Resistance and Q-factor calculation of single and double layer coils with split circular pattern

Abstract

In the paper, resistance and quality factor (Q-factor) of single and double layer coils with split circular pattern are calculated according to frequency range from 125 kHz to 6.78 MHz to design an effective coil in magnetic coupling wireless power transfer. For calculation, method of volume filament model (VFM) is adopted. It is shown that coils of a split double layer circular pattern have lower resistance and higher Q-factor than those of a split single layer. For comparison, total metal thickness for single and double layer is the same. With higher frequency in the megahertz frequency range, Q-factors for the double layer coils are higher than those for the single layer. Also, Q-factor difference between single and double layer coils increases. Also, when total metal of the coils becomes thicker, resistance is reduced and Q-factor is improved. Additionally, the differences of resistance and Q-factor between single and double layer are reduced with thicker metal. For verification, several single and double layer coils of a split circular pattern with 0.5 oz, 1 oz, and 2 oz metal thick are fabricated. The calculation results are verified with the measurement and simulation results.