| With the rapid development of fifth-generation communication systems(5G),the communication bands below 6 GHz are becoming more and more crowded,and the wide spectrum resources in the millimeter wave band can alleviate this problem.However,the loss of millimeter wave is relatively large,and often requires array beamforming techniques to improve the gain and compensate for the impact of loss.In addition,the problem of multipath fading occurs during the transmission of wireless communication signals,and dual-polarized antennas,as an important application of polarization diversity technology,can combat multipath fading.For this reason,this paper investigates the dual-polarized antenna with wide angle domain coverage in 5G millimeter wave band:1.Research on broadband wide-beam dual-polarized base station antenna unit for 5G n258 band applicationFor the target of large angle coverage of 5G millimeter wave base station,three wide beam antenna units are designed.Firstly,a multilayer circular patch gap coupled structure±45° dual polarization microstrip antenna unit is designed,this antenna has the advantage of simple structure and easy processing and integration.Secondly,we designed a wide-beam±45° dual-polarized antenna with high isolation in a layered angle-fed structure,which has the advantage of achieving high port isolation in a compact and small size structure,as well as wide bandwidth and wide beam performance.Finally,a cavity structure low mutual coupling wide beam ±45° dual polarization antenna is designed,which has the advantage of suppressing the inter-array coupling without sacrificing the floor integrity and antenna profile.The-10 d B impedance bandwidth of all three antennas can cover the 5Gn258 band,and the beamwidth can reach 120°.2.Research on dual-polarized antenna line array and beam scanning applied to 5G n258 band.Firstly,a 1×8 line array with a multilayer circular patch gap-coupled wide-beam microstrip antenna as the array element is designed.In the bandwidth range of n258 band,the normal gain reaches 13.6 d Bi,the gain decreases by 3 d B at the main beam scanning angle of ±55°,the sub-polarization level decreases to-8 d B,and the cross-polarization ratio decreases to 10 d B.Two power dividers with equal amplitude and equal amplitude and different phase are designed to verify the gain and directional map in the normal direction and the maximum scanning angle respectively.The measured results of the line array are in good agreement with the simulated results,and the wide-angle scanning performance of the array is verified.Next,a 1×16 line array with a layered angle-fed high-isolation antenna as the array element is designed.The bandwidth can cover 5G n258 band range,the port isolation is better than 17 d B,the normal gain of the line array is 17.3 d Bi.the main beam gain is decreased by 3 d B scanning to ±52°,the side flap level is deteriorated to-10.2 d B,and the cross-polarization ratio is 13 d B.3.Research on dual-polarized antenna surface array beam scanning and decoupling structure applied to 5G n258 band.Firstly,the decoupling measures of the defective ground structure are designed for the multilayer circular patch gap-coupled structured surface array.Loading decoupling structure makes the isolation between the polarization ports of the dual-polarization antenna array improved by 4d B,and the scanning angle is improved by 5° during the beam scanning of the large-scale surface array with this decoupling structure.Next,two face arrays,4×4 and8×8,are designed with a dual-coupled fed wide-beam dual-polarized microstrip antenna as the array element,and due to the symmetric structure,beam scanning is performed only in two directions,φ =0° and φ =45° degrees.In the 4×4 array,the normal gain is 14.2 d Bi,the main beam drops 3 d B,and the scanning angle is ±55° along the φ =0° plane and can be scanned up to ±64° along the φ =45° plane.In the 8×8 array,the normal gain is 20.0 d Bi.The main beam drops 3 d B and scans along the φ =0° plane at ±58°,and along the φ =45°plane at ±59°. |
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