Localization of receivers using phased-array wireless power transfer systems

Wireless battery charging has been incorporated into an increasing number of commercial electronics with power requirements ranging from a few milliwatts to several hundred watts. With this growing number of deployed devices, there is a necessity to quickly locate and charge them individually. Conventional localization techniques either require intelligence and extra hardware or are limited to merely detecting the presence of an object and not its position. In the proposed localization technique, we use two wireless power transmitters (TX) operating at the the same frequency. The phase difference between the two TXs can be controlled. The forward/reflected signals are measured from each TX and are used to accurately localize the receiver in a two dimensional space. This system does not require additional hardware on the TX or RX side. The entire detection process can be confined to the transmitter firmware. We also formulate a simple localization parameter using the reflected signals to prove the concept of localization.