Atmospheric Plasma Source – First Pilot Series

Plasmas at atmospheric pressure open up new applications in medical and industrial fields and are presently the subject of various research activities. At FBH, a new microwave plasma source for operation at atmospheric pressure was developed together with Aurion Anlagentechnik. The source contains an integrated microwave oscillator, based on a GaN power transistor fabricated at FBH. The integrated concept allows cost-efficient manufacturing, furthermore a safe operation without high voltages is possible.

This is presently the only plasma source worldwide which uses a GaN transistor for power generation. The supply voltage is only 24 V and the oscillator delivers a power of approximately 10 W to the plasma. Inside the source, the microplasma achieves a temperature of more than 1200°C which is significantly higher than for example at barrier discharges and enables interesting plasma chemical applications. Nevertheless, the temperature at the treatment location outside the source is lower than 60°C.

Key to success was the development of new microwave measurement methods to characterize the nonlinear and dynamic impedance behavior of the plasma load. This allowed an efficient circuit design of the power oscillator.

Subsequent to the optimization of several prototypes, a first pilot series has been manufactured. After assembly and electrical set up at FBH, the process performance of the sources was analyzed quantitatively by Aurion. High activation capabilities and good reproducibility within the different samples were found. Presently, samples are provided to customers for tests and development of applications.

FBH research: 24.06.2010