A device for non-contact transmission of electrical signals or energy between two parts mobile relative to each other comprising electromagnetic near-field coupler elements on the two parts, wherein the coupler elements on at least one part form a cascade circuit terminated in a manner substantially free from reflection, and each coupler element is an independent resonance system having a resonance frequency higher than a highest frequency of wide-band signals to be transmitted. An alternatively structured device in which each coupler element on one part includes an element that resonates independently and has a resonance frequency approximately equal to the frequency of signals or energy to be transmitted including developments in which the coupler elements operate on differential signals, or analyzer means determine the spacing between the two parts, or at least one part comprises symmetrical lines for supplying differential energy signals to two coupler elements.