Implantable subcutaneous device of biocompatible material that can receive data and energy by electromagnetic coupling with at least one external device is disclosed. The implantable device bears an airtight housing and a magnet that can hold the other external device centered with the implantable device. The housing bears a hollow crown containing at least electronic device(s) and a coil, and a bottom sealing the opening of the crown in an airtight manner. The magnet has dimensions compatible with a central housing formed by the so-called internal wall of the crown and in which it is positioned.