Tunable Dual Band Wireless Power Transfer (TDB-WPT) System for Short Range Applications

This brief introduces a novel design to transfer wireless power in dual bands with reconfiguration operation. The idea is obtained by transferring power through one fixed band at 190 MHz and the second band is tuned from 1.1 GHz to 1.4 GHz. The top layer is constructed of a spiral resonator coupled with the feed line. The bottom layer contains a spiral resonator. The varactor diode is attached to the spiral at the top layer which is responsible for the tuned band. Further, a surface mounted (SMD) capacitor is added to the spiral at the bottom layer for getting a fixed band. The system has a size of 20 $\times $ 20 mm2 and the transmission distance between the coupled resonators is 10 mm. The system achieved an efficiency of 97 % at the fixed band of 190 MHz while the average efficiency is 95 % over the tuned band. A good agreement between the measurement and the simulation is achieved.