| 摘要 |
The invention concerns a reader antenna in a system of identification or of access to a zone with controlled access comprising a reader designed to detect responding electromagnetic signals coming from a contact-free portable object such as an ISO card or a disposable ticket (46), the responding magnetic signals being transmitted by an antenna (48) located in the portable object in reply to the reception of electromagnetic signals transmitted by the reader antenna when the bearer of the portable object presents the portable object in front of the reader. The antenna comprises n groups of turns (20, 22, 24) arranged in series wherein each group of k-1 turns includes a number of Nk-1 turns less than the number of Nk turns of the group of k turns (k ranging between 2 and n) and is spaced apart from the group of k turns by a distance Dk-1 greater than a predetermined value, the turns of all the groups being wound in the same direction.
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