Design and construct a microwave plasma jet system for material processing

Summary form only given, as follows. We have designed a 2.45 GHz waveguide-based applicator to generate a microwave plasma jet (MPJ) at atmospheric pressure. The MPJ systems consist of a 1 to 6 kW magnetron power supply, a circulator, a water-cooled matched load and the applicator. The applicator includes a tuning section, which is required to reduce the reflected power, and a nozzle section. The plasma is formed by the interaction of the high electrical field, generated by the microwave power, between the waveguide aperture and the gas nozzle. A variety of gases have been used to produce the plasma including argon, helium and nitrogen. A 2 kW, 2.45 GHz MPJ, constructed using a rectangular waveguide WG9A (WR340), has been investigated. A microwave plasma jet (MPJ) has been used for material processing applications including cutting, welding, ceramic fibers and glass vitrification. The paper discusses the design parameters and the potential of the MPJ for industrial applications and how the jet can be tailored to suit different tasks, by adjusting the various parameters such as the type of the gas, the flow rate, the input power and the nozzle design.