Studies on Broadband Circularly Polarized Monopole Antennas

• Main Authors: Zhi-Hong Zhou, 卓智弘
• Other Authors: Ghung-I. G. Hsu
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/48402208543667088488

碩士 === 雲林科技大學 === 通訊工程研究所碩士班 === 99 === This thesis presents a broadband circularly polarized（CP）printed monopole an-tenna can be applied to satellite communications system operations, and to improve the antenna gain by a back cavity design. The main features of the monopole antenna with CPW-fed a L-shaped feeder is folded, a circular metal patch, and then implanted the perturbation of a rectangular structure under the circular metal patch. Extension of the design steps to adjust the number of parameters, the antenna radiation characteristics to produce RHCP, and with more than 35 % 3 dB axial ratio bandwidth. In addition, to improve the antenna gain, we propose a second antenna, placing a back cavity behind the monopole antenna. The back cavity is constucted with a metal plate the metal wall on the four edges of the metal plate. Through this simple design and easy to make, we can still get more than 90 % of the original CP bandwith. However, the antenna gain increase over 5~7 dB of the antenna gain.