| 摘要 |
The present invention relates to a tag-use antenna allowing a miniaturization while maintaining a constant minimal change of a communication distance. The tag-use antenna has a feed part of a folded dipole antenna of a size of 53 mm long and 7 mm wide being connected to, and equipped with, an LSI chip of Rc=500 ohms and Cc=1.4 pF and is covered with plastic resin 13 of the dielectric constant epsilonr=3 and thickness of t=0.75 mm on both sides of the antenna. The dipole part of 1 mm wire path width of the tag-use antenna is formed in a rectangular spiral by being bent inward from both ends at bending parts at four places. The entire length of the dipole antenna when extending the four bending parts straight is featured so as to be shorter than one half of a resonance wavelength of the antenna. An inductance part is featured in the intermediate part of the both dipole parts in the neighborhood of the center of the antenna. The inductance part is connected to the chip equipment part in parallel with the both dipole parts.
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