A ferrite reflector-based optimization design of magnetic resonant wireless power transfer (WPT) system to improve transmission efficiency is proposed. The WPT system composed of four resonators is considered as a two-port network to deduce the transfer efficiency. Then a magnetic resonant WPT system whose receiving and transmitting coils have a diameter of 30cm is designed and manufactured. The measured transmission efficiency is above 90% at the distance of 30cm while decreases to about 40% when the distance increases to 60cm. Measured results are in good agreements with simulated ones. Based on this WPT system, two different ferrite reflectors are introduced to improve the transmission efficiency. Results show that the different size of magnetic reflectors may have positive or negative effects on transmission efficiency. By optimizing the ferrite reflector, the maximum 15% improvement of transmission efficiency is obtained at the distance range of 30cm to 90cm.
