Tire comprising a radiofrequency transponder

A tire casing (100) that is toroidal in shape about a reference axis and equipped with a passive radiofrequency transponder (1, 1bis, 1ter) and comprises:

• a crown block (82) comprising a crown reinforcement (86) having an axial end (861) at each of its edges, and a tread (89), connected at each of its axial ends (821) to a bead (84) having an interior end (841) situated axially and radially on an inside of the bead (84) with respect to the reference axis, by a sidewall (83);
• a carcass reinforcement comprising at least one carcass reinforcement layer formed of mutually parallel reinforcing elements inserted between two skim layers of elastomer compound, the at least one carcass reinforcing layer being anchored in each of the beads (84) by being turned up around an annular bead wire (85) to form a main part of the at least one carcass reinforcement layer (87), extending from one bead wire (85) to the other and situated radially on an inside with respect to the crown block (82), and a turn-up of the at least one carcass reinforcement layer (88) in each of the beads (84);
• a second layer of elastomer compound (93) forming an exterior surface of the tire casing (100) in a region of the bead (84), the second layer of elastomer compound (93) being intended to come into contact with a rim;
• a third layer of elastomer compound (94) situated radially on an outside in contact with the second layer of elastomer compound (93) forming an exterior surface of the sidewall (83);
• the passive radiofrequency transponder (1, 1bis, 1ter) comprising an electronic portion (20) and a radiating dipole antenna (10) consisting of a single-strand helicoidal spring defining a helix pitch P, a winding diameter D, a midplane (19) and a wire diameter defining an interior diameter (13) and an exterior diameter (15) of the radiating antenna (10), of which a length (L0) is designed to communicate on a frequency band with an external radiofrequency reader defining a first longitudinal axis (11), a central region and two lateral regions along the first longitudinal axis (11),
• the electronic portion (20) comprising an electronic chip and a primary antenna of coil type comprising at least one turn, and defining a second longitudinal axis and a midplane (21) perpendicular to the second longitudinal axis, the primary antenna being electrically connected to the electronic chip and electromagnetically coupled to the radiating dipole antenna (10), the primary antenna being circumscribed inside a cylinder of which an axis of revolution is parallel to the second longitudinal axis and in which the diameter is greater than or equal to one third of the interior diameter (13) of the radiating antenna (10) situated plumb with the primary antenna, and
• the passive radiofrequency transponder (1, 1bis, 1ter) being arranged in such a way that the first (11) and second longitudinal axes are parallel and that the midplane of the primary antenna (21) is positioned in the central region of the helical spring (10),
• wherein, with the radiating dipole antenna (10) comprising a second region (102) in which the radiating dipole antenna (10) is situated plumb with the electronic portion (20) and a first region (101, 101a, 101b) in which the radiating dipole antenna (10) is not situated plumb with the electronic portion (20), a ratio between a helix pitch (P1) and a winding diameter (D1) for at least one loop of the helical spring in the first region (101, 101a, 101b) is greater than 0.8,
• wherein the ratio between the helix pitch (P1) and the winding diameter (D1) of each loop of the helical spring in the first region (101, 101a, 101b) of the radiating dipole antenna (10) is less than 3,
• wherein the radiating dipole antenna (10) is situated plumb with at least two reinforcement elements of the main part of the at least one carcass reinforcement layer (87), and
• wherein the passive radiofrequency transponder is situated axially on an outside of the interior end (841) of the bead (84) and radially between the radially outermost end (851) of the bead wire (85) and the axial end (861) of the crown reinforcement (86).