To prevent the characteristics of the antenna of a transponder from being deteriorated even when this transponder is placed in a relatively high temperature atmosphere, and to surely operate the transponder even when an article on which the transponder is mounted is made of any material.
An electromagnetic masking shield plate 13 is formed by spreading soft magnetic powder or soft magnetic flake in heat-resistant plastic, and a coil 14 formed on the surface of the electromagnetic masking shield plate 13 is spirally formed with an axial line orthogonal crossing the electromagnetic masking shield plate 13 as a center. An IC chip 16 mounted on the surface of the electromagnetic masking shield plate 13 is electrically connected to the coil 14, and specific information different for each mounting article 12 is stored in the IC chip 16. The heat-resistant plastic is provided with heat resistance to its softness or deterioration in a heating atmosphere which is at least 200°C, and the electric resistivity of the electromagnetic masking shield plate 13 is set so as to be not less than 1×106 Ωcm.
TAKAHASHI EIJI
NAKAZATO MINORU
ISHIYAMA KOICHI
