| In recent years,due to the urgent demand of terahertz sources in the fields of communication,security screening imaging and biomedical diagnostics,traveling wave tube,as an important vacuum electron terahertz source,has aroused wide attention of domestic and foreign scholars.At the same time,a large number of new-type terahertz TWT is emerging to break the limit of electric vacuum device size.The process of wave-beam interaction is the core of traveling wave tube,and is the key to the performance design of traveling wave tube.Therefore,it is of great significance to develop the common simulation software of wave-beam interaction to deal with the simulation design of these new terahertz TWT.NRL has developed a common code TESLA-TWT for wave-beam interaction in traveling wave tubes.Penwe PhD puts forward the theory of general beam interaction,based on the Christine model.And this paper will further studies the theory of general wave interaction of TWT and the related software implementation technology.Based on the visual Studio 2010 platform,a general theory simulation program is developed under the framework of the electromagnetic simulation set MTSS developed by this research group.Using MTSS's high frequency solver HFCS,the high-frequency characteristic parameters and high-frequency electric field distributions of the slow wave structure can be simulated quickly,and the parameters are used as the input parameters of the general theory program,and the whole wave interaction simulation of any slow wave structure can be completed according to the simulation process of the general theory program.In addition,in order to simulate the complex hopping/gradual slow wave structure in the real traveling wave tube,a high frequency field distribution matching method is proposed in this paper.For high frequency jump structure,it is necessary to simulate the single period structure corresponding to the structure before and after the jump,and to deal with high-frequency field matching when the high frequency field is distributed,so that the high frequency field distribution power of the whole slow wave structure is conserved and the phase is continuous.For the gradual change structure,the method of multiple-segment hopping can be used to deal with it.In order to verify the generality and accuracy of the general theory program,in this paper,a general theory program is used to simulate the wave-beam interaction between helical and coupled-cavity TWT,and the saturation output power in the range of the band is compared with the MTSS simulation results,and the results show that the results are in agreement.In addition,a terahertz wave band folded waveguide TWT and a terahertz new comb-type traveling wave tube(DCW TWT)are also simulated,and the output power at the center frequency is compared with that of CST.There are still some differences between the general theory program and the CST simulation results,because the effect of back wave and reflection is not considered in the model,and the effect of the return wave is considered in the future General Theory program to improve the accuracy of the calculation. |
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