Improvement of Energy Transfer in a Cavity-Type 915-MHz Microwave Plasma Source

An improvement in the energy transfer in a cavitytype microwave plasma source (MPS) operated at 915 MHz by a better design of the device, capable of ensuring a high microwave power coupling from the supply line to the sustained plasma was a goal of this paper. Our approach was twofold. First, numerical simulations of an electromagnetic field distribution inside a typical cavity-type MPS were carried out. The standard model of homogeneous plasma generated by the MPS and the two-port method was combined. This enabled estimating the concentration ne and collisions frequency ν of electrons in the plasma. Based on these data, a more energy efficient MPS could be designed. Second, to verify the numerical prediction, a modified version of the MPS was built and the improvement in the MPS energy efficiency was proved experimentally.