Effects of electrode configuration and orientation on electromagnetic field distribution and temperature evolution in radio frequency systems

Abstract

Electrode (potential applied electrode and ground electrodes) configuration and their orientations affect the electromagnetic field distribution within the radio frequency (RF) systems and temperature evolution inside the processed samples. Parallel flat plate and staggered through field or rod electrode systems are common electrode designs. Therefore, the objective of this study was to compare the effect of electrode configuration and orientation on electromagnetic field distribution in various RF systems and resulting temperature evolution.

For this purpose, a mathematical model was first developed and validated with the experimental data obtained from three different RF systems (two staggered through field electrode configuration systems and a parallel plate electrode configuration system). Potential values of 2300 to 14,000 V through the charged electrode were obtained at the electrode gaps of 6 to 14 cm depending upon the electrode types (rod and parallel plate) and their configurations where the potential applied electrode was placed at top or bottom of the cavity. Temperature uniformity improved with increased electrode gap, and the parallel plate electrode design provided the higher heating rates at lower electrode gaps. The heating rate was lower at higher electrode gaps while contradicted results were obtained in the staggered through field electrode designs with respect to the electrode gap. The electromagnetic field distribution also differed significantly in these systems. The results of this study are considered to have the potential to be applied in industrial scale RF processing studies specially with more than one RF cavity systems.