Study on Time-domain Characteristics of Waveguide Plasma Limiter

To effectively avoid damage to sensitive microwave devices caused by high-power microwaves, this paper selects argon gas as the filling gas and proposes a waveguide plasma limiter model. This model can seal low-gas-pressure inert gases and increase local field strength. Under high power, it can respond quickly and has a high degree of isolation, but when the high power ends, it can recover to an unlimited state. Based on the finite element method, a plasma fluid model is used for numerical simulation to obtain the time-domain evolution characteristics of electron density, electric field, etc. The numerical results indicate that at the beginning, the gas around the discharge electrode in the limiter is strongly ionized and forms a short road surface, reflecting microwave pulses, and the electron concentration at the subsequent electrode decreases; As time goes on, due to the formation of a short road surface at the front electrode, the electric field at the resonant window gradually reaches its maximum, and the electron density at the resonant window also increases rapidly. The high-density plasma region gradually moves towards the incident end, ultimately achieving stability. Within a certain electron density range, the initial electron density does not affect whether a plasma is formed, but only the length of time it takes to form a plasma. The research in this paper can provide a theoretical basis for the design and optimization of microwave plasma limiters.