The main purpose of Inductive Power Transmission (IPT) is efficient power transfer. Yet the ability to localize the receiver is itself an interesting goal. In Qi standards for wireless power transfer, the localization is performed by using a coils array. The resolution of localization is equal to the diameter of the coils in the transmitter array. Decreasing the diameter of coils in transmitters increases the resolution of localization but also reduces the range of power transfer. IPT is used in inductive RFID (Radio Frequency Identification) where a trade-off between resolution of localization and range of tag detection arises. This article proposes an original system making it possible to modify the resolution and the distance of operation independently. Calculations and simulations are implemented in MATLAB software. Experiments in low frequency validate the method and show the system capability to localize the receiver with good accuracy, with mean absolute error of 4 mm for localizing a receiver coil of 1 cm radius positioned in a box with dimensions 20*20*10 cm. Transmitter is a grid of 9 coils of 3.3 cm radius. After localization, the magnetic field is steered in the direction of the receiver to obtain a more efficient power transfer.

IPT (Inductive Power Transfer) is an approach based on magnetic coupling to realize a wireless power transfer (WPT) system. In applications using IPT as a mean for transferring power, like RFID, it is of great interest to have a free positioning system, meaning with fewer constraints on relative positioning and orientation between the sender and the receiver. One of the problems which face the free positioning WPT by using IPT is the great sensitivity of the system to lateral and orientational misalignment between the sender and the receiver of power. This could hugely reduce the efficiency of the whole system for certain lateral and orientational misalignments, resulting in null points for the coupling coefficient, therefore no power transfer or no detection in case of RFID. In this work, we propose a reconfigurable antenna which changes its structure by turning on and off specific parts of itself. This will guarantee the effective power transfer in the range of interest, regardless of the lateral and orientational misalignments between the sender and the receiver. The same system can be used to increase the RFID read range by steering the magnetic field in certain direction. In general, the steering of the magnetic field could be used to achieve more efficient power transfer.