Study On The Characteristics Of Low-Power Microwave Micro-plasma Based On Microstrip Split-ring Resonator

Nowadays, researches on low temperature micro-plasma have become a hot spot. With the rapid development of MEMS technique, the micro-plasma technology has included microelectronics, plasma and microwave technology. Micro-plasmas sources can be integrated into various kinds of applications, such as biological MEMS sterilization, micro-chemical analysis systems and small-scale materials processing. It has the characteristics of small size, portability and long life, etc.In order to utilize perfect micro-plasma, it is necessary to know all the processes that take place in the micro-plasma. This thesis describes the effects of magnetic field on a low-power microwave micro-plasma in air and argon based on a microstrip split-ring resonator.To start with, the theories of micro-plasma and the principle of microstrip split-ring resonator are introduced, such as operating mode and equivalent circuit model. Effects of magnetic field on micro-plasma are also discussed. And in this thesis, there are two parts to present the characterization of a low-power microwave micro-plasma in air and in atmospheric argon.For one thing, the characteristics of the microwave micro-plasma in air are analyzed with different magnetic field strength and orientation, including pressure, S-parameter, radiating spectrum, body temperature and electromagnetic compatibility. There are three magnets, whose magnetic field strength is360G,990G and2840G. The experimental results show that it’s easier for microwave micro-plasma source with magnet to discharge than without magnet, different magnet pole orientation has an impact on the micro-plasma excitation. The micro-plasma source has frequency offset respectively by using three kinds of magnets. The magnet shows no significant impacts on the spectral lines and the spectral intensity decreases as the pressure increases. The characteristics of discharge are also related with pressure, the smaller the pressure, the greater the microwave micro-plasma discharge region. The body temperature rises up and electromagnetic compatibility of the micro-plasma source is good after the micro-plasma excitation.For another, the characteristics of the microwave micro-plasma in atmospheric argon is analyzed with different magnetic field strength and orientation, including ignition power, pressure, S-parameter, radiating spectrum, contamination and body temperature. There are two magnets, whose magnetic field strength is990G and2840G. The experimental results show that ignition power decreases as the added magnetic field strength increases and different magnet pole orientation has an impact on the ignition power. The micro-plasma source has frequency offset respectively by using two kinds of magnets, but it shows no frequency offset without magnet. Compared to the microwave micro-plasma in air, the microwave micro-plasma in atmospheric argon has a wider bandwidth. The magnet shows no significant impacts on the spectral lines and the spectral intensity increases as the ignition power increases. The discharges in air and in atmospheric argon show obvious contamination to the microstrip split-ring resonator. The body temperature also rises up after the micro-plasma excitation.