标题: | 可抑制旁波瓣与改善增益之半模基板合成波导泄漏波天线设计 Techniques for Side Lobe Suppression and Gain Enhancement of a Half Mode Substrate Integrated Waveguide Leaky-Wave Antenna ANTENNA |
作者: | 吕政皓 Lu, Jeng-Hau 周复芳 Jou, Christina F. 电信工程研究所 |
关键字: | 天线;泄漏波;基板合成波导;antenna;leaky wave;substrate integrated waveguide |
公开日期: | 2010 |
摘要: | 使泄漏波天线缩小化并仍能维持应用所需之辐射场型和可以接受增益 是个近年来很具挑战性的天线设计难题。由于泄漏波天线本身是行波天线, 所以于泄漏波天线上,我们会希望只有正向的行进波于天线结构中存在. 于天线结构任何地方引起的反射波都会对于辐射场型有相当程度的干扰; 但是就算反射波可能可以被完全压抑,由于泄漏波天线也可被视为是一种 孔径天线,当一个孔径天线上近场分布是均匀时,我们仍可以理论上预测 有旁波瓣的存在.这几点对于泄漏波天线的辐射场型是需要接受改进之处. 基于以上现象,本论文提出一个转接设计和两个设计方法以助于改善半模 基板合成波导泄漏波天线的辐射场型和增益. 我们首先提出一个转接设计以提升馈入泄漏波天线并激发泄漏波模态 的效率.此设计可以较为有效率的激发泄漏波的模态以压抑于泄漏波天线 端口引起的反射,进而可以避免反射波的激发.此设计对接下来两个设计 方法具有相当程度的帮助. 接下来是提出一个调整半模基板合成波导宽度的方法以达到对旁波瓣 的压抑.由于这个调整方法能够改变于泄漏波天线孔径上的近场分布使其 等效磁流源分布容易满足Taylor’s Rules,故旁波瓣可以因而被压抑. 最后是提出一个回授网路的设计来把泄漏波天线尚未辐射之残余能量 导引回泄漏波天线馈入端.如此可以利用其剩余能量来达到增益的提升. 由于以上设计简易方便,且容易于所需的频率点做设计改良,故其在 应用上有很大的潜力. This thesis gives a study on two techniques to suppress the side lobes and enhance the gain of a half mode substrate integrated waveguide leak wave antenna, respectively. In this thesis, we are aware of two phenomenon that may spoil the performance of a leaky wave antenna: 1. Due to the traveling wave nature of the leaky wave antennas, the remaining power at the end of the leaky wave antenna should always be carefully guided and terminated or the reflected wave will be excited with the corresponding back lobes that may spoil the radiation pattern. 2. Even if one can guide the wave in the leaky wave antenna to avoid reflections, an ideal leaky wave line source may still introduce side lobes due to the effect of the finite uniform illumination of the aperture antennas. We would here give a study on two methods accompanied with a proposed transition dedicated for a half mode substrate integrate waveguide leaky wave antenna to handle the problems mentioned above. First, a transition to efficiently convert the input power to construct the leaky mode of the leaky wave antenna is proposed to enhance the efficiency of the leaky wave antenna and avoid possible reflections at the terminal of the leaky wave antenna. This transition can be considered as a stepping stone to facilitate the later analysis and design of the leaky wave antenna. Secondly, a cosine-shaped tapering profile is proposed to taper the waveguide width of the half mode substrate integrated waveguide. Since one can thus shape the aperture field of the leaky wave antenna to satisfy the Taylor’s rules, the side lobes of the radiation pattern can having a better chance to be suppressed. Finally, a feed-back network is proposed to guide the non-radiated power back to the feed of the leaky wave antenna. The gain is expected to be enhanced with the aid of the non-radiated power. These two methods accompanied with the proposed transition can improve the performance of the leaky wave antenna at an arbitrary frequency range easily and thus has great potential in many applications. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079713594 http://hdl.handle.net/11536/44611 |
显示于类别: | Thesis |
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