Wireless power transmission to a device shielded by unknown electromagnetic media

This paper presents a method to realize wireless power transmission to a device shielded by unknown electromagnetic media based on measurement. An antenna array is used to transmit the power to the receiving device. The transmitting array elements and receiving device constitute a multi-port network, and can be characterized by the S-parameters. The power transmission efficiency can be expressed in terms of the S-parameters, and its maximum possible value can be calculated. Also, the corresponding excitation distribution for the transmitting elements can be obtained. With the calculated excitation distribution, a feeding network can be designed to feed the transmitting elements and the whole wireless power transmission system can be then constructed. An example is presented to demonstrate the method.