A Large-Volume Stable Atmospheric Air Microwave Plasma Based on Inductive Coupling Window—Rectangular Resonator

This paper introduces a novel microwave plasma source based on inductive coupling window—rectangular resonator. It consists 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 smallest 63 mm
$\times\,$
(40–50) mm
$\times\,$
30 mm. The microwave reflectance ratio of the microwave plasma source exactly at higher power is roughly unrelated to the input microwave power before the plasma is produced. 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 gas temperature of the atmospheric air microwave plasma is approximately changeless with the input microwave power. The atmospheric air microwave plasma cuts off the microwave with the frequency of 2450 MHz.