Numerical analysis of metal-cylinder-based microwave plasma module

Abstract

We present optimization of energy transfer in the waveguide-supplied metal-cylinder-based microwave plasma module with an inner cylindrical quartz tube. The construction of microwave plasma module is based on a WR 340 waveguide standard. Presented microwave plasma module operates at atmospheric pressure and frequency of 2.45 GHz. There is a reduced height section waveguide in microwave plasma module which provides local increase of the electric field in the plasma region. Microwave plasma module is terminated with a movable plunger which plays the role of the tuning element. Tuning characteristics of microwave plasma module are defined as the dependence of the PR/PI on the position ls of the movable plunger, where PR and PI are the microwave power reflected and power incident, respectively. The powers PR and PI are measured in the input plane of microwave plasma module. The purpose of the presented optimization is to achieve PR lower than 5% of PI in widest range of position of movable plunger ls. We used Comsol Multiphysics software to make numerical analysis which allows to optimize the parameters of microwave plasma module. Results of numerical analysis show that PR/PI is lower than 0.05 in a wide range of movable plunger position ls.