| With the development and application of 5G technology,active large-scale adaptive multi-beam array antennas have become the development direction and research focus of5G base station antennas and maritime satellite communications,and massive MIMO conformal arrays and beamforming technologies are extremely critical.This paper has carried out research work on the cylindrical conformal array antenna used in 5G communication.The main contents are:1.For 5G base station antennas in different application scenarios,a linearly polarized antenna and three types of circularly polarized antennas with different performances are designed.Among them,a wide beam linear polarization antenna,two wide beam circular polarization antennas,a high gain circular polarization antenna,and a dual frequency circular polarization antenna.The wide-beam linearly polarized antenna achieves beam spreading by loading diagonal metal pillars and reducing the size of the bottom plate.The impedance bandwidth is 3.38?3.62 GHz,and the H-plane 3 d B beamwidth is 113.3~o.The wide beam and circular polarization antenna 1 achieves expansion of beam width by loading a screw-like monopole,and its bandwidth is 4.75 to 5.05 GHz.The 3 d B beam width is widened to more than 161~o,and the axis width less than 3 d B is greater than 172~o.The wide-beam antenna 2 widens the beam width by loading a metal cavity and a conductor wall,and its bandwidth is 4.3?5.6 GHz.The 3 d B beamwidth on the main plane is greater than 115~o,and the 3 d B axis ratio beamwidth is greater than 139~o.The wide-band and high-gain circularly polarized antenna 3 based on the V-shaped slot coupling feed has an operating bandwidth of 2.9?3.82 GHz,covering the 3.5 GHz frequency band in the 5G spectrum.The average gain in-band is 8.22 d Bi.A double-fed and double-layer patch structure is used to achieve dual-frequency circular polarization.The working frequency bands of antenna 4 are 2.54?2.67 GHz and 3.41?3.59 GHz,and the axial ratio is less than 3 d B in the frequency bands of 2.6 GHz and 3.5 GHz.The low-frequency gain reaches 3.65 d Bi,and the high-frequency gain reaches 6.5 d Bi.2.Using the wide-beam antenna 2 as the array element,a circular polarization phased linear array with a 1×6 wide-angle scanning was designed.After optimization,the simulation and actual measurement results show that the in the 4.5-5.3 GHz frequency band,the scanning range of main beam of the line array reaches-57~o?58.5~o,the gain fluctuates of main beam by a maximum of 2.3 d Bi during the scanning process,and there is no scanning blind spot.Four 1×6 phased linear arrays are formed into a square column conformal array to achieve an over range of circularly polarized beam coverage,which can be applied to signal coverage in remote and sparsely populated rural and suburban areas.In addition,using a broadband high-gain circularly polarized antenna as the array element,a24×6 cylindrical conformal array antennas are designed.By using beam switching and scanning technology,a circular pole can be generated in the range of 360~o in the azimuth plane and 56~o in the elevation plane.The beam coverage has the characteristics of target tracking and strong anti-interference ability,and it is suitable for urban areas with many buildings and dense population.3.The structural design and beamforming algorithm of cylindrical conformal array are studied.By comparing the arrangement of three cylindrical arrays,the array model structure is finally determined.Based on the idea of subspace division,the space ranges to be covered is divided into 24 subspaces,and at the same time,reconfigurable technology is used to divide 24 subarrays corresponding to one-to-one.In addition,the working principle and advantages of the bat algorithm are introduced.Based on the standard bat algorithm,two major improvements are made:adding new inertial weights and adaptive acceleration factors,and dynamic quantum revolving gates.In addition,considering the coupling effect between the array elements,in the improved bat algorithm,the active pattern(AEP)data of all array elements is imported to make the beamforming closer to the actual situation.For further verification,the excitation information(amplitude and phase)of each array element fed back by the algorithm is acquired into CST for verification.The CST verification result is basically consistent with the result of beamforming. |
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