超宽带天线的研究与设计

【作者】 王华；

【导师】 沙侃；

【作者基本信息】 南京理工大学 ， 电路与系统， 2009， 硕士

【摘要】 近年来随着军用和民用通信技术的发展,超宽带天线不断的向小型化和宽频化方向发展。由于超宽带系统频带与其他系统频带重叠而相互干扰,设计具有带阻特性的超宽带天线成为目前研究的热点。印刷单极子天线由于其结构简单,易于加工,带宽较宽等特点受到人们的广泛关注。本文的主要内容主要包括以下几个方面:1.首先介绍了超宽带平面单极子天线的基本结构,并对其基本工作原理进行了讨论,然后针对上述基本结构的不足,提出了在辐射贴片上采用圆角和阶梯化处理,形成了两款改进型的微带馈电的平面单极子天线,仿真结果表明两款微带馈电的单极子天线达到了接近19:1的阻抗带宽。开槽式天线则利用上述两种改进措施,获得了超过了20:1阻抗带宽。然后提出了一种开孔式的平面单极子天线,在整个频段内可实现近似的全向辐射。最后以第一款改进型平面单极子天线的辐射贴片为原型,形成了CPW馈电的超宽带共形天线,仿真结果表明其阻抗带宽接近20:1。2.针对天线小型化设计提出了半CPW馈电的单极子天线,并对结构进行改进,使天线最低工作频率进一步降低,尺寸减少了将近40%,仿真的阻抗带宽范围达到1.99～40GHz。3.为了避免与无线局域网系统频带重叠而相互干扰,在设计的单极子天线中加入了C形缝隙,并对C形缝隙的尺寸及位置都作了相应的研究,并在特定的频段达到了陷波的特性。更多还原

【Abstract】 In recent years, with the rapid development of military and civilian communication technology, the UWB antenna has been developing toward the direction of miniature and wideband. Moreover, to avoid the interference resulting from frequency overlap between the UWB system and other systems, the UWB antenna with band-notched characteristics become research hotspots in antenna field. The printed monopole antennas have received considerable attention owing to their attractive merits, such as simple structure, ease of fabrication and properties of wideband. The dissertation will include the following contents:1. Firstly, this thesis introduces the fundamental structure of the planar monopole antenna and discusses its working principles. Then using the round corners and steps on radiating patch separately, two types of the improved monopole antenna fed by microstrip line are presented. The simulated results demonstrate that the two antennas achieve a ratio impedance bandwidth of 19:1. The slot antenna takes advantage of the two types of the improved measures above, and achieves a ratio impedance bandwidth of above 20:1. Then a hollowed monopole antenna fed by CPW feed line is presented, and the simulated results demonstrate that it exhibits a nearly omni-directional radiation pattern over its whole frequency band. Finally, a CPW-fed conformal monopole antenna with the similar radiating patch of the first improved planar antenna is proposed, and it achieves nearly a ratio impedance bandwidth of 20:1.2. In order to realize the miniaturization, a half CPW-fed UWB monopole antenna is proposed. Some improvements on antenna are introduced to further reduce the lowest frequency of operation, and a significant 40% reduction in size is realized. The simulated bandwidth ranges from 1.99GHz to more than 40GHz.3. In order to avoid the interference from overlapping of the frequency band with the WLAN system, the C-shaped slot into the monopole antenna is introduced. The effects of the different dimension and location of the slot are analyzed, and the proposed antenna has reached band-notched characteristics at certain frequency.更多还原