Design Of Broadband Dual-polarized Base Station Antenna For Mobile Communication

With the increase of information transmission,the mobile communication system becomes more complex.The innovative communication system fully promotes the development of base station antenna technology.At present,the base station antenna is developing towards broadband,multi-band and miniaturized for the application of multi-system co-antenna and co-station.The requirements of base station antenna design become more strict under the complex application environment.Furthermore,the dual-polarized antenna is the best choice for base station antennas because it can resist multipath fading and increase the capacity of communication system.Synthetically considering the performance of the base station antenna,this paper focuses on the design of broadband and high-performance dual-polarized base station antenna for mobile communication.The main contents are as follows:1.A dual-polarized base station antenna is designed and fabricated.The antenna consists of a pair of orthogonal planar dipoles with U-shaped slots,T-shaped feeding lines,Metallic Cylinders,coaxial lines and a rectangular metallic plate reflector.The wider frequency band can be realized by the mutual coupling between the two dipoles.The measured results show that the relative bandwidth of the antenna is 56.3%(1.58GHz-2.82GHz),and the port isolation can reach 30 dB.In the working frequency band,there is a stable pattern and a low cross polarization level.In addition,a four element antenna array is designed with this antenna as the element,which can meet the design requirements of the current 2G/3G/LTE application.2.The in-phase reflection phase characteristic of the AMC structure can be used to reduce the profile height of antennas.In order to realize the miniaturization design of the dipole base station antenna,this paper proposes an improvement on the traditional AMC structure without conducting vias.And an AMC structure with a lower operating frequency and a wider bandwidth is designed.The 0 degree reflection phase frequency is near 2.2GHz,and the in-phase reflection relative bandwidth is 64.9%(1.56GHz-3.06GHz).3.In this paper,the rectangular metal reflector of the previous dual-polarized base station antenna is replaced by the improved AMC structure.The joint simulation design of AMC structure and base station antenna is realized.The overall height of the antenna loaded with AMC is 18 mm,which is 50% lower than that of the previous antenna.Compared with the other same type antennas,the measured results show that the proposed antenna can achieve wider bandwidth.It can cover 1.65GHz-2.81 GHz,and the relative bandwidth is 52.3%.Furthermore,the antenna has a low profile,high isolation(>30dB)and low cross polarization level(<-27dB).On the basis of the antenna element,a four-element antenna array with AMC structure is designed and studied,which provides a reference for the design of the dual-polarized base station antenna.In summary,the two types of dual-polarized base station antennas proposed in this paper are in line with the development trend of broadband,miniaturization and low cost,and can meet the requirements of current mobile communication applications.