| With the innovation and rapid development of modern wireless communication technology,the information communication between human beings is almost out of the limitation of distance and time.Antenna,as an indispensable basic component of wireless communication system,is an important conversion device for electromagnetic radiation and electromagnetic wave reception.At the same time,under the premise of ensuring the good electrical performance of the antenna,in order to meet the development needs of the miniaturization of the wireless communication system,the research and design of the miniaturization of the antenna is also particularly prominent and urgent.In view of the above situation,this paper focuses on the design,analysis and application technology of miniaturized wide beam circularly polarized antenna in wireless communication system.Three small circular polarization antennas with different wide beam characteristics are proposed and designed,and the miniaturization theory and research design of the antenna are committed to ensure the full coverage of the radiation beam in the upper half space.The three miniaturized antennas have good wide beam characteristics,good circular polarization characteristics and stable antenna structure.The main contents and achievements of this paper are summarized as follows:First,combined with the research technology of miniaturized circularly polarized microstrip antennas,a compact circular polarized microstrip patch antenna with broadband and wide beam characteristics at 1.1GHz center frequency is proposed and designed.The antenna has a 3d B axis ratio beam width which can cover almost the entire upper half space;the series network with no resistance is used;the slot size coupling and the new triangular radiation patch method are used to reduce the antenna size,and the size of the slot is properly reduced.It is very effective for miniaturization;the three corner patch can effectively reduce the size of the antenna further smaller than the traditional strip patch.The antenna also achieves good circularly polarized characteristics in the horizontal direction.Finally,the electrical size of the antenna is 0.44?×0.275?×0.073?,where the?represents the wavelength corresponding to the central frequency in the vacuum,and has stable matching characteristics and radiation characteristics on the effective bandwidth of the 23%.On this basis,the current distribution and radiation characteristics of the antenna are studied and discussed in detail.Secondly,based on the above theory of microstrip antenna,the design technology of circularly polarized cross antenna is studied.Based on the discussion of the general characteristics and basic requirements of circularly polarized antennas,the annular bridge and highly integrated broadband balun are used to feed the bandwidth of the microstrip antenna.The circularly polarized characteristics of the microstrip antenna are improved,and the circularly polarized characteristics are obtained by broadening the bandwidth.The antenna effectively solves the problem that the antenna is difficult to achieve good impedance matching when miniaturized,and obtains a circularly polarized cross beam antenna with stable radiation characteristics.The 3d B axis ratio of the antenna is larger than 90 DEG and has miniaturization characteristics.Finally,the research background of the four arm helical antenna is fully introduced and the theoretical basis is analyzed in detail.A simple compact circular polarized four arm helical antenna is designed.The antenna abandonment of the traditional ceramic column loading structure,using air loading form,and effectively using the series coupling matching branch,achieves good matching characteristics and has stable radiation characteristics at the same time.Through simulation and optimization,the effective bandwidth of the antenna is 10%,the 3d B axis ratio is over 200 DEG,and a good right-handed circular polarization is achieved. |
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