  In order to ensure the fastest wireless energy transfer from a source to the
user one needs to maximize the channel capacity for power transport. In
communications technologies, the concept of MIMO (multiple input, multiple
output) exploits the idea of sending signals via many different rays which may
reach the receiver. However, if we are concerned with the task of energy
transfer, still only one mode is exploited, even if multiple antennas are used
to send power to the receiver. In the near-field scenario, this is the magnetic
dipole mode of receiving coil antennas. In the far-field scenario, this is the
propagating plane wave TEM mode. Recently, it was shown that using special
artificial materials it is possible to ensure that all electromagnetic modes of
free space are conjugately matched to the modes of a material body and, thus,
all modes deliver power to the body in the most effective way. Such a
fascinating feature is acquired because the conjugate matching does not concern
only the propagating modes but, most importantly, is applied to all evanescent
modes. However, coupling to higher-order (mostly evanescent) modes is weak and
disappears in the limit of an infinite planar boundary. We show that properly
perturbing the surface of the receiving or emitting body with, for example,
randomly distributed small particles we can open up channels for
super-radiation into far zone. The currents induced in the small particles act
as secondary sources which send the energy to travel far away from the surface
and, reciprocally, receive power from far-located sources. We theoretically
predict about 20-fold power transfer enhancement between the conjugately
matched power-receiving body (as compared with the ideal black body) and
far-zone sources. Reciprocally, the proposed structure radiates about 20 times
more power into far zone as compared with the same source over a perfect
reflector.
