Characteristics of surface discharging and gas desorption of PTFE due to electron beam irradiation

PTFE (Polytetrafluoroethylene) with a low dielectric constant and less microwave loss is widely applied in dielectric microstrip antenna and has a significant prospect on low-cost miniaturization satellite cluster. In contrast, the surface discharging induced by space electron beam irradiation degrade antenna radiation efficiency and generate pulse interference signal, which comes to be the critical challenge for employing in orbit. In this paper, we use an experiment and simulation combined method for avoiding surface discharging current path to figure out the charging states and gas desorption phenomenon. The charging state numerical simulation calculates secondary electron emission and deposited electron-hole pair distribution with the Monte Carlo simulation. In addition, we investigate the surface gas desorption, chemical state, as well as morphology of PTFE film under different irradiation situations in situ. We find that the electron irradiation with a higher energy can result in a more frequent discharging, meanwhile, coming with a lower surface discharging potential yet. In spite of a less incident current, the gas desorption rate under the satisfied discharging irradiation presents to be larger than the none discharging irradiation situation. Under the 20 keV E-beam irradiation, the F1s spectrum translates more remarkably, and the C1s spectrum presents a greater promotion on breakage of C–F bond. The presented results and numerical simulation method in this study can offer a comprehensive insight into researches and developments on dielectric microstrip antenna in space.