A Power-Efficient Microwave Microplasma Jet Utilizing an SIW Evanescent-Mode Cavity Resonator

This paper introduces a novel 2.45 GHz microplasma jet implemented over substrate-integrated waveguide (SIW) technology. The proposed plasma jet is realized by exploiting an evanescent-mode (EVA) cavity resonator built using two separate PCB boards stacked over each other to introduce a critical gap between the two substrates around the top-center position. This allows for realizing a concentrated |E|-field in the gap for plasma formation. A capillary tube is passed right through the middle of the structure to pump helium through the critical gap area. After gas breakdown owing to the strong |E|-field in the gap with > 2.7 W input power, the gas flow pushes the plasma plume out, which is up to 3-mm long with 7 slpm gas flow rate. The proposed technology is an excellent option for many applications owing to its high efficiency, planar profile, and compatibility with PCB fabrication.