Efficient conversion of the microwave energy into an atmospheric-pressure argon plasma in a microwave plasma sheet source (MPSS) operating at 2.45GHz in ambient air is the subject of this work. The MPSSs, capable of providing an atmospheric pressure plasma in the shape of a narrow sheet are an innovative technology for variety of surface treatments with no impact on the environment. The existing designs of the MPSS exhibit unsatisfactory efficiency of the conversion of microwave energy produced by the microwave source into the microwave plasma (about 80%), which hinders implementation of the MPSSs in the industry. In this paper, after an analytical approach based on the equivalent electrical circuit method we proposed an optimization of the design of MPSS in terms of the microwave energy conversion efficiency. The MPSS design improvement consisted in reducing the electrical impedance in the input plane of the MPSS by introducing a capacitive diaphragm into the MPSS transmission line, which compensated the inductive character of the plasma sheet. The experimental measurement of the electrodynamic characteristics of the MPSS with diaphragm showed that using the diaphragm significantly decreased the microwave power losses due to the microwave reflection from about (20–30)% to a level of several percent. This substantially increased the MPSS energy conversion efficiency up to about 97%, 93% and 87% for incident powers P _I of 500W, 750W and 1000W, respectively. The electrodynamic characteristics of the MPSS appeared a very convenient tool for determining the conditions of maximum efficiency of conversion of the microwave energy into the microwave plasma. The electrodynamic characteristics were measured at argon flow rate of 20 Nl min⁻¹. The analysis of the calculated input impedances of the MPSSs with and without diaphragm, based on the equivalent electrical circuits of both MPSSs confirmed that the change of the character of the input reactance of the MPSS from inductive to capacitive after introducing the diaphragm is the cause of the increase in the MPSS energy conversion efficiency. The MPSSs having the energy conversion efficiency such high as presented in this paper appears to be attractive innovative technology for economic use in industrial applications.

在环境空气中以 2.45GHz 运行的微波等离子体片源 (MPSS) 中，微波能量有效转换为大气压氩等离子体是这项工作的主题。MPSS 能够提供窄片形状的大气压等离子体，是一种创新技术，可用于各种表面处理，不会对环境产生影响。MPSS的现有设计将微波源产生的微波能量转化为微波等离子体的效率不理想（约80%），这阻碍了MPSS在工业中的实施。在本文中，在基于等效电路法的分析方法之后，我们提出了在微波能量转换效率方面对 MPSS 设计的优化。MPSS 设计改进包括通过在 MPSS 传输线中引入电容隔膜来降低 MPSS 输入平面的电阻抗，从而补偿等离子片的电感特性。对带隔膜的 MPSS 电动力学特性的实验测量表明，使用隔膜显着降低了由于微波反射引起的微波功率损失，从约 (20-30)% 降低到几个百分点。这大大提高了 MPSS 能量转换效率高达约 97%、93% 和 87% 的入射功率 对带隔膜的 MPSS 电动力学特性的实验测量表明，使用隔膜显着降低了由于微波反射引起的微波功率损失，从约 (20-30)% 降低到几个百分点。这大大提高了 MPSS 能量转换效率高达约 97%、93% 和 87% 的入射功率 对带隔膜的 MPSS 电动力学特性的实验测量表明，使用隔膜显着降低了由于微波反射引起的微波功率损失，从约 (20-30)% 降低到几个百分点。这大大提高了 MPSS 能量转换效率高达约 97%、93% 和 87% 的入射功率P _我分别500W，750W和1000W的。MPSS 的电动力学特性似乎是一种非常方便的工具，用于确定微波能量转化为微波等离子体的最大效率条件。在 20 Nl min ^{-1 的}氩气流速下测量电动特性. 基于两种 MPSS 的等效电路，对带和不带隔膜的 MPSS 计算输入阻抗的分析证实，引入隔膜后 MPSS 的输入电抗特性从感性到容性的变化是导致MPSS 能量转换效率的提高。具有如本文所述的高能量转换效率的 MPSS 似乎是在工业应用中经济使用的有吸引力的创新技术。