Design Of Dual-polarized Base Station Antenna In 4G/5G Mobile Communication

With the development of mobile communication system,there are higher requirements of communication capacity and communication rate.As an important part of mobile communication system,the performance of base station antenna has a great effect on wireless communication quality.Base station antennas for 5G frequency bands are becoming a research hotspot with the coming of fifth generation mobile communication system.Meantime,the communication modes of 2G,3G,4G and 5G will develop together in the future.In this thesis,the background and significance of base station antenna are introduced first.And then the development status and fundamental theory of base station antenna are presented.With the help of electromagnetic simulation software HFSS,considering the need of 4G/5G mobile communication,we designed four dual-polarized base station antennas based on fundamental theories of base station antenna.Firstly,a differentially fed dual-polarized slot antenna with low profile and high isolation is designed for base station application.The antenna operates on 3.3-3.6GHz band of 5G sub-6GHz band and the fractional bandwidths of two ports are more than 19.3%?VSWR<1.5?.The profile of this antenna is 0.13?₀ and the isolation between two ports is larger than 43dB.In addition,stable radiation patterns are obtained with half power beamwidth stabilizing 64±3°and high gain of 8.1dBi.The second antenna designed in this thesis is a broadband dual-polarized monopole base station antenna based on differential feeding.The antenna unit is composed of four broadband operating semicircle monopoles utilizing differential feeding technique.The fractional bandwidth is more than 66.7%?VSWR<1.5?which can cover the frequency band of 2G/3G/4G and IMT-1.4GHz/1.5GHz?1427-1518MHz?and the isolation is larger than57dB in the operating band.The half power beamwidth keeps in 68±4°and the gain is more than 8.6dBi.Considering that the multiple antenna technology can increase channel capacity,a broadband six-port dual-polarized base station array antenna with electric downtilt function is designed.The antenna operates on 1710-2690MHz band with VSWR<1.5 and the isolation is larger than 28dB.The optimized reflector structure helps to achieve half power beamwidth of 65±10°,cross polarization ratio at boresight of more than 13dB,cross polarization ratio within±60°of more than 7dB and front to back ratio of larger than 23dB.The vertical radiation pattern with 2-12°electric downtilt is realized and the upper side lobe suppression is around 15dB.Finally,we designed a broadband miniaturized dual-polarized shared-arm dipole base station antenna.The interfacing dipole arms are connected together and C-shaped stubs are loaded.The antenna radiator size is 0.367?₀×0.367?₀×0.293?₀??₀ is the free space wavelength at center frequency point 2.2GHz?.The isolation is larger than 33dB within the operating band 1710-2690MHz?VSWR<1.5?and the gain is more than 7.8dBi.