Design of a plasma generator based on E power amplifier and impedance matching

The paper presents the design key issues for a plasma generation method. A Class E Power Amplifier is used to generate plasma at 13.56MHz with a variable load implemented with an air coil and a variable capacitor. Class E amplifier represents a mean of high efficiency power amplification. Ideal amplifiers reach 100% efficiency and by proper filtering and tuning even the real circuit efficiency can be only 5% lower. By measuring the input impedance of the matching network the resistance, the voltage and the power of the plasma torch can be estimated. In order to do that, two matching networks were designed; the first one is partially compensated and the second is completely compensated. The problems that can appear at a capacitive tuning in air and Argon atmosphere are also presented. Finally, the steps needed to design the plasma generator with class E power amplifier and air coils are described.