| Microstrip antenna has many advantages, such as small size, light weight, low profile, easy aircraft conformal and easy processing. However, the defect of narrow-band performance limits the applications of microstrip antenna. It is essenctial to develop broadband design methods for enhancing the bandwidth of circularly polarized microstrip antenna.The methods to improve the circular polarization microstrip antennas’s bandwith are studied, and two kinds of broadband circularly polarized microstrip antennas are proposed. The main work of this dissertation is as follows:(1)Firstly, this dissertation discusses the basic parameterrs of the microstrip antenna and the methods for analysis of microstrip antenna as well as enhancing microstrip antenna’s wideband performance.(2)Secondly, based on the theoretical research, this dissertation analyzes the principle of broadband circularly polarized microstrip slot antenna’s performance. A wide-shaped gap circularly polarized microstrip antenna is proposed. The simulation and experimental results indicate that the antenna has a wide bandwidth and circular polarization characteristic.(3)Thirdly, according to the analysis of single point feed, double points feed and four points feed circular polarization microstrip antenna, a structure of three points feed microstrip antenna is proposed. Then this dissertation studies on the methods to improve the circularly polarization microstrip antennas’s bandwith, and infers the condition of n (n>=3) points feed antenna for achieving circular polarization performance. Finally the simulation results of circular polarization microstrip antenna feed by three points are given; the results show that the microstrip antenna has a good circular polarization performance. |
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