Novel Cavity Resonator-Based Microwave Plasma Spark Plug

Microwave plasma ignition can achieve stable and highly efficient lean combustion, and it represents a new avenue of research for alleviating the energy crisis and reducing exhaust emissions. In this paper, a novel spark plug is introduced, based on a coaxial microwave resonator. We simulate the new design and optimize the design of the ignition source, creating a model with a petal-shaped tip that can generate electric fields of 2.94 × 10⁷ V/m at 2.45 GHz, at an input power of 150 W. Using a ceramic dielectric, the working gas cannot permeate the resonator, improving the plug's practical value. Experimental measurements indicate that a flat microwave plasma spark plug offers good impedance matching at the ignition frequency and can achieve stable ignition at an input power of 100 W and an air pressure of 1 bar.