| The application of electromagnetic wave runs through every aspect of our life,and plays an extremely important role in many fields such as military,aviation and communication.It can be said that our life is inseparable from electromagnetic waves.With the rapid development of society and the continuous progress of science and technology,people have higher and higher requirements on electromagnetic wave control precision.How to realize the accurate regulation of electromagnetic wave has also become an urgent problem to be solved.Because of its simple structure,low loss,easy to control and other advantages,the metasurface has been widely concerned by people,and it has great potential in electromagnetic wave regulation.In this paper,several effective methods of electromagnetic wave beam regulation are explored by using the principle of metasurface regulation.The main research content includes the following points:(1)Based on the regulation principle of high order phase mode,a metasurface array structure which can realize different phase modes is designed.On this basis,the beam steering,focusing and generation of orbital angular momentum(OAM)vortex beams is realized.Firstly,the principle of phase control in metasurface is studied,and an array with high order phase mode is designed to control the phase of electromagnetic wave;On the basis of this,the phase conditions for the beam steering,focusing and generation of vortex beams are studied,and the electromagnetic beam with the scanning angle of 110°,the beam focusing at any position and generation of vortex wave with different OAM modes are realized by using the designed high-order phase array.In addition,the feasibility of the structure is verified by simulation.(2)A dynamically adjustable reflective metasurface array structure is designed,and generates OAM beams with mode-reconfigurable and frequency-reconfigurable.The varactor diode is used as the adjustable part of the array element,and the phase of reflected wave is continuously adjustable in a certain band by using the adjustable capacitance of the varactor diode.On this basis,according to the generation principle of vortex electromagnetic wave,the generation of vortex wave with mode-reconfigurable and frequency-reconfigurable by the designed metasurfave is realized.In addition,by means of phase compensation,the divergence of vortex beam is reduced and gain is raised.The purity of the generated vortex beam is calculated,at the same time,the influence of transmission distance and actual machining error on the purity result is analyzed,and its reliability is further verified. |
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