Research And Design Of Broadband Dual-polarization Base Station Antenna For 5G Communication

Presently,the development of the fifth-generation mobile communication system has entered a new stage.The 5G frequency band dominated by Sub-6GHz has become the main application frequency band at present.At the same time,the rapid development of 5G communication systems has brought about problems such as the lack of space resources due to the surge in the number of base stations,the high deployment cost of base stations and how multiple communication standards coexist.Both low-profile broadband dual-polarized base station antennas and multi-frequency dual-polarized base station antennas are good solutions to the above problems.They can not only work in multiple communication frequency bands at the same time,saving space resources and costs,but also can effectively resist the influence of multipath fading and improve the communication quality.They have become the object of extensive research in the current industry and academia.Therefore,research on them applicated in 5G communications has very important research value and practical significance.The specific research contents of this thesis are as follows:1.Aiming at the problems of base station deployment cost and lack of antenna resources,a dual-polarized base station antenna element that can achieve a wide frequency band and low profile was designed.By loading the loop cross dipole to achieve good matching and wide bandwidth,while loading the AMC reflector to reduce the profile effectively.After measuring,the antenna element can achieve the high port isolation of more than 35 d B in the working frequency band of 3.1-5.2 GHz,the low profile(0.12?)and the stable radiation performance(65°±5°).Then,a five-element lowprofile antenna array was designed using the above-mentioned low-profile antenna element.The simulated results show that,in addition to the Cross-polarization Discrimination Ratio(XPD),the antenna array can achieve wide bandwidth(3.25-5.1GHz),high port isolation(25 d B),high gain(15 d Bi)and relatively stable radiation pattern(V-plane 13°±3°,H-plane 65°±5°).2.Aiming at the low XPD of the five-element low-profile antenna array,crosspolarization suppression structures were designed and loaded on the five-element array.In addition,the operating principle and design process of the structures were analyzed in detail.By measuring the prototype of antenna loaded these structures,the cross polarization of the antenna array was effectively suppressed,and the XPD was greater than 29 d B in the operating frequency band of 3.14-5.32 GHz.Moreover,the port isolation was greater than 28 d B,the half-power beam width of V and H plane is 13°±3°and 65°±5°,respectively.The antenna array had good electrical performance and stable radiation performance.3.Aiming at the limitations of previous high and low frequency-nesting schemes,a dual-broadband dual-polarized base station antenna array suitable for current 5G communication base stations was designed.Firstly,a bowl-shaped low-frequency antenna element with a radiation diameter of only 127 mm × 127 mm was designed.Through technical methods such as widening the width of the dipole and bending,a wide frequency band(0.69-1.03 GHz),high port isolation(>30 d B)and stable radiation performance were realized.Secondly,based on the low frequency element and the above high frequency element,a new nesting scheme was proposed.Five high-frequency elements were placed inside two low-frequency antennas and between two low-frequency antennas in an unevenly distributed manner.Finally,through the optimization of highfrequency reflectors,loading high-frequency isolation walls to reduce the mutual influence between high-and low-frequency antennas.The simulated results shown that the antenna array can cover two frequency bands of 0.69-0.96 GHz and 3.3-5.0 GHz simultaneously,the isolation of high and low frequency ports were greater than 31 d B and 20 d B,respectively.Moreover,the good radiation performance was achieved at the same time.In summary,the low-profile broadband dual-polarized base station antenna arrays and dual-wideband dual-polarized base station antenna arrays were proposed in this thesis.They can effectively solve the current problems in the design of 5G base station antennas,and provide a reference for the design of base station antennas.