Design And Experimental Verification Of Dual-mode And Dual-polarization OAM Multiplexing Antenna

To cope with the increasing shortage of spectrum resources in wireless communications,orbital angular momentum(OAM),which can provide a new multiplexing dimension following time,space,code type and frequency,has attracted worldwide attention.Electromagnetic waves carrying orbital angular momentum are also called OAM waves.By constructing multiple orthogonal communication channels in the state space of OAM,multiple OAM waves with different OAM modes can be transmitted simultaneously within the same bandwidth.OAM waves are expected to greatly increase the system capacity and to solve the problem of frequency resource shortage without increasing the system bandwidth.In this thesis,the relationship between OAM mode multiplexing and polarization multiplexing is studied.Firstly,a dual-mode single-polarization OAM multiplexing antenna is designed based on the method of generating OAM wave by circular array antenna.The simulation results show that the antenna designed in this thesis can generate multiplexed OAM waves of OAM mode l=+1 and OAM mode l=+2 at 2.4 GHz.Secondly,a dual-mode dual-polarization OAM multiplexing antenna is simulated,designed and then measured after combining OAM mode multiplexing technology and polarization multiplexing technology.The simulation and experimental results prove that the designed antenna can generate multiplexed OAM waves of x-polarization,OAM mode l=-1,x-polarization,OAM mode l=+1,y-polarization,OAM mode l=-1 and y-polarization,OAM mode l=-1.The dual-mode dual-polarization multiplexing OAM antenna works at a broad bandwidth of 2.6GHz-3.1GHz.Furthermore,using the orthogonality of different beams generated by the antenna,a co-frequency transmission experiment is realized without adding additional coding and decoding algorithms and other multiplexing methods.The simulation and experimental results verify the orthogonality between different modes of OAM waves,and prove the feasibility of using OAM multiplexing technology to improve communication capacity in communication systems.Communication experiments based on a USRP software radio platform verify the orthogonality between polarization multiplexing and OAM mode multiplexing,which lays a foundation for the combination of OAM mode multiplexing and other multiplexing technologies.