Engineering Implementation Technology Of Waveguide Plasma Limiter

High power microwave can enter the electronic equipment through various coupling channels,the most serious of which is the receiver system of radio frequency front end,which will cause interference and damage in the electronic equipment,so the protection of high power microwave is particularly important.Based on the principle of waveguide plasma limiter,the structure of waveguide plasma limiter is designed by using the transmission characteristics of electromagnetic wave in waveguide resonator.Two methods are studied to accelerate the formation time of plasma,and the factors affecting the isolation of ideal multi-layer plasma structure are analyzed.The main contents of this paper are as follows:1.High-power microwave destroys electronic equipment through energy coupling.Firstly,the components that are vulnerable to high-power microwave damage in waveguide transmission RF front-end link are analyzed.The power of high-power microwave entering radar receiver is calculated,and the damage of high-power microwave to receiver is analyzed numerically.It shows the necessity of using waveguide plasma limiter for protection.2.According to the transmission characteristics of electromagnetic wave in the waveguide resonator,the resonant window and the resonant gap of the waveguide plasma limiter are designed.The formulas of breakdown field strength and plasma formation time of inert gas at low and high pressure are derived.Taking X-band waveguide as an example,the effects of parameters on breakdown field strength and plasma formation time are analyzed by matlab simulation.The results show that the breakdown field strength of Xe time limiter filled with gas pressure of 3 Torr is the lowest and the plasma formation time is the shortest.3.Two methods of accelerating plasma formation time in waveguide plasma limiter are studied.One is the external DC power supply method.According to the typical discharge volt-ampere characteristic curve and the current magnitude and equivalent electron concentration between electrodes in glow discharge area,the relationship between plasma formation time and electron concentration is analyzed,and the plasma formation time under typical electron concentration is simulated.Due to the extra noise and large volume of the external power supply,another method of using radioactive tritium igniter pole to form a certain electronic concentration by using beta radiation of tritium on the igniter pole was studied.According to the relationship between the amplitude of wave tip and the current of igniter in the double igniter experiment,the electron concentration magnitude of tritium target can be calculated,and the specific formation time of plasma can be obtained by using the relationship curve between the formation time of plasma and the electron concentration.4.According to the propagation characteristics of electromagnetic wave in uniform plasma and the theory of electron micro-motion,the formulas for calculating the reflection power and absorption power of plasma to electromagnetic wave are analyzed,and the relationship between the isolation of waveguide plasma limiter and plasma concentration is simulated and analyzed.Aiming at the problem of insufficient protection of high power microwave peak power and non-ideal uniform distribution of plasma in practice,a single layer dielectric plasma and a multi-layer dielectric plasma protection model are constructed.The isolation degree of single layer dielectric plasma structure and multi-layer dielectric plasma structure are simulated and analyzed,and the isolation degree,plasma concentration and plasma concentration are obtained.The relationship between body thickness proves that it has good protection for the later circuit.