To improve wireless power transmission efficiency by using coil arrays

A new method of using coil arrays at both the transmitter and receiver sides is introduced for wireless power transmission (WPT) employing the technique of mid-range strong magnetic resonant coupling. Dual two-coil arrays are designed as the WPT system, where one array is used for the power transmitter while the other array is applied for the power receiver. It is shown that a power transmission efficiency of well over 50% at a transmission separation of 50 cm can be achieved. This efficiency is much higher than the usual cases of not using coil arrays both on the transmitting and receiving sides. Also, the optimized values of load resistors connected to the receiver coil elements show that the proposed WPT system is especially suitable for charging batteries with very low internal resistances such as batteries in laptops and mobile phones.