Research On The Generation Theory And Techniques Of Flying Electromagnetic Toroid Pulses Based On Antenna Array

As a finite energy impulse solution of Maxwell's equations,Flying electromagnetic toroid pulses(FET)has many unique characteristics.For example,The shape of FET is similar to a doughnut.Its energy covers only a limited range on the plane perpendicular to the propagation direction.Besides,FET has a wide frequency spectrum,and the frequency spectrum distribution varies with the space.What's more,FET also has a non-diffracting waist,and has a strong longitudinal field component on the propagation axis.Because of these unique characteristics,FET has potential applications in accelerating particles,exciting new particles,imaging with high depth of field,building new ultra-wideband communication systems,and localized energy transmission.However,due to its complicated polarization and frequency spectrum distribution,FET has not been produced in practice.Therefore,studying the generation of FET has important theoretical and application value for the application of FET.In view of the current difficulties faced by FET from theory to practice,this thesis firstly studies the basic characteristics of FET,and explores the theoretical feasibility of using antenna arrays to generate FET.Then a specific array design is given.A transverse electric(TE)FET generator and a transverse magnetic(TM)FET generator are proposed and systematically simulated,respectively.Then the TE FET generator is experimentally verified.The main contents are as follows:1 ? Firstly,the related theoretical research is carried out for the purpose of generating FET from antenna arrays.The propagation characteristics of FET in ideal free space and the propagation characteristics of FET under non-ideal boundary conditions are studied,respectively.Then,the characteristics of FET in time domain and frequency domain are introduced in detail,and the field distribution and spectrum distribution of FET at various positions are given,which provides detailed data for generating FET based on antenna arrays.After that,the self-repairing characteristics of FET are studied.Then the propagation of FET under different discrete degrees of excitation is simulated,and the quality factor parameter FOM(Figure of Merit,FOM)is defined.Finally,the self-repairing characteristics of FET under discrete excitation are shown in detail,which provides theoretical feasibility for generating FET based on antenna array.2?Two design schemes of FET generators are proposed.Combined with the characteristics of FET,the specific design schemes of the TE FET generator and the TM FET generator are given,respectively.According to the frequency spectrum distribution of the typical microwave FET,the corresponding antenna units are designed.In addition,the finite difference time domain(FDTD)method is used to simulate effect of generating FET under different excitation signals so as determine the excitation signals of the FET generators.3?Systematic research of the proposed FET generators proposed are carried out.Firstly,based on the design schemes,the simulation structure is build in CST and simulation parameters of the array are given in detail.Then the simulation area is simplified and the simulation monitoring surface and the indicators are determined to measure the effect of generation.After that,MATLAB is used to design the excitation signal at each position,simulate and verify the FET generator proposed above.Then the results are displayed and analyzed.And the processed antenna is test.Finally,The FOM is calculated in the time domain and frequency domain to discuss the generation effect of the FET generator.