大功率铁磁性微波部件微放电演变机理与抑制

Multipactor evolution and suppression in high-power ferromagnetic components

铁氧体环行器是承载航天器微波系统大功率的关键器件,其大功率微放电效应是影响航天器在轨安全、可靠运行的瓶颈问题。从影响微放电效应的关键因素--二次电子发射特性出发,提出铁磁性微波部件微放电效应物理演变模型,揭示了铁磁性微波部件内部初始自由电子与二次电子运动的空间规律;通过改变铁磁性微波部件表面二次电子发射特性,揭示了铁磁性微波部件抗微放电优化设计的物理原理。在S频段铁氧体环行器中验证了基于表面二次电子发射特性的微放电效应抑制,将器件的微放电阈值从380 W提高至3400 W以上,提升效率大于900%。

Ferrite circulators are key components in the high-power microwave systems for the satellite payload application.Multipactor,which is prone to occur in the high-power vacuum system,is still a bottleneck problem for the on-orbit reliable system operation.The physical evolution model of multipactor in ferromagnetic components is proposed based on the secondary electron emission(SEE)properties.Using the model,the evolution laws of the initial electrons and multipacting electrons in practical components with micro-pore arrays are revealed.Furthermore,a novel anti-multipactor design method is proposed through controlling the surface SEE of the ferromagnetic material.A group of S-band circulators were designed and fabricated for the validation of the theory and design method.Calculation results and measurement data demonstrate that multipactor discharge has been suppressed successfully through lowering the surface SEE on the ferrite plates.Multipactor threshold power of the traditional circulator has been improved from 380 W to more than 3400 W using the optimized micro-pore structures,and the suppression efficiency is increased by more than 900%.