  In conventional inductive wireless power devices, the energy is transferred
via only reactive near fields, which is equivalent to non-radiative F\"orster
energy transfer in optics. Radiation from transmitting and receiving coils is
usually considered as a parasitic effect that reduces the power transfer
efficiency. As long as the distance between the two antennas is small as
compared to the antenna size, conventional WPT devices offer rather high power
transfer efficiency, of the order of 80-90\%. However, for larger distances,
the transfer efficiency dramatically drops, making such devices not practical.
In this paper, we develop a dynamic theory of wireless power transfer between
two small loop antennas, clarify the role of far-field radiation, and find a
possibility to realize efficient wireless power transfer at large distances
utilizing the regime of radiation suppression due to optimized mutual dynamic
interactions between the transmitting and receiving antennas. The analytical
results have been validated by simulations and measurements, and they open a
possibility to greatly expand the range of distances of compact wireless power
transfer devices. The developed theory can be applied also to coupling between
antennas of different types and to energy transfer between nano-objects.
