Microwave plasma jet system development at atmospheric pressure using A 2.45 GHz GaN HEMT devices

Summary form only given. Microplasmas at atmospheric pressure have been widely used in many applications such as sterilization of medical instruments, high-precision surgery, cells treatment and deactivation of bacteria and viruses. We report a 2.45 GHz microwave-excited atmospheric-pressure plasma jet system which is consisted of a 2.45-GHz, GaN HEMT oscillator, a circulator, a three-stub tuner, and microwave plasma jet source. Advanced Design System and 3D High Frequency Structure Simulation codes are used to design oscillator and microwave plasma jet source. The operating power and frequency of this device are in 5-25 W and 2.45 GHz, respectively. The plasma jet length is estimated to be ~16 mm at 20 W. The electron temperature are measured to be Te=1.2 ~1.9 eV by using the collision radiative modes based on the argon 4p metastable lines.