Design and Fabrication High-Power Amplifier for Plasma Generator at Frequency of 2 MHz

This research presents the design of the solid-state RF (radio frequency) power amplifier for plasma generator. The technique to design the solid-state high-power RF amplifier at 2 MHz by using 2-way Wilkinson's power divider in which dual parallel RF power amplifier module 2 kW based on push-pull class AB biasing and 2-way Wilkinson's power combiner is designed and constructed. In part of high efficiency, S-parameter is used to define appropriate process, which is related to matching impedance for maximum power transferring. The result shows that reflection and transmission coefficient of power divider were lower -25 dB and -3.2 dB, respectively. On the other hand, the reflection and transmission coefficient of power combiner were lower -20 dB and -3.3 dB. This prototype measured the result with 50 Ω dummy load that is demonstrated by 4 kW output power, 76% efficiency and 62 dB power gain. To achieve high efficiency, we used variable capacitor to compensate parallel with conventional BALUN (balance to unbalance) transformer surrounded by ferrite core.