Research Of 5G Ultra-wideband Dual-band Massive MIMO Electrical Down-tilt Antenna Array

Generally,5G(5th generation mobile communication)network adopts massive MIMO antenna arrays,which forms 64TR(transmit and receive channel,composed of three elements)output through at most 192 monopolarized units to meet the requirements of macro coverage.Since the three major domestic operators occupy the high and low 5G spectrum among 2.5-3.6GHz broadband respectively,and the base station tower resources are increasingly exhausted in the continuous expansion,the integration and co-construction of Ultra-wideband(UWB)antenna arrays which are dual-band,are required to alleviate the resource dilemma of the towers.On the other hand,the three operators form double 64 TR output in two spectrums,which brings about the cost,weight,energy consumption and heat dissipation of equipment.So it is required to merge the two channels into one channel through the power division network,and introducing phase shifter to realize the electrical down-tilt function.It means compress them into double 32 TR output while satisfying the electrical performance.According to the above requirements,this thesis intends to carry out the research of 5G Ultra-wideband dual-band massive MIMO electrical down-tilt antenna array suitable for 2.515-2.675 GHz and 3.4-3.6GHz frequency bands.In this thesis,the dual-64 TR channel antenna arrays,which include 5G UWB radiation unit,combiner and isolation strip,and the phase-shifting feeding network system,which includes phase shifter and power divider network,are studied respectively.So the dual-32 TR channel massive MIMO electrical down-tilt antenna array is realized.Firstly,the folded dipole structure and orthogonal balun microstrip feeding are used to realize the 2.3-3.8GHz broadband characteristic of the antenna array.By designing the scheme of combining three elements into one subarray and introducing a dual-frequency combiner,massive MIMO antenna array with dual-64 TR channel is realized;by designing the filtering characteristics of the combiner and the spatial decoupling characteristics of the isolation strip,the practical application requirements of the antenna array index are met.Then,for the phase-shifting feeding network system set on the back of the antenna,this thesis uses the integrated dual-cavity structure to realize the miniaturization of the phase shifter,which combines Wilkinson power divider and bridge device to achieve a simple structure conducive to automatic production and welding.By introducing the feeding network between two groups of the three-element-subarrays,the dual-64 TR output is compressed into dual-32 TR output.The compact structure and miniaturization of the antenna array are realized,which not only ensures the electrical performance requirements of the antenna,but also reduces the cost and weight of the base station system.Finally,according to the simulation,a 5G UWB dual-band,dual-32 TR channel massive MIMO electrical down-tilt antenna array prototype is manufactured.The measured results meet the application requirements.Compared with single frequency band 5G electrically tunable antenna,the antenna proposed in this thesis not only meets the coverage requirements for 5G bands of the three major domestic operators,but also has more competitive advantages in cost and practicability,which is in line with the national strategy for co-construction and sharing.The product has been mass produced and put into 5G network applications,which has good application value.