Study On RF Breakdown In Bend Waveguide

As an important transmission component in microwave devices,waveguide elbow is mainly used in high-power microwave,millimeter wave transmission systems and other related fields.Its main function is to achieve matching with microwave devices in different caliber directions,and its performance affects the efficient transmission of high-power microwave.Therefore,the research on the radio frequency breakdown effect of waveguide elbow is of great significance.This paper explores the radio frequency breakdown effect of the 90°waveguide elbow.The main work and contributions are as follows:1. Aiming at the particle simulation software CST particle studio,comparing with the RF breakdown phenomenon of rectangular waveguide structure and analyzing the rectangular waveguide electronic resonance dynamics and the susceptibility,it is concluded that about RF breakdown simulation in the CST particle studio under high power and high frequency.There are shortcomings,combing with CST software and self-written RF breakdown simulation program is for subsequent simulations.This method is used to randomly processes the parameters such as the emission energy,emission angle and phase of the secondary electrons,the electromagnetic field distribution of the waveguide elbow simulated by the CST microwave studio is loaded into the calculation space,and combing with the fourth-order Runge Kuta method and Vaughan's The secondary electron emission model tracks changes in electron trajectory,average electron energy,and number of electrons.2. A Ku waveguide 90°rectangular waveguide elbow model was established for RF breakdown simulations.By comparing with the changes in the RF breakdown effect of the E-plane bending and the H-plane bending with the power transmission value and rotation radius,the trajectory and breakdown position of the electrons were analyzed The effect of ponderomotive force on radio frequenly breakdown is studied by the non-uniform distribution of magnetic field force and electromagnetic field.It shows that when breakdown effect occurs.The breakdown threshold of the E-plane bending rectangular waveguide elbow is smaller than that of the H-plane curved bending waveguide elbow.3. The TE₁₁ mode circular waveguide elbow of X-band 90°constant curvature is simulated for the process of linear change of microwave power to GW level during the RF breakdown process of 90°constant curvature circular waveguide elbow under horizontal polarization vertical polarization.By tracking the trajectory and velocity of electrons,comparing the changes in parameters such as the number of secondary electrons,average energy,average yield,and the number of collisions at the statistical boundary,the RF breakdown phenomenon of different polarization modes in the same waveguide bending elbow is analyzed.Under the vertical polarization of the TE₁₁mode of a 90°circular waveguide elbow,the area where a large number of electrons converge is the curved wall of the waveguide?weak electric field area?,namely,the location of RF breakdown.However,under the horizontal polarization of the TE₁₁mode of a 90°circular waveguide,the area where RF breakdown occurs is the upper and lower polar plates of the waveguide and the boundary of the inner curved wall?weak electric field area?.but,under the two polarization modes,the breakdown threshold of horizontal polarization is greater than that of vertical polarization,which is consistent with the previous high-power experimental results.This study provides available value for the design and selection of waveguide elbows in engineering reference.