Microwave-based characterization of an atmospheric pressure microwave-driven plasma source for surface treatment

A plasma source operating at atmospheric pressure by continuous or pulsed microwave at 2.45 GHz with a maximum power of 1.7kW is developed for surface treatment applications. The microwave power is coupled into a cylindrical cavity used as a process chamber. The device characteristics are studied in detail using a simple network analysis and finite integration technique simulations. Experimental results are compared with the outcome of the model. The TM01 mode in the process chamber is found to be appropriate for surface treatment. The results obtained are used to optimize and simplify the device performance and operation. It has been found that the electric field strength, responsible for plasma ignition, and the microwave power coupling into the plasma demonstrate a contradictory course-a maximum field corresponds to a minimum power in-coupled. A set of parameters representing a compromise between stable plasma ignitions and proper plasma treatment has been found.