Asymmetric Transformer Design With Multiband Frequency Response for Simultaneous Power and Data Transfer

This article presents a novel approach to generate multiple passbands from an asymmetric two-coil transformer. The details of the asymmetry between the primary and secondary coils control the passbands' location and bandwidth (BW). A cylindrical asymmetric connector was designed and prototyped. The S-parameters were measured with a vector network analyzer (VNA), which shows a very good match with the theoretical model up to the second passband frequency (10 MHz-1 GHz). The first passband is used for power transfer since the lower frequency is better for power transmission. The higher frequency of the second passband can be used to transmit high BW data. A carrier signal centered at the second passband frequency was used to modulate digital data at the transmitter side and demodulated at the receiver side. This connector can be used for transmitting only power, or only data, or both power and data simultaneously. We demonstrate 19 mW of power transfer and 100 Mb/s of data transfer simultaneously in a 5-mm-diameter and 7-mm high cylindrically coupled structure. To the best of our knowledge, it is the highest data rate demonstrated through a wireless power transfer link.