Design Of 5G Base Station Array Based On Microstrip Antenna

In recent years,with the rapid development of the 5th-generation mobile communication system(5G),the existing communication frequency band below 6 GHz has become crowded,and millimeter wave because of its short wavelength,can also have good propagation characteristics in bad weather,making it become the future wave mobile communication carrier choice.Therefore,people turn their attention to the millimeter wave band.It is the trend of the future development of mobile communication to utilize the wide spectrum resources of the millimeter wave band.The millimeter-wave communication system has the advantages of small device size,compact structure,safe communication and high quality of information transmission,which to a large extent makes up for the deficiency of 4G communication.In general,the gain obtained by the antenna unit is relatively low.Modern base stations have increasingly high requirements for the antenna,and it is difficult for the antenna unit to meet these conditions.Therefore,it is necessary to assemble the antenna unit into an array through arrangement.Aiming at the requirements of high gain in 5G base station antenna,this thesis studies the microstrip antenna working at 28 GHz by adopting the slot coupling feed mode,and finally designs three different antenna arrays.The main research contents of this thesis are as follows:First,a double-polarized microstrip slot coupling antenna unit is designed,which is composed of two orthogonal H-shaped slots.By adjusting the size of the slot and the radiation patch,the antenna performance is analyzed.The patch is grooved to compare the antenna performance of three different shapes,and finally the shape with grooves all around is adopted.Based on this,a 1×8 antenna array and power distribution network are designed.The operating bandwidth of the antenna array is greater than 4 GHz,the isolation degree between ports reaches 30 d B,the cross-polarization ratio is greater than 32 d B,and the gain reaches 18 d Bi.The test results are in good agreement with the simulation results.Second,we design a dual polarized microstrip antenna unit back cavity,compared to dual-polarization microstrip antenna aperture coupling unit,remove the air layer,reduced the height profile makes the antenna structure more compact,change not symmetrical H form gap to center symmetrical two wing crack,the far field pattern is symmetrical,in the bottom of the new added back cavity structure inhibits backward radiation.Based on the element,a 1×8 antenna array is designed.The operating bandwidth of the antenna array is greater than 4 GHz,the isolation degree between ports is up to 25 d B,the cross-polarization ratio is more than 20 d B,and the gain is up to 15.4 d Bi.Thirdly,a planar array antenna fed by SIW slit coupling is proposed based on the design principle of SIW slit array and microstrip slit coupling antenna.Compared with the antennas in the previous two chapters,the antenna has the advantages of low loss and low Q value.In this thesis,SIW slot array is used as the feed network.SIW has the advantages of low profile,easy processing,low loss and easy integration with flat circuit.A 1×4 linear array antenna is designed,and then a 4×2 planar array antenna is designed by combining it with the SIW one-bisect in-phase power divider.The operating bandwidth of the array antenna is greater than 3.5 GHz,the cross-polarization ratio is greater than 35 d B,and the maximum gain is 14.3 d Bi,which realizes the low profile characteristics.