| In the past,radomes often appeared to protect the antenna,and the main research was on how to reduce its impact on the electrical performance of the antenna.With the development of the 5G(fifth generation mobile communication system),and the multiple-input multipleoutput(MIMO)technology has been widely used,this will greatly increase the information transmission rate of the information system and the channel capacity.However,with the continuous development of the technology,the requirements for the antenna system are gradually increased,the antenna design is more and more complicated,and the space left for the antenna design is also limited,at this time,the radome protects the antenna and assists in improving the performance of the antenna.The design method of the radome will be based on the traditional theoretical design and integrated with the metasurface to form a multifunctional radome.This design method not only retains the functions of the traditional radome,but also greatly improves the complexity of the antenna design without increasing the complexity.antenna performance.In addition,the physical environment of future antenna work will be harsher,and the electromagnetic environment will be more complex.The design of the radome needs to be further improved according to the requirements of the antenna,so as to protect the normal operation of the antenna without affecting the overall performance of the antenna.In this paper,by analyzing the design background of the low insertion loss radome,the proposed dual-frequency low insertion loss radome achieves low insertion loss transmission in the C-band(3.3-3.6GHz)and millimeter-wave band(24.25-29.5GHz).The low insertion loss frequency selective surface radome has better heat dissipation than traditional dielectric radomes.By summarizing the research progress of metasurface decoupling,single-layer and double-layer decoupling metasurfaces are designed respectively,all of which have different degrees of coupling suppression effect.The single-layer decoupling metasurface is integrated with the low insertion loss radome,and the formed multifunctional radome effectively improves the isolation between the antenna units of the large-scale base station,and has certain practical value.The radome designed in this paper is mainly used in the base station antenna.The specific work is as follows:1.The analysis method of low insertion loss radome is studied.By analyzing the wave transmission principle of the radome in different frequency bands,a thin-walled radome is designed for the dual-frequency antenna array with wide-angle scanning.The highfrequency antenna is greatly affected by the physical environment,and the height and position of the radome are simulated and analyzed,a dual-frequency low insertion loss radome integrated with C-band(3.3-3.6GHz)and millimeter-band(24.25-29.5GHz)was designed,and the radome was measured.Finally,under the antenna scanning angle of ±55°,it is guaranteed that the insertion loss of the radome in the C-band is lower than 0.5d B,and the insertion loss in the millimeter-wave band is lower than 1.5d B.In addition,the frequency selective surface radome is studied,and a frequency selective radome with high metal ratio and low insertion loss is designed for the C-band antenna.First,a FSS unit with a high proportion of metal is designed,and the insertion loss of the unit is less than 0.21 d B.It is then flattened into an FSS array and connected with a metal ground to form an FSS radome.Finally,the heat dissipation performance of the traditional dielectric radome is compared,which confirms the good heat dissipation performance of the proposed FSS radome.2.Metasurfaces with decoupling effects is studied.The coupling mechanism between different ports of the 1×4 dual-polarized antenna array is analyzed,and a metasurface decoupling method is proposed on this basis.An antenna array loaded with a single-layer metasurface is designed,which not only improves the isolation of the antenna port,but also improves the beam scanning capability of the antenna array.Loaded with a double-layer metasurface antenna array realizes broadband decoupling,and the isolation bandwidth between adjacent elements is greatly broadened compared to loaded single-layer metasurface.On this basis,the two forms of decoupling schemes are processed and measured,and the results confirm the correctness of the designed decoupling method.3.The integration method of metasurface and sandwich radome is studied.Expand the antenna size of 1×4 to 6×4,in which the non-scanning surface is connected by a power divider.In addition,the metasurface and the low insertion loss A sandwich radome are integrated into a multifunctional radome and placed on a 6×4 antenna array.Finally the isolation of formed antenna system is greater than 20 d B between all different ports in the range of 3.3-3.6GHz,and can complete beam scanning in the range of ±55°. |
