Dual-Frequency Microwave Plasma Source Based on Microwave Coaxial Transmission Line

Abstract

A dual-frequency plasma source has many advantages in applications. In this paper, a dual-frequency microwave plasma source is presented. This microwave plasma source is based on a coaxial transmission line without the resonator, and it can be operated in a wide band frequency region. Two microwaves are inputted from two ports into the plasma reactor: one is used firstly to excite the plasma and the other one is used to adjust plasma characteristics. Based on the COMSOL Multiphysics simulation, the experiment is carried out. In the experimental investigation, the plasma electron density and electron temperature can be controlled, respectively, by feeding in different frequencies from the second port, causing the particles at different energy levels to present different frequencies. This exploratory research improves the operation frequency of dual-frequency microwave plasma sources from RF to microwave.

A Low-Reflection Tuning Strategy for Three-Stub Waveguides

“…The input impedance in Figure 2b is (2) where Xc is impedance of equivalent capacitance. In order to simplify the analysis, the input impedance is converted to the input admittance, (3) where C is equivalent capacitance value of the stub and ω is the angular frequency.…”

“…Microwave energy has been widely used in many aspects of industrial applications, such as microwave heating, microwave plasma, microwave sterilization, microwave medical treatment, and microwave chemistry [1][2][3][4][5][6]. In high-power microwave applications [7][8][9], a three-stub waveguide is often adopted between the source and the load to perform impedance matching and to reduce reflection.…”

The Applications of Plasma Techniques II

“…Chi Chen et al in [1] presented a dual-frequency microwave plasma source based on microwave coaxial transmission line, and 915 and 2450 MHz microwaves were used in this study. Two waves were delivered from two ports into the plasma reactor.…”