Mitigation of Antenna Displacement with Array Antenna for Data Transmission in Wireless Power Transfer System

Magnetic resonance wireless power transfer is expected to be one of the prevalent schemes because of its high efficiency and long transmission range. However, in this scheme, there is a problem that the characteristics of a transmission channel changes in according with the distance between coil antennas. This paper investigates the performance of data transmission with an array antenna in a wireless power transfer system. In the assumed system, the same antennas for wireless power transfer are used for data transmission. The assumed system uses multiple transmit antennas and beamforming is realized by shifting the phases of signals in a transmitter. Numerical results obtained through computer simulation show that the proposed scheme can mitigate the dependently of a bit error rate (BER) to the distance between the antenna coils. The variation of the performance is suppressed within 1–3 dB at the BER of (Formula presented.) in the case of two transmit antennas. In addition, the system with two transmit antennas achieves 2 dB or more improvement in term of the BER performance than that with a single antenna at specific antenna distances.