Study on Analysis of Electromagnetic Phenomena Using Time Domain Technique Based on Maxwell's Equation

在这项研究中，我们澄清电磁现象的辐射元件，如天线。我们还开发了天线元件的设计方法，满足条件的天线尺寸和实现所需的性能，使用时域技术。此外，我们表明，该方法是有效的评估天线特性。背腔式缝隙天线被认为是一种适用于许多应用的元件，是我们在这项研究中的目标。我们得到了如下新的结果：1.我们发展了一种基于时域有限差分法的背腔缝隙天线的输入特性和辐射方向图的评估方法。同时，我们也提出了应用时间窗和同轴模型来估计输入特性，并证明了其有效性。给出了绝对增益和辐射方向图的分析方法。2.研究了一种满足太阳能卫星SPS 2000天线尺寸和性能要求的天线单元。它具有位于腔底平面的非常简单的馈线，并通过低轮廓腔几何形状实现所需的特性。研究的馈线是一个短路探针和一个倒F元件。未来的研究应该考虑的主题是天线元件之间的互耦和波束转向性能的估计，以及低剖面背腔缝隙天线的发展。

In this study we clarify electromagnetic phenomena of radiating elements such as an antenna. We also develop the design method of antenna elements that satisfies conditions of the antenna dimension and realizes desired performance using the time domain technique. Moreover we show that the method is effective to evaluate the antenna characteristics. A cavity-backed slot antenna that is considered as an element suitable for a lot of applications is our target in this study. We obtained the new results shown below.1.We developed an evaluation method of input characteristics and radiation patterns of the cavitybacked slot antenna using the finite-difference time-domain method. Also we propose to apply the time windowing and the coaxial model for the estimation of input characteristics, and show its effectiveness. Furthermore we show the analytic method of absolute gains and radiation patterns.2.We investigate an antenna element that satisfies the dimension and antenna performance required for the solar power satellite SPS2000. It has the quite simple feeder located in the bottom plane of the cavity and realizes the desired characteristics with the low-profile cavity geometry. The investigated feeders are a shorted probe and an inverted-F element.The subjects that should be taken into account in future studies are the estimation of mutual coupling among antenna elements and the performance of beam steering, and the development of the low-profile cavity-backed slot antenna.