A study on the effect of unbalance current on antenna measurement

• Main Authors: Chen,Cheng-Chang, 陳誠章
• Other Authors: Ching-Wen Hsue
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/41094470942735869200

碩士 === 國立臺灣科技大學 === 電子工程系 === 93 === Since the size of the ground plane is decreased to be comparable to a wavelength, the ground plane should be a planar radiator. Therefore, the antenna combined with its ground plane is similar to an asymmetric dipole antenna. The unbalanced current is induced on the feeding coaxial cable consequently. The influence of unbalanced-current, or common-mode radiation, studied in this thesis is discussed in EMC firstly, but, however, it is a significant problem in modern antenna measurement because of the size of the ground plane. The topics studied in this thesis are as follow. First of all, the influence of the unbalanced-current is studied in the summery of references and experiment results, respectively. In this part, it gives that solving of the influence is imperative. After that, some examples of the solution are provided in theoretical and experimental analysis. Ferrite chock studied in this part firstly is a typical a choice in EMC, since it is efficient operated lower than 1GHz. However, in current portable devices, the operation frequency range is not sufficient. Consequently, two sleeve balun are induced in this thesis, a traditional single band sleeve balun and a novel dual-band sleeve balun.