Experimental Study on the Effects of Waveguide and Antenna Coupling on ECR Discharge

For an electron cyclotron resonance (ECR) plasma source, a critical challenge in industrial applications lies in enhancing microwave ionization efficiency. Consequently, optimizing microwave coupling mechanisms is essential, as it directly influences plasma generation and overall system performance. In this study, two distinct microwave coupling methods, waveguide coupling and antenna coupling, were designed, and further verification was conducted through experimental test data. Acomparative test was conducted on the electron density and uniformity of the two different ECR plasma coupling discharge modes. The measurement tool employs the highly mature Langmuir probe array to detect the electron density in different spatial areas. The electron density and its spatial distribution were measured under varying discharge conditions. Additionally, the advantages and limitations of each coupling mode were systematically evaluated and discussed. The experimental results indicate that the electron density in the plasma generated via direct waveguide coupling was higher than that achieved through antenna coupling. However, the plasma generated using the microwave antenna coupling system exhibits better overall density uniformity compared to the direct waveguide feeding system. This comparative analysis of the two discharge modes offers valuable data for optimizing ECR plasma discharge configurations in future applications.