| The design method of the UHF-band circular polarization antennas is presented in this paper. It includes two parts in this thesis: 1. UHF-band crossing dipoles circular polarized antennas are designed; 2. UHF-band Archimedean spiral antenna with wide beam-width and circular polarization is designed.Firstly, UHF-band crossing dipoles circular polarization antennas fed with two type forms are presented: one is coaxial feed, another is a combination of lumped microstrip line-fed method. The circular polarized antennas are simulated and optimized by commercial EDA software Ansoft HFSS. Then the antenna with UHF-band, wide beam-width and circular polarization is made.On this condition, the prototype of the antenna is constructed and measured. The proposed antenna has characters that VSWR is less than 2, beam width is more than 80°and axial ratio performance is good. The measured results agree well with simulated ones, and the design is valid.Secondly, the design method of the airborne Archimedean spiral antenna is presented. Archimedean spiral antenna is simulated and optimized by commercial EDA software Ansoft HFSS. The simulated results show that the characters of this antenna are enough to satisfy the application. On this condition, the prototype of the antenna is constructed and measured. The designed antenna working in UHF-band has the characters that VSWR is less than 1.5, beam width is more than 80°and axial ratio performance is good. The measured results agree well with simulated ones. The measured results show that the Archimedean spiral antenna is of wide beam-width and circular polarization. In addition, the measured results show that this design method is valid and it can be applied. |
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