Research On The Generation And Scattering Characteristics Of Multi-mode Vortex Electromagnetic Wave

Vortex electromagnetic waves have attracted much attention in domestic and foreign research because of the new degree of freedom that contains orbital angular momentum.In the field of communication,the vortex electromagnetic waves between different modal values are orthogonal to each other,which can achieve multiplex transmission at the same frequency;in the field of radar detection,the phase characteristic of the spiral changes the scattering characteristics of the target.There is potential application value in detection and imaging.However,there are still many problems in the practical application of vortex electromagnetic waves,such as the complex processing technology and the simplification of the generation mode,the energy generation in the main radiation direction,and the unsound theory of scattering characteristics.Therefore,it is very important to study the generation and scattering characteristics of vortex electromagnetic waves.In this paper,based on a uniform circular array,two methods of phase control and time switch sequence are used to generate multi-modal vortex electromagnetic waves.Based on the spectral decomposition and physical optics method,the radar cross section of several calibration objects in the high-frequency region is studied..The main research contents include:First,the basic theory of orbital angular momentum is introduced,and the different characteristics of vortex electromagnetic waves compared to traditional plane waves or quasi-plane waves are summarized.The methods of generating vortex electromagnetic waves are summarized,the advantages of array antennas to generate vortex electromagnetic waves are introduced,and the theoretical models of vortex electromagnetic waves generated by phase control arrays and time switch arrays are given.Secondly,the design of the multi-mode vortex electromagnetic antenna is carried out.Based on the circular patch linearly polarized antenna and the rectangular patch corner circularly polarized antenna,the Ku-band vortex electromagnetic wave is generated by two methods: phase control and time switch.Optimize the array antenna with dual-ring arrays,and consider the antenna consistency,analyze the actual amplitude and phase error on the effect of the vortex;design a sixteen Walkinson power divider as the feed network Perform power transmission to ensure the phase difference between each port and increase the isolation between ports.Finally,a qualitative analysis is made on the scattering characteristics of vortex electromagnetic waves.The vortex electromagnetic wave reception and detection scheme is given;the vortex wave backscattering model is established,and the main mode proportion of the backscattered echo is discussed using the method of spectral decomposition,which is used as the criterion for judging the effect of backscattering vortex.The related theories of vortex wave radar cross section are explored,compared with plane wave radar scattering,the corresponding expression of vortex wave radar scattering is discussed,and the radar scattering characteristics of typical calibration objects such as metal plates and cylinders are analyzed.