Design Of Multi-Band Antennas Applied To 5G Mobile Terminals

With the continuous development of 5G mobile communication,the design of MIMO antennas for mobile terminals is becoming more and more important.For MIMO antenna systems,the miniaturization of the unit,the isolation between the units and the number of units are important issues in the design.This paper studies several antenna systems that can be used in mobile terminals,including three types of MIMO antennas for 5.5-inch screens and two antennas for smart watches.Firstly,the miniaturization research and design of the MIMO antenna suitable for the 5.5-inch screen was carried out.In order to improve the isolation,the structure of the defect was studied.In order to expand the bandwidth of the low frequency band of the antenna,the bending groove,the square groove and the Lshaped branch were also used.The structure was studied.The three types of antennas are designed as 6×6 MIMO antennas,and the-10 dB operating band is 3.3-3.4 GHz,3.4-3.6 GHz and 4.8-5 GHz,and the isolation between each port can be better than 12.3dB.The efficiency can be greater than 60% in the frequency band,and the envelope correlation coefficient between each unit is less than 0.1,which can meet the requirement of less than 0.5 in the communication system,and the average effective gain of each unit changes less than 1dB in its frequency band,and the average between the units The difference between the effective gains is less than 3 dB.Theoretically,the channel capacity of the 6×6 MIMO antenna is 34 Mbps/MHz.After calculation and analysis,the channel capacity of each unit of the actually designed antenna is about 30 Mbps/MHz in its frequency band,which is very close to the theoretical value.At the same time,the paper also simulates the loading of its practical environment such as hand model and head model.The results show that the antenna performance is good.Secondly,the smart model antennas working in 2.4GHz WiFi,Bluetooth and 5GHz WiFi frequency bands are analyzed and designed by the characteristic mode theory.The simulation results are obtained,which proves that the characteristic mode theory is effective in antenna design.The way to provide more convenient guidance for the antenna design simulation process.At the same time,the actual use environment of the antenna was also modeled and simulated.The results show that the antenna performance is goodThe above MIMO antenna system and smart watch antenna were simulated and optimized by CST simulation software,and three types of MIMO antennas were physically processed and tested by Agilent N5227 A vector network analyzer.The test results and simulation were compared.The results show that the two are in good agreement,which proves the correctness of the designed antenna.