Abstract: The portable object comprises a circuit on a double-sided printed circuit with a coil etched on the printed circuit, the coil comprising a plurality of alternating turns etched on each of the faces of the card, with each turn being an open turn connected at each end by means of a respective via passing through the card to the corresponding adjacent end of the next turn disposed on the opposite face of the card, the successive turns thus being connected in series in alternating and concentric manner by means of a set of vias.

Abstract: The portable object includes an electronic circuit powered by an internal battery and having a data memory; it enables data to be interchanged with the outside without making direct electrical contact. It comprises a pierceable zone forming a region of the housing of the object, and a plurality of contact areas inside the housing and in register with the pierceable zone, the contact areas being connected to power supply lines for the electronic circuit, the areas being suitable for being put into contact with electrically conductive spikes connected to an external power supply circuit and pushed through the pierceable zone, thereby enabling the electronic circuit of the object to be powered and thus making good any exhaustion or failure of its internal battery, in particular in order to provide access to the data memory.