The carrier comprises a male part (1) and a female part (2), wherein the male part (1) has a stud (3) able to cooperate with a cavity (4) of the female part (2), wherein the stud (3) contains a ferrite rod (5) on his central axis (7). Said female part (2) comprises said antenna coil (6) so that when the stud (3) fully cooperates with the cavity (4) of the female part (2) through positioning means (9,10), the ferrite rod (5) is placed in the center (8) of the antenna coil (6).