Suppressing the Multipactor in Microwave Devices by Introducing the Dielectric Material

This study proposes a method for suppressing the multipactor effect in high-power microwave devices for spacecraft applications by integrating dielectric materials. Electromagnetic fields are numerically analyzed using the CST Microwave Studio, while multipactor thresholds are accurately predicted via an in-house developed 3-D particle-in-cell (PIC) simulation code. A systematic investigation is conducted to examine how the geometric parameters and material properties of dielectric influence multipactor. Simulation results show that when the dielectric width matches that of a parallel-plate or rectangular waveguide, increasing both the thickness and relative permittivity enhances the amplitude of the radio frequency (RF) electric field, accompanied by a decrease in the multipactor threshold. Conversely, when the dielectric width is smaller than the waveguide, the RF electric field amplitude decreases, leading to an increase in the multipactor threshold. Notably, partially filled dielectric can reduce the RF electric field amplitude by up to 90%, and improve the threshold by as much as 40 times compared to unfilled dielectric. These findings provide critical design insights for high-power microwave components in space applications.