Development of Software Tools for Design and Production of Mobile Communication Microstrip Antennas

在本研究项目中，完成了一些用于设计和研制复杂微带型天线的计算机仿真工具。其主要特点如下：1.提出了一种新的微带天线辐射分析的数值和理论方法。该方法将一种新的场辐射模式展开理论与传统的FD-TD(时域有限差分法)相结合。这种方法对于分析具有无限大介质衬底和接地导体的微带型结构的场行为是非常有效的。以往的方法如矩量法、有限元法和纯FD-TD法都很难处理这类结构。2.针对主要由圆形和圆柱形状组成的天线和散射体，开发了一种基于FD-TD方法的新的仿真工具。该方法可称为柱坐标FD-TD法。为了使这种方法非常有效，有必要在柱坐标系中发展所谓的PML(Perfect Match Layr)吸收边界条件。这项工作提交给了Trans.IEICE(B-II)。3.将上述第一项中描述的新方法应用于单片微波集成电路(MMIC)的直角弯曲元件的分析，以说明该方法的有效性。最后，必须指出的是，由于未来生产移动通信设备的电子公司预计将需要用于更复杂的电路(如三维MMIC)的设计工具，因此仍有许多相关的研究课题有待承担。

In this reserach project, some computer simulation tools for designing and developing complicated microstrip type antennas have been completed. The main features are summarized as the following :1.A new numerical and theoretical method for analyzing radiation from microstrip antennas has been developed. This method uses a newly devised theory of radiation mode expansion of field combined with conventional FD-TD (Finite-Difference Time-Domain) method. This method is very effective to analyze field behaviors in microstrip type sturctures with dielectric substrate and ground conductor of practically infinite size. Such structures have been very difficult to be treated by the previous methods such as Moment Method, Finite Element Method, and pure FD-TD method.2.A new simulation tool based on the FD-TD method has been developed to treat very accurately antennas and scatterers whose shapes are mainly composed of circular and cylindrical shapes. The method may be called the cylindrical coordinate FD-TD method. To make this method very effective, it was necessary to develop the so-called PML (Perfectly matched Layr) absorbing boundary condition in cylindrical coordinate system. This work was submitted to Trans.IEICE (B-II).3.The newly developed method described in the above item 1 was applied to the analysis of right-angle bend element of MMIC (Monolithic Microwave Integrated Circuits) to show the usefulness of the present method. The results were summarized and submitted to IEEE Trans.on Microwave Theory & Tech.Finally, it must be mentioned that a lot of related research subjects still remain to be undertaken because electronic companies producing mobile communication equipments are expected in future to require designing tools for much complicated circuits such as three dimensional MMIC.