feed structure are proposed for improving the omni-directional characteristic. At the same time the tunning stub embedded in the microstrip feed line is proposed to realize the band-notch. From the simulated and experiment results, the proposed antenna achieves the good omni-directional radiation performance. Fourthly, the L-shaped stub-fed circular-polarization fractal slot antenna is proposed, and the one-order and two-order fractal rhombus slot antennas are analyzed. One-order fractal rhombus slot antenna has a wider impedance bandwidth of 50.4% and AR bandwidth about 13.3%(4.9GHz-5.6GHz), comparing to that of the slot antenna without fractal structure. Under the same circumstances of the same resonance frequency, two-order fractal slot antenna has smaller size, with 67% size reduction compared with the one-order fractal antenna.更多还原