Analysis of wireless energy transfer to multiple devices using CMT

In this paper, characteristics of wireless energy transfer to multiple devices is presented. Using the coupled mode theory (CMT), coupling behavior of resonant coils is analyzed, by assuming that resonant coils between devices are independent. Maximum efficiency of energy transfer to resonant coils of devices and time for the maximum energy transfer are obtained. It is shown that the energy transfer to each device is divided with the rate of the square of the coupling coefficient. It is also shown that the number of devices should be decided carefully to design the wireless energy transfer system since total efficiency is likely to be saturated despite devices increasing. For verification, an equivalent circuit model is derived and using the model, reflection and transmission are simulated. Theoretical results are compared with simulated ones.