Design And Study Of A New Beam Reconfigurable Reflectarray Antenna

With the rapid development of wireless communication technology,as an important component of communication system,antenna has received more and more attention.In order to meet the demand of modern wireless communication with high speed,wide coverage,multi-function and other applications,the fast scanning capability of antenna is required more and more,and at the same time,it also needs to take into account the characteristics of planarization,easy processing and high gain.Reconfigurable Reflectarray Antenna(RRA)combines the advantages of traditional reflectarray antenna and phased array antenna,with the advantages of low cost,low loss,high radiation efficiency and high precision beam control,and has attracted much attention in recent years.In this paper,the research objective is to reduce the reflection loss of electronically controlled RRA,and the design of low-loss variable phase array elements and the trade-off effect of phase quantization are investigated from the viewpoint of switching configuration and phase quantization method.The main work of this thesis is as follows.1、Firstly,the development background of beam scanning antenna and the current situation of domestic and foreign research are introduced,and the working principle of various beam scanning antennas is elaborated from the basic theory.A systematic investigation of beam scanning antenna technology is carried out,and the characteristics of different beam scanning antenna technology designs are analyzed.The reconfigurable method used in the design of RRA under the low-cost constraint is focused on,mainly including the comparison of advantages and disadvantages of different types of switches in the array,the design of bias circuit,the quantization method of phase,the analysis of reconfigurable units,and the problem of cascaded switch superposition loss of electronically controlled RRA units at the present stage is studied.2.Based on the analysis and research of RRA,the traditional line polarized reflector array antenna is used to verify the phase quantization method and the selection strategy of quantization bits,and the influence of different quantization bits on the antenna performance is analyzed and compared.The above effects mainly include the subflap level,gain and beam pointing error.3.A new low-loss reflective array cell structure with directly loaded RF switches is proposed.The switch of reconfigurable unit is directly mounted on the reflector unit,and the design of parallel circuit is adopted to avoid the problem of superposition of each switch loss in the case of more than lbit phase quantization and reduce the insertion loss brought by additional switches.The reconfigurable unit can realize 360° reflection phase change at its operating frequency,and the phase is linearly distributed with the switching of the switches.The reflective loss of the integrated two-pair,four-pair and six-pair PIN diode switches is simulated and compared,and it is found that the number of phase states has limited effect on the reflective loss of the cell,which is conducive to the realization of low-loss reconfigurable multi-phase and makes it suitable for the design of large RRAs.By adjusting the rotation angle of each unit on the reflecting array,the main beam of the array antenna can achieve effective radiation to the far-field scanning range of "±60"°.With 2-bit quantized phase of the array units,the antenna achieves an aperture efficiency of 25.53%,and its beam azimuth error is kept below 2°.