介绍了一台低成本的常压微波等离子体炬设备，给出了该设备构造及喷嘴的设计思路，分析了各种气体的非磁化微波等离子体的击穿电场强度，数值求解了设备中矩形TE103谐振腔中的电磁场分布，应用高频电磁场模拟分析软件HFSS优化了喷嘴在波导中的具体位置,并对优化后喷嘴周围的电场分布进行了模拟。模拟结果表明：微波输入有效功率为500 W，喷嘴伸出矩形波导1 mm时，喷嘴尖端处的电场强度在1.2×106 V·m-1以上，远大于氩气的击穿电场强度，更易于等离子体炬的激发。实验结果证明了模拟结果的正确性和装置的有效性。

The advantages of the atmospheric pressure microwave plasma jet(MPJ) over the previous and conventional methods make it a potential system for certain industrial material processes. This paper presents the design of this MPJ, the theoretical consideration of microwave ignition, the optimization of the nozzle and the simulation results, including the distributions of the electric field inside the TE103 rectangular cavity as well as the tip of the nozzle. The results show that when the nozzle length passed through the hole on the cavity wall is 1 mm and the power is 500 W, the electric field strength at the position of tip nozzle is above 1.2×106 V·m-1 which is higher than the breakdown field strength of the working gases. Both simulation result and the observations of the MPJ are in good agreement.