Wireless Charging Platform for Dual-Band Magnetic Resonance

This text investigates a dual-band wireless charging platform utilizing magnetic resonance. The platform operates at 6.78 and 13.56 MHz, and is capable of charging two mobile devices simultaneously. Physical measurements of the resonant coils indicate that the S-11 for 13.56 MHz and the S-22 for 6.78 MHz are 29.45 and -26.87 dB, respectively. The So values of the receiving coil for 6.78 and 13.56 MHz are 24.12 and 19.98 dB, respectively. Furthermore, the effect between the two different frequencies of the transmitter coil is low when they both work simultaneously, implying that the platform can charge batteries for several mobile devices simultaneously. The S parameters can be used to calculate the efficiency of the wireless charging platform, which is approximately 33.11% at 6.78 MHz and 25.12% at 13.56 MHz. Furthermore, the results indicate that the efficiency of the rectifier circuits is greater than 50% at 6.78 MHz and greater than 80% at 13.56 MHz.