A novel microwave plasma source based on inductive coupling window — Rectangular resonator

This paper introduces a novel microwave plasma source based on inductive coupling window - rectangular resonator. It is comprised of a WR430 waveguide, an inductive coupling window, a rectangular resonator, a closed cuboid quartz cavity and a sliding short-circuit plunger. This microwave plasma source can produce a large-volume stable atmospheric air microwave plasma and the plasma size is at the fewest 63 mm × (40 ~ 50) mm × 30 mm. Its linear load characteristic is studied and this study indicates that it is a linear microwave load before the plasma is produced. Its microwave reflectance ratios before and after the plasma is generated are also researched. The reflectance ratio exactly at higher power before the plasma is produced is roughly unrelated to the input microwave power. After the plasma is generated, the reflectance ratio increases with the increase in the input microwave power and the ratio at lower power is even smaller than that before the plasma is produced. The dependences of the characteristics including the emission spectral line intensity and the gas temperature of this plasma on the input microwave power are analyzed and the results show that the plasma spectral line intensity increases with the increase in the input microwave power while the gas temperature is approximately invariable.