Microwave-excited atmospheric-pressure plasma jets using a microstrip line

Abstract

We report a 2.45GHz microwave-excited atmospheric-pressure plasma jet (MW-APPJ) device using a microstrip line for materials processing. A three-dimensional simulation based on the finite difference time domain method revealed that the configuration of the MW-APPJ device results in a strong concentration of electric fields at the gas nozzle. Argon plasmas were generated at the nozzle and were blown into ambient air with the maximum length of 5mm at a microwave power of 40W. The rotational temperatures of molecular nitrogen in the downstream of the plasma jets, measured by optical emission spectroscopy, were 1720to900K for gas flow rates from 0.5to3.5l∕min, indicating that the jets were nonthermal plasmas. This MW-APPJ device will provide a large-area APPJ for materials processing depending on the configuration of the nozzle array and microstrip lines.