| With the swift evolution of the communication technology,5G technology has been extensively applied in living.It not only brings convenience to people,but also makes the world more colorful.Among them,LTE(long term evolution)band 42(3.4 –3.6 GHz)band in sub-6 GHz band plays an important role in 5G communication system.With the advancement of people's requirements for communication system,the array antenna in the existing 5G communication system is facing the challenges of miniaturization,high isolation and resistance to metal environment.Therefore,the research on the array antenna in LTE band 42(3.4 – 3.6 GHz)band has important theoretical significance and practical value.Taking 5G communication as the technical background and array antenna as the technical basis,this paper studies the characteristics and performance of microstrip array antenna and mobile terminal MIMO array antenna under 5G background,and designs two new array antennas from the perspective of practicability.The main research innovations and work results are as follows:1.A 4×4 microstrip array antenna working in LTE band 42(3.4 – 3.6 GHz)band is studied and produced.The antenna array adopts the method of combining embedded feeding and coaxial feeding.Firstly,the rectangular microstrip patch with embedded structure is used for feeding.By changing the embedded depth and width of the microstrip line,the obtained bandwidth is 373 MHz(3.321-3.694 GHz),and the relative bandwidth can reach 10.7%.At the same time,the embedded structure design also effectively reduces the volume of the antenna.Finally,the whole array antenna uses the coaxial feeding method,and the feeding network is composed of T-type power divider to suppress the coupling between antenna units and achieve the decoupling effect.Therefore,the microstrip array antenna has a high gain of 12.7d Bi,the antenna pattern has no distortion and has good directivity.2.A two element "ring-slot" MIMO antenna applied to 5G metal frame mobile terminal is studied.The design of MIMO antenna in metal framed mobile terminal is facing the challenge of metal environment.Due to the limitation of space,there is a problem of mutual coupling.In order to weaken the interference of the metal frame on the antenna performance,the slot is selected in the metal frame,and the metal frame is used as a part of the feed structure of the antenna.Then,the decoupling principle is analyzed from the perspective of eigenmode theory.The resonant mode excited by ring antenna and slot antenna shares a rectangular floor slot.Without loading any external decoupling structure,the two antenna units are overlapped.It is proved that the isolation of the designed two unit "ring-slot" structure is still higher than 21 d B,and the size is greatly reduced.3.In order to meet the demand of 5G cellular communication system in the future,it is necessary to continuously increase the channel capacity of smart phones.The design trend is to integrate six or eight antenna units.Therefore,an eight-unit MIMO antenna applied to 5G metal frame mobile terminals is designed and produced.The antenna array realizes the coverage of LTE band 42(3.4 – 3.6 GHz)frequency band.The T-shaped decoupling structure is etched on the floor between the adjacent "ring-slot" structures on the two long sides of the antenna to capture the floor current,which effectively improves the antenna performance.By continuously optimizing the "ring-slot " module layout and unit spacing,the overall structure of the antenna is compact and miniaturized.The measurement results show that the isolation of the antenna is greater than 17 d B,The radiation efficiency is 65.8% ? 73.7%,and the envelope correlation coefficient ECC is less than 0.03.Finally,the radiation absorption(SAR)of antenna to human body is analyzed,which shows good MIMO performance.Starting from practical problems,the three antenna arrays designed for 5G communication system show excellent performance,which can provide help for future theoretical research and practical application,and have great potential in 5G communication in the future. |
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