Parametric Optimization of a Birdcage Resonator for Low-pressure Plasma Excitation

This paper deals with an analysis of the electric field inside birdcage resonators and discusses the geometric optimization of such resonators, emphasizing the electrical parameters. Firstly, we chose several different values of capacitors. For each capacitor value, parametric optimization was used to find the right geometry, for which the fundamental resonance mode lies at the frequency of interest (433 MHz). The numerical analysis results were employed as the basis for fabricating birdcage resonator prototypes. The prototypes’ parameters were measured using a vector network analyzer. Thus, we obtained a series of resonators working at similar frequencies (the deviation between the measured and the simulated values in dependence on the coil geometry is evaluated). The measured parameters and the simulated field distributions are compared and discussed with regard to the electrical properties of the resonators, electric field intensity, and homogeneity. The possible applications (such as an electric propulsion engine) are discussed.