Modeling of Argon Plasma Excited by Microwave at Atmospheric Pressure in Ridged Waveguide

As a microwave plasma excitation structure, the tapered waveguide is mostly used in some industrial applications. A novel ridged waveguide is proposed in this paper. The fluid approximation method is applied here to simulate the excitation of argon plasma within 1 s at atmospheric pressure. Some physical parameters, such as the electron density, electron temperature, gas temperature, and scattering parameter S11, are obtained. When the input power is set to 1500 W, and the steady state is achieved, the electron density reaches 3.05×1020m-3, the electron temperature gets to 282 15 K, and the gas temperature is 5590 K. Remarkably, at the same power, the energy coupling efficiency from microwave to plasma is 17.3% higher than that in the tapered waveguide, and the electron density and gas temperature also increase by 4.5 × 1019m-3and 346 K, respectively.