Design And Experimental Study Of Multi-Mode OAM Wave Antenna

With the development of wireless communication technologies and the increasing demand for communication rates,high-speed information transmission has been fully developed in wireless communication.Today's information transmission and detection systems,such as microwave communication and radar,are based on the development of planar electromagnetic wave propagation mechanisms.After years of research in the code domain,frequency domain,time domain and airspace,a lot of improvement in the utilization of spectrum resources has been obtained.But it has gradually approached the theoretical capacity ceiling.Theoretically,the OAM wave has an infinite number of mutually orthogonal topological loads,which can improve the communication rate by means of modal multiplexing.And provide a possible development direction for new communication technologies.Due to its vortex phase characteristics,OAM waves have become a possibility in the field of detection.In this paper,an eight-mode OAM wave antenna is designed for the requirements of wireless communication for multi-mode OAM wave antenna,and the vortex phase characteristics of the OAM antenna are tested.Aiming at the problem of OAM wave diffusion angle,a method to reduce the OAM wave diffusion angle is proposed and verified by simulation.This paper mainly includes the following three aspects:1.A multi-ring microstrip OAM wave antenna unit is studied for the miniaturization of multi-mode OAM wave antenna.The antenna unit is based on the principle of a high-order mode patch method,and eight OAM wave modes are generated by four shorting rings.The simulation software is used to simulate the OAM mode of the antenna,and the feasibility of the antenna is verified.The antenna is physically tested by means of an external feed network.The test results show that the eight OAM wave modes maintain good vortex phase performance.2.A close-range wavefront phase test system is designed for the closerange transmission of the eight-mode OAM wave antenna.The system is used to test the OAM wave antenna for 12 m outdoor.The test results show that the OAM wave antenna can maintain the vortex phase characteristics in the far field,laying a foundation for the OAM wave mode transmission.3.A method to reduce the vortex electromagnetic wave diffusion angle is designed for the problem of the OAM wave diffusion angle.Since the diffusion angle of the OAM wave antenna is related to the aperture and the mode of antenna,the Fabry-Perot(FP)resonator can be used to indirectly increase the aperture of the antenna to reduce the diffusion angle.The influence of the cavity parameters on the vortex beam of the antenna is analyzed by simulation,and the feasibility of the method is verified.