On The Wide-beam Circularly Polarized Antenna And Shortwave Yagi Antenna

The research work of the thesis is made with scientific projects, the design methods of the wide-beam circularly polarized antennas is presented, and the content of the thesis can be briefly summarized as follows:Firstly, the engineering prototypes of antennas with wide-beam and circular polarization. Secondly, the research work is about the monopole Yagi antennas.Firstly, two design methods of the antenna are presented with the engineering requirement of wide-band and circular polarization. One project is the Archimedes antenna, the design method of Archimedes antenna and balance fed way are simulated by the software HFSS, which is in the FIA basis. The measurement results indicates that the VSWR is less than 1.9 and the gain is more than-1dB in±600.According to the simulation results, the engineering prototypes are made and measured. The measurement results agree well with simulated ones. Another project is the crossing dipoles antenna, which is simulated by the software HFSS. According to the simulation results, the engineering prototypes are made and measured. The measurement results indicates that the VSWR is less than 1.8, and the beam width is more than 1200. The measurement results agree well with simulated ones, and the design is valid. Finally, choose the crossing dipoles antenna as the ultimate project.Secondly, the research of this thesis is the monopole Yagi antennas. According to the requirement of the project, laying simple mechanical and redesigning the monopole Yagi antennas improve the transmit efficiency, which is simulated by the software HFSS. The measuring results indicates that the VSWR is less than 2 and the gain is more than 8dB, the beam width of the horizontal plane is more than 1200, and that of the vertical plane is less than or equal to 640. The obtained results have well satisfied the requirements of the project and achieved the expected design purpose.