Mid-range kHz electric resonance coupling wireless power tranfser

This paper describes mid-range electrical resonance wireless power transfer in kHz range. Wireless power transfer using electrical field is minor since this method is understood only for close-range applications. However, our experimental units, the resonance frequency of which is 85 kHz, achieved 180 mm distance power transmission by vector network analyzer (VNA) measurement while keeping peak efficiency 68 %. In case of frequency response analyzer (FRA) measurement, the units can transfer power the most to the load at 300 mm but the efficiency is low. The closer the distance between the units, the better the efficiency is.