Research On Improvement And Design Of Miniaturized Dual-polarized Base Station Antenna

Today's mobile communications are developing rapidly.With the establishment of 5G licenses issued by my country's Ministry of Industry and Information Technology to China Mobile,China Telecom and China Unicom,it marks the official start of 5G commercial use.Since the mobile communication system is a long-term process in the evolution process,the previous 2G/3G/4G will continue to be used by people for a long period of time.Therefore,the working frequency band of the mobile communication system will become wider and wider,and the performance requirements will become higher and higher.At present,the minimum requirement for the base station antenna is still that its operating frequency band needs to cover 2G/3G/4G(1710-2690MHz).Considering the frequency of the antenna's operating frequency bandwidth,the traditional dipole antenna is more suitable.In order to improve the communication capacity and solve the shortage of site resources,the application of multi-beam antennas enters people's field of vision and approaches the civilian field.Based on the above background,this paper has carried out research and design on the miniaturization,broadbandization and multi-beam base station antennas of dual-polarized base station antennas in mobile communication systems.The research work of this paper is as follows:1.Based on the square dipole,using its own characteristics,the square dipole is folded inward.The cross-sectional area of the dipole antenna is effectively reduced,and the 4G LTE communication frequency(2500-2700MHz)is realized by adjusting the impedance of the coupling feed structure.2.The multi beam antenna working in the frequency band of 2500-2700 MHz is studied and designed.Through theoretical analysis and simulation,the parameters of horizontal and vertical plane are determined.In order to obtain better circuit performance and radiation performance,the array form is optimized.A 3×5 Butler matrix network is designed for the shaping of the horizontal plane,and the three beams in the horizontal plane have accurate beam direction.The vertical plane shaping adopts one-third unequal power division network,which can effectively suppress the sidelobe level,and realize the vertical plane preset down angle.3.Two planar polarization PCB base station antenna units are designed with different feeding forms.In the first one,a new resonance mode is added at the higher frequency near the working frequency band by introducing a Y-shaped branch inside the dipole,and the impedance bandwidth of the dipole is widened by introducing a new resonance mode.The second one is based on the linear dipole,which adopts the differential feeding method.The method of introducing the parasitic metal patch on the top of the antenna effectively widens the impedance bandwidth of the antenna.The bandwidth of both antennas can completely cover 1710-2690 MHz communication frequency band.