The interaction with the medium (e.g. body capacitance) can cause energy to deflect back to the source, as occurs in the "reactive" near field. Or the interaction with the medium can fail to return energy back to the source, but cause a distortion in the electromagnetic wave that deviates significantly from that found in free space, and this indicates the "radiative" near-field region, which is somewhat further away. Another intermediate region, called the "transition zone", is defined on a somewhat different basis, namely antenna geometry and excitation wavelength.