The Optimization Of Microwave Resonat Probe In High Pressure

The quality factor of the microwave resonant probe is effectively improved through simulation and experiment in this paper.In simulation,the geometrical structures of the microwave resonant probe and the coupling coil are optimized by its influence to the storage energy and radiation loss of a probe.The position between the probe and its coupling coil is changed in order to enhance the coupling,Then,the optimized microwave resonant probe is used to diagnose the high pressure plasma jet.Firstly,the geometrical structure of microwave resonant probe is optimized.The quality factor of microwave resonant probe is calculated when changing its length,width and the diameter of metal wire.As for coupling coil,its radius and the diameter of the metal wire are changed,and then quality factor of probe is also calculated.Secondly,the position of resonant probe and coupling coil is changed from two directions: horizontal and vertical.The coupling effect at different positions is analyzed with the quality factor.During optimization,the method of adding the shield to decrease the radiation of coupling coil is proposed.And the method is proved correctly and feasibly by simulation and experiment.Finally,the optimized microwave resonant probe is used to diagnose the high pressure plasma jet.The diagnosis results are showed that the larger discharge power or gas flow rate is,the larger the FWHM?or quality factor is smaller?of the measured reflection resonance spectrum is.It indicates that the more electrons are generated in the jet region,the more energy is consumed around the probe.The electron density of the jet region with discharge power at 30 W,40W,50 W and 60 W is estimated by formula to be 5.157×10¹⁵m^-31.143×10¹⁷m^-3.