| In recent years,the development of wireless mobile communication is advancing by leaps and bounds.In only half a century,mobile communication has developed from the first generation mobile communication system(1G)to the fifth generation mobile communication system(5G).The commercial application of 5G mobile communication system puts forward more requirements for the performance of base station antennas.Nowadays,±45° dual-polarized cross dipole antennas are more widely used in base station antennas.At the same time,because both base station and mobile phone need to support the latest 5G mobile communication system and Beidou receiver,both Beidou antenna and 5g base station antenna are needed.As one of the global navigation satellite systems,Beidou satellite navigation system(BDS)not only provides positioning services,but also supports short message service communications.Beidou satellite navigation antenna which is in line with the performance of miniaturization,wide axis ratio bandwidth,low cost and easy processing has always been the focus of research.Four-arm spiral antenna is widely used in Beidou satellite navigation system because of its wide radiation beam.The specific research work is as follows:1.A broadband dual-polarized planar base station antenna unit for LTE/5G base station is proposed.The antenna uses two vertically crossed dipoles to achieve±45° polarization.The antenna uses a new square ring-shaped metal stub as the feed structure,which realizes the complete planarization of the antenna and reduces the physical size of the antenna as much as possible.Then the impedance matching bandwidth of the antenna is increased by slotting on the dipole arm and parasitic elements.The test results show that the bandwidth of the antenna is about 44.1%(2.3-3.6GHz)when the S11/S22 parameter is less than-15dB,and the isolation between ports is better than 25dB.The half-power beamwidth of the dual-polarized antenna is about 65±5°,and the gain increases gradually from 8.25dBi to 11dBi at 2.3-3.6GHz.2.A printed quadrifilar helix antenna working in Beidou-B3 band is proposed.Compared with the traditional quadrifilar helix antenna,the use of the printed flexible circuit board structure greatly reduces the complexity of the antenna structure,reduces the difficulty of antenna processing,and the most important thing is to improve the stability of the antenna structure.The test results show that the impedance matching bandwidth of the antenna near the central frequency point is more than 60MHz.The 3dB width of the axial ratio at the central frequency point of the B3 band is about 210 degrees.The circular polarization effect of the antenna is good,and the RealizedGainRHCP of the antenna is 3.95dB,the half-power beamwidth is about 145 degrees.Its radiation pattern is in the shape of a heart.3.A combined application of 5G broadband dual-polarization base station antenna and Beidou printed quadrifilar helix antenna is proposed.The simulation results show that the axial gain of the Beidou printed quadrifilar helix antenna antenna increases from 3.94dBi to 4.39dBi,and the 3dB beamwidth of the radiation pattern increases by about 10 degrees.At the same time,the 3dB beam width of the radiation pattern of the 5G broadband dual-polarized base station antenna is also increased by about 10 degrees.Therefore,the combined structure not only enables it to work in two scenes at the same time,but also effectively increases the half-power beamwidth of its radiation pattern,which has important research significance. |
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