The tapered waveguide as a microwave plasma excitation structure is widely used in the industrial field. However, it needs high input microwave power to ignite and sustain plasma because its electric field is not sufficiently focused in the discharge area. In order to solve this problem, this paper proposes a novel microwave plasma source based on a ridged waveguide. The structure of the proposed microwave plasma source is optimized to focus the electric field in the discharge region by electromagnetic calculations before the plasma excitation. Then, the equivalent circuit model is used to analyze the impedance matching characteristics of the novel device after the plasma excitation. In order to validate this device, a microwave plasma system is built to measure the plasma exciting power and sustaining power in both air and argon at atmospheric pressure. The simulation and experiment are carried out in both tapered waveguide and the proposed device. Simulation results show the electric field of the ridged waveguide is 1.9 times of that of the tapered waveguide when the input power is 1500 W. Moreover, in the experiments, the exciting power and sustaining power of the air and argon plasma in the novel device are lower than those of the tapered waveguide at different gas flow rates.
2. Moon, S. Y., J. W. Han, and W. Choe, "Feasibility study of material surface treatment using an atmospheric large-area glow plasma," J. Thin Solid Films, Vol. 506, 355-359, May 2006.
doi:10.1016/j.tsf.2005.08.081
3. Laroussi, M., "Sterilization of contaminated matter with an atmospheric pressure plasma," IEEE Transactions on Plasma Science, Vol. 24, No. 3, 1188-1191, 2002.
doi:10.1109/27.533129
4. Hiro, K., Plasma Electronic Engineering, OHM & Science Press, Beijing, China, 2002.
5. Moon, S. Y., et al., "Characteristics of an atmospheric microwave-induced plasma generated in ambient air by an argon discharge excited in an open-ended dielectric discharge tube," J. Physics of Plasmas, Vol. 9, No. 9, 4045-4051, 2002.
doi:10.1063/1.1495872
6. Zhao, Q., S. Z. Liu, and H. H. Tong, Plasma Technology and Its Applications, National Defence Industry Press, Beijing, 2009.
7. Zheng, Z., et al., "Study on Argon plasma jets at atmospheric pressure in ambient air excited by surface waves," IEEE Transactions on Plasma Science, Vol. 24, No. 4, 911-916, 2014.
doi:10.1109/TPS.2013.2295837
8. Levko, D., A. Sharma, and L. L. Raja, "Plasmas generated in bubbles immersed in liquids: Direct current streamers versus microwave plasma," Journal of Physics D: Applied Physics, Vol. 49, No. 28, 285205, 2016.
doi:10.1088/0022-3727/49/28/285205
9. Chapman, A., et al., "Plasma generation by dielectric resonator arrays," Plasma Sources Science & Technology, 2016.
10. Yang, Y., W. Hua, and S. Y. Guo, "Numerical study on microwave-sustained argon discharge under atmospheric pressure," Physics of Plasmas, Vol. 21, No. 4, 7-963, 2014.
doi:10.1063/1.4872000
11. Baeva, M., et al., "Pulsed microwave discharge at atmospheric pressure for NOx decomposition," Plasma Sources Science & Technology, 2002.
12. Kim, H. J., J. J. Choi, and J. M. Hong, "Uniform long-slit microwave plasma generation from a longitudinal-section electric mode coupling," IEEE Transactions on Plasma Science, Vol. 34, No. 4, 1576-1578, 2006.
doi:10.1109/TPS.2006.878995
13. Kabouzi, Y., D. B. Graves, E. Castanos-Martinez, and M. Moisan, "Modeling of atmospheric- pressure plasma columns sustained by surface waves," Phys. Rev. E, Vol. 75, 016402, 2007.
doi:10.1103/PhysRevE.75.016402
14. Chaichumporn, C., et al., "Design and construction of 2.45 GHz microwave plasma source at atmospheric pressure," Procedia Engineering, Vol. 8, 94-100, 2011.
doi:10.1016/j.proeng.2011.03.018
15. Kuo, S. P., et al., "Characteristics of an arc-seeded microwave plasma torch," IEEE Transactions on Plasma Science, Vol. 32, No. 4, 1734-1741, 2015.
doi:10.1109/TPS.2004.832517
16. Zhang, D., et al., "Design of novel dual-port tapered waveguide plasma apparatus by numerical analysis," Physics of Plasmas, Vol. 23, No. 7, 2016.
17. Abdel-Fattah, E., H. Shindo, R. Sabry, and A. El Kotp, "Experimental and numerical investigations of line-shaped microwave argon plasma source," Progress In Electromagnetics Research M, Vol. 43, 183-192, 2015.
doi:10.2528/PIERM15071004
18. Moisan, M., et al., "A waveguide-based launcher to sustain long plasma columns through the propagation of an electromagnetic surface wave," IEEE Transactions on Plasma Science, Vol. 12, No. 3, 203-214, 1984.
doi:10.1109/TPS.1984.4316320
19. Iio, S., et al., "Influence of gas flow on argon microwave plasma jet at atmospheric pressure," Surface & Coatings Technology, Vol. 206, No. 6, 1449-1453, 2011.
doi:10.1016/j.surfcoat.2011.09.013
20. Zhang, W., et al., "Numerical investigation of the gas ow effects on surface wave propagation and discharge properties in a microwave plasma torch," IEEE Transactions on Plasma Science, Vol. 47, No. 1, 271-277, 2019.
doi:10.1109/TPS.2018.2882637
21. Pozar, A. D. M., Microwave Engineering, Publishing House of Electronics Industry, Beijing, 2019.
22. Fleisch, T., et al., "Designing an efficient microwave-plasma source, independent of operating conditions, at atmospheric pressure," Plasma Sources Science & Technology, Vol. 16, No. 1, 173, 2006.
doi:10.1088/0963-0252/16/1/022
23. Miotk, R. and M. Jasinski, "Investigation of the electrodynamic characteristics of 2.45 GHz microwave plasma sheet source," IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 1-4, 2019.
24. Miotk, R., M. Jasinski, and J. Mizeraczyk, "Improvement of energy transfer in a cavity-type 915- MHz microwave plasma source," IEEE Transactions on Microwave Theory and Techniques, Vol. 66, No. 2, 711-716, 2018.
doi:10.1109/TMTT.2017.2778068
25. Kim, J. D., et al., "Impedance measurement system for a microwave-induced plasma," Journal of the Korean Physical Society, Vol. 60, No. 6, 907-911, 2012.
doi:10.3938/jkps.60.907
26. Mitsugi, F., et al., "Gas flow dependence on dynamic behavior of serpentine plasma in gliding arc discharge system," IEEE Transactions on Plasma Science, Vol. 42, No. 12, 3681-3686, 2014.
doi:10.1109/TPS.2014.2363653
27. Gurel, C. S. and E. Oncu, "Interaction of electromagnetic wave and plasma slab with partially linear and sinu-soidal electron density profile," Progress In Electromagnetics Research Letters, Vol. 12, 171-181, 2009.
doi:10.2528/PIERL09061707
28. Miotk, R., M. Jasinski, and J. Mizeraczyk, "Equivalent circuit of a coaxial-line-based nozzleless microwave 915MHz plasma source," IOP Conference, 113, 2016.
29. Miotk, R., "Equivalent circuit of a microwave plasma source for hydrogen production from liquid substances," Przeglad Elektrotechniczny, Vol. 1, No. 8, 31-34, 2016.
doi:10.15199/48.2016.08.08
30. Nowakowska, H., M. Jasinski, and J. Mizeraczyk, "Modelling of discharge in a high-flow microwave plasma source (MPS)," European Physical Journal D, Vol. 67, No. 7, 1-8, 2013.
doi:10.1140/epjd/e2013-30514-y