Design method of low-profile and small antenna for mobile communication.

由微带贴片（MSA）或其他印刷天线组成的低剖面小型天线在移动的通信系统中被广泛用作高效的辐射器。本文介绍了移动的系统中低剖面小型天线的设计技术。测试天线由0.6 mm厚的低损耗聚四氟乙烯（Teflon）光纤包铜制成，天线的厚度为10 mm，天线的厚度为10 mm。玻璃基板，介电常数为2.55，损耗角正切为0.0018。本研究的主要内容如下：1.在天线的小型化中，估算无载Q（Q_0）、辐射效率η和频带宽度BW是很重要的。本文计算了典型基片（Teflon玻璃纤维基片）的短接MSA的η和BW随基片厚度（h/λ da_0：λ da_0：自由空间波长）的变化。在对天线的eta和BW进行测量时，测量值与计算值在设计所需的范围内吻合良好，天线方向图的测量值也与计算值吻合良好.为了评估这种低剖面和小天线的性能，一些测试样品的构造和测试在微波区。实验结果表明，该天线的方向图和椭圆度与理论结果吻合较好，表明该天线可以作为移动的通信系统的单元天线.最后，通过将大量的这些小天线集成，制成低剖面平面阵列。测试平面阵列的实验图案与理论图案一致。因此，这里提出的天线被认为是有效地适用于作为低剖面和小天线的移动的系统。

A low-profile and small antenna consisting of microstrip patch (MSA) or other printed antenna are widely used as an efficient radiator in mobile communication systems.This report presents the designing techniques of low-profile and small antenna for mobile system.The test antennas were made of a copper-clad 0.6 mm-thick low-loss Teflon fiber-glass substrate with a dielectric constant of 2.55 and loss tangent of 0.0018. The important items of this investigation are mentioned briefly as follows.1. In miniaturization of an antenna, it is important to estimate unloaded Q(Q_0), radiation efficiency eta and frequency bandwidth BW.The values of eta and BW for shorted-MSA are calculated for a typical substrate ( Teflon fiber-glass substrate ) as a function of substrate thickness ( h/lambda_0 : lambda_0 : free space wave-length ). On measuring the values of eta and BW, all the measured values agreed well with the calculated ones within desirable ranges for designing.The measured patterns of the antenna agreed also well with the computed results.2. In order to estimate the performance of this low-profile and small antenna, some test samples were constructed and tested at the microwave-region. As expected, the experimental pattern and ellipticity of the antenna agreed well with the theoretical ones.These results indicate that the low-profile and small antenna is applicable as an element antenna for mobile telecommunication system.3. Finally, the low-profile planar array was made by integrating large numbers of these small antennas. The experimental pattern of the test planar array agreed well with the theoretical one. The antenna presented here is, therefore, considered to be effectively applicable as a low-profile and small antennas for mobile system.