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

在这项研究中，我们阐明了天线等辐射元件的电磁现象。给出了满足天线尺寸条件的天线单元的设计方法，并利用时域技术实现了期望的性能指标。此外，我们还证明了该方法对于评估天线特性是有效的。背腔式缝隙天线被认为是一种适合于许多应用的元件，它是我们研究的目标。我们得到了如下新的结果：1.提出了一种基于时域有限差分法的腔背缝隙天线输入特性和辐射方向图的计算方法。我们还提出将时间窗和同轴模型应用于输入特性的估计，并证明了其有效性。在此基础上，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SPS2000尺寸和天线性能要求的天线单元。它的进料器非常简单，位于腔体的底面，并以低轮廓的腔体几何形状实现了所需的特性。所研究的馈线是一个短路探头和一个倒F单元，在未来的研究中需要考虑的课题是天线单元间互耦的估计和波束控制性能，以及小型腔背缝隙天线的研制。

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.