Design Of Vortex Wave Antenna Based On Circularly Polarized Antenna Array

With the advent of 5G era,information interaction between people is becoming more and more intensive,and the number of mobile Internet users is increasing exponentially,which makes people have higher requirements for information transmission rate and communication system.In order to meet the current demand of high-speed communication,more spectrum resources will be occupied,resulting in the shortage of spectrum resources in the field of wireless communication.As a new type of freedom,the electromagnetic wave carrying Orbital Angular Momentum(OAM)has great potential to improve spectrum efficiency and channel capacity,which has attracted much attention of people.In this paper,a series of researches are carried out on the design of vortex wave antenna of circularly polarized antenna array.The main work is as follows:(1)This paper gives a brief overview of the development of vortex electromagnetic wave and its relevant theoretical knowledge is introduced.The theoretical derivation of generating vortex electromagnetic wave by circularly polarized antenna array is carried out,which lays a certain foundation for the feasibility of subsequent design experiments.(2)A wide-beam circularly polarized microstrip antenna whose operating frequency at S-band(2-4GHz)is designed.The antenna adopts coaxial feeding,the parameters of the antenna structure are simulated and optimized by the CST software,and then the overall size of proposed antenna is 0.416?0×0.416?0×0.026?0,the 3-dB axial ratio(AR)bandwidth is 3.78?3.83GHz and operating bandwidth is 3.74?3.95GHz.At the axial resonance frequency f=3.8GHz,the AR beamwidth of 185° and 209°are obtained in xoz and yoz plane,respectively.The proposed antenna has excellent polarization performance in operating frequency,besides,it has simple and compact structure which is easy to implement.(3)The designed circularly polarized antenna is used as an array element.By controlling the rotating direction and angle of the element,the vortex electromagnetic waves with different modes are generated.The influence of different circularly polarized modes and element numbers on vortex electromagnetic wave is studied.By constructing a vortex wave experimental system,the designed antenna array is processed and measured.The results show that the array can generate the electromagnetic wave carrying OAM in the working frequency band,which indicates that the proposed design has a good practical application potential in the field of wireless communication.