Research On Dual-polarization Wide-Angle Scanning Phased Array

Recently,with the rapid development of mobile communication systems,on the one hand,spectrum resources are becoming increasingly scarce.For this reason,researchers proposed to use high-frequency millimeter wave band(30?300GHz)to alleviate this problem;on the other hand,the wireless communication signal transmission process will have problems such as multipath fading,and dual-polarized antennas have polarization agility and polarization.The advantages of diversification and simultaneous transmission and reception can be used to resist multipath fading.To this end,this thesis takes the dual-polarization phased array antenna working in the millimeter wave band as the object to study the wide-angle scanning capability of the array antenna and expand the effective working bandwidth,suppress the scanning side lobe level,and reduce the scanning cross-polarization component.The main research contents are as follows:1.A dual-polarized phased array antenna of ±45° millimeter wave with aperture coupling feeding is proposed.The array element antenna is composed of three main parts:a dielectric metal cavity,a multilayer radiating patch,and a bottom feed network layer..The working frequency band of the antenna unit is the Ka band with a relative bandwidth of 12%.The antenna unit also exhibits wide beam characteristics(the half-power beam width of the main polarization plane is about 145°),high port isolation(>21dB),and low crossover.Polarization level characteristics(about-30 dB).The 16×4 phased array composed of the antenna performs scanning,and the coverage of the scanning beam reaches ±75°,and the side lobe level during scanning is lower than-7.5dB with good scanning characteristics.In addition,the paper evolves the above-mentioned 16×4 dense array into a sparse array,that is,half of the T/R components.The array antenna also has better scanning characteristics.2.Based on the above-mentioned millimeter wave dual-polarization model,further study the completely separated structure of the radiating patch and the feed network,so that the antenna has higher port isolation and low cross-polarization characteristics.The working frequency band of this antenna model is 3.5GHz?3.7GHz,and the antenna has high port isolation characteristics(>35dB)and low cross-polarization level(about-35 dB).The S-band dual-polarized antenna is constructed into 8×8 and(8×8)/2 phased arrays to realize wide-angle scanning.In addition,the S-parameters and radiation pattern of the processed prototype were tested,and it was found that they were in good agreement with the simulation results.