Time Domain Spectral Element Method Analysis Of High Power Microwave Dielectric Breakdown

In recent years,wireless communication equipment has gradually been miniaturized and complicated.In order to achieve greater working bandwidth,the transmission power of equipment has been increasing.The breakdown of solid and gaseous media during high-power operation is harmful to electronic equipment.Once breakdown occurs,it is very likely to cause damage to electronic devices.Therefore,it is of great practical significance to use numerical methods to simulate the breakdown problem under the action of high-power microwaves.In this paper,the Spectral Element Time-Domain(SETD)method is chosen as the numerical method for the simulation.As a special form of Finite Element Time-Domain(FETD)method,this method combines the spectral method with the finite element method,which has both the high precision of the spectral method and the flexibility of the finite element.The main work of this paper is divided into two parts:In the first part,the nonlinear conductivity dielectric model under high-power microwave is simulated and analyzed.The nonlinear performance of the dielectric is that the conductivity is a function that changes with the electric field.The SETD method is used to derive the Maxwell's equation for coupled nonlinear conductivity,and the Fixed-point iteration method is used as the method to solve the nonlinear problem which is compared with the Leapfrog iteration method.An example is given to verify the accuracy of SETD method in analyzing this problem,then we study the problem of odd harmonics due to nonlinear phenomena.Finally,the dielectric window breakdown was simulated and analyzed.The second part analyzes the gas breakdown problem under the action of high-power microwave.In order to accurately simulate this process,based on the SETD method,Maxwell's equations and electronic fluid equations are coupled to solve the problem.First,the effect of different proportions of air and SF₆ mixed gas on the breakdown in the waveguide was studied.The results show that the breakdown time is delayed as the concentration of SF₆ increases.Then,combining nonlinear dielectric with gas breakdown,the influence of nonlinear dielectric window on background gas breakdown under high power microwave is analyzed.