Research On Generation And Multiplexing Of OAM Waves Using Antenna Array

OAM(orbital angular momentum)waves have two different characteristics from plane wave:modes orthogonal and spiral wave fronts.Due to its unique characteristics,OAM waves can be used to improve the spectrum efficiency and channel capacity in wireless communication system,improve the azimuth resolution of the target in radar detection and the rotational Doppler effect of detection target.OAM waves have strong application prospect in these fields.Thus,OAM waves have been widely concerned by many scholars in the domestic and overseas.A lot of work has been done on the generation and application of OAM waves.In this thesis,by summarizing the existing research work,we analyze the theory of OAM waves generated by antenna array,study the generation and multiplexing technology of OAM waves and study the application of OAM waves.The contents of this thesis are listed as follows.OAM waves generated by antenna array are studied.Aiming at the OAM waves generated by antenna array,the principle of OAM waves generated by three kinds of antenna array is given.The differences of radiation patterns and electric field components' distributions of three kinds of OAM waves based on theoretical formulas are studied,and the best way of generating OAM waves is obtained.Firstly,the formula results show that the electric fields generated by the three antenna arrays carry different Bessel functions and OAM phase factors,which result in different characteristics of OAM waves.Then,the characteristics of radiation pattern,phase distribution,amplitude distribution and energy distribution of OAM waves are simulated based on formulas,and compared with the simulation results in CST based on modeling.The comparative analysis shows that the theory is in good agree with the simulation results.OAM waves generated by the same direction antenna array have the optimal characteristicsThe multiplexing method of OAM waves is studied.Aiming at the problem of OAM waves multiplexing,the orthogonal characteristics between different modes of OAM waves generated by same direction antenna array are analyzed.It is found that the modes of OAM waves are not pure,which will lead to the phenomenon of non orthogonal between OAM modes.The conclusion provides guidance for the design of multiplexed-OAM-mode antenna.On this basis,the design of multiplexed-OAM-mode antenna based on planar same direction antenna array is proposed for the first time.The characteristics of reflection parameters,radiation patterns,phase distributions and isolation between the multiplexed-OAM-mode antennas are simulated.Then the design of the multiplexed-OAM-mode antenna is determined.Then,further processing and testing of the proposed antenna are carried out The experimental results show that the designed multiplexed-OAM-mode antenna can generate two OAM modes successfully and achieve the design goalInformation transmission,target detection,and combination of communication and detection based on OAM waves are studied.First of all,aiming at the problem of multi-channel information transmission at the same time,the two-way video information transmission based on the multiplexed-OAM-mode antenna is carried out under the experimental framework of information transmission.The experimental results show that the multiplexed-OAM-mode antenna can achieve two-way information transmission simultaneously at the same frequency band and improve the channel capacity.Then,the rotation Doppler shift based on the OAM waves produced by same direction antenna array is proposed.For the detection of the Doppler effect of the target rotation,the rotating speed of the metal disk is tested.On this basis,the rotating speed test experiment of the rotating blade is carried out.The experimental results display that OAM waves can detect the rotating speed of the rotating blades,and can get the distribution law of metals in the blades.It is proved that OAM waves can improve the resolution of the detected contour.Finally,according to the application requirements of communication detection integration,the experiment scheme of communication detection integration is designed.The rotation speed of the target object measurement and information transmission are carried out at the same time.The application prospect of the mode orthogonality of OAM waves in the integration of communication and detection is verified preliminarily.All in all,OAM technology has potential application value in the future information transmission,target detection and communication detection integration,and it is worth further in-depth research.