Study on Design Method of Antennas Used for Mobile Telecommunications

1.本文提出了一种利用导体散射体内部区域的绿色函数的简单有效的方法。该方法已被应用于分析位于导电矩形柱上的二维磁源和位于导电盒上的三维缝隙天线，这是典型的内置天线用于便携式电话。对于二维情况，即使在内部区域假设任意源时，通过引入最小二乘法也得到了精确的结果。在三维问题中，再次得到了精确的结果，并证实了该方法具有程序简单、计算机运行时间短等优点.用传统的伽辽金矩量法进行了分析，并与新方法的结果进行了比较。虽然采用了最小二乘法，但新方法的计算机运行时间约为传统伽辽金矩量法的十分之一。从而证实了新方法的优越性.为了改进上述方法1，引入了变分原理。结果表明，该方法提高了计算精度，大大减少了计算机运行时间（约为方法1的十分之一）。因此，这种方法被认为是有用的便携式电话天线的有效设计方法。然而，寄生共振也被观察到，需要进一步的研究来克服这个问题。一个内置的天线（S形天线）的便携式电话已实验开发。已研制出800MHz便携式电话用的8cc天线。

1. A simple and efficient method which make use of the Green's function in the interior region of conducting scatterer has been proposed. This method has been applied to analyses of two-dimensional magnetic source located on a conducting rectangular cylinder and a three-dimensional slot antenna located on a conducting box which is the typical built-in antenna used for portable telephone. For the two-dimensional case, the accurate results have been obtained by introducing the method of least square even when arbitrary sources are assumed in the interior region. In the three-dimensional problem, the accurate results have been again obtained and the great advantages such as a simple procedure and a short run time of the computer have been confirmed.2. The conventional Galerkin-moment method analysis has also been carried out and the results have been compared with those by the new method. Although the method of least square has been used, the run time of the computer for the new method is about one tenth of that for the conventional Galerkin-moment method. Thus, the advantage of the new method has been confirmed.3. In order to improve the method 1 mentioned above, variational principle has been introduced. The results show that the accuracy is improved and the run time of the computer is greatly reduced (about one tenth of that of the method 1). Thus, this method is considered to be useful for an efficient design method of antennas for portable telephone. However, spurious resonances have been also observed and a further investigation is necessary to overcome this problem.4. A built-in antenna (S-shaped antenna) for the portable telephone has been experimentally developed. A very small (8cc) antenna has been obtained for portable telephone at 800MHz.