A Study On Electromagnetic Scattering Of Orbits Angular Momentum Waves Close To A Interface

With the rapid development of wireless communication technology,orbital angular momentum electromagnetic wave has attracted great interest of scientists in the field of radio communication and radar detection due to its special helical phase characteristics.However,due to the divergence of orbital angular momentum electromagnetic wave in long-distance transmission,the application of orbital angular momentum electromagnetic wave in the field of communication has gradually slowed down.However,in the field of short-range target detection,the research of orbital angular momentum is very hot.Using the interaction between orbital angular momentum electromagnetic wave and short-range target,as well as the field intensity and phase information of scattered orbital angular momentum electromagnetic wave under different conditions,to detect short-range target has become a new research direction.The main contents of this thesis include:1.The basic theory of orbital angular momentum electromagnetic wave is systematically introduced.Then,based on several methods of generating orbital angular momentum electromagnetic wave introduced,the orbital angular momentum electromagnetic wave is generated by an eight-element patch antenna array placed uniformly around the circumference.The phase information of orbital angular momentum corresponding to the mode value is obtained by simulation,which verifies the range of the mode value of orbital angular momentum and the phase structure of the helix.2.The amplitude and phase information of the scattering field of the orbital angular momentum electromagnetic wave and the plane wave are compared and analyzed respectively.Then the amplitude and phase information of the scattering field of the near-surface scatterer are compared,and the feasibility of the orbital angular momentum electromagnetic wave in the detection of the near-range target is obtained from the amplitude and phase information of the field.3.The scattering field of the scatterer is comprehensively analyzed in five aspects: different mode values,different scatterer distances,different offset positions of the scatterer,different sizes of the scatterer and different media of the scatterer when the orbital angular momentum electromagnetic wave is used to detect the short-range target.The law of detection of the short-range target under the corresponding conditions is found according to the amplitude and phase information of the scattering field.4.By analyzing the scattering field of near-surface targets,the effects of orbital angular momentum electromagnetic wave on the detection of near-surface targets in different depth of scatterers,different migration of scatterers,different environmental media and different scatterer media are obtained.According to the scattering field intensity and phase information of the scatterer under different parameters,the corresponding change trend is obtained.The results show that the orbital angular momentum electromagnetic wave has better identification than the plane wave in the field analysis of near-range target detection.The scattering analysis of the scatterer to the orbital angular momentum electromagnetic wave shows that the orbital angular momentum electromagnetic wave is feasible in the detection of near-range target.