Effects of size mismatch in dual-function near-field antennas

Effective deployment of near-field wireless power transfer mechanisms requires the concurrent transfer of status and control data between the coupled terminals. The implementation of simultaneous data and power transfer requires an understanding of the interplay between the transfer efficiency and bandwidth. This paper examines the transfer efficiency and bandwidth of links with independently matched circular loop antennas. Three scenarios are investigated. In the first, both paired antennas have the same size. The second and third scenarios deal with bigger and smaller transmit antennas relative to the receive antenna. The results suggest that equal-sized antennas provide a higher level of efficiency than with size mismatched antennas. Further, a marginal increase in link bandwidth is observed for the case of a larger transmit antenna relative to the receive antenna.