Sizing of an electromagnetic transponder system for an operation in extreme proximity
First Claim
1. An electromagnetic transponder of the type including a parallel oscillating circuit adapted to being excited by a series oscillating circuit of a read/write terminal when the transponder enters the field of the terminal, wherein the components of the oscillating circuit of the transponder are sized so that the coupling coefficient between the respective oscillating circuits of the terminal and of the transponder rapidly decreases when the distance separating the transponder from the terminal becomes greater than a predetermined value.
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Accused Products
Abstract
A system of contactless electromagnetic transmission between a terminal including a series oscillating circuit for generating an electromagnetic field and a transponder including a parallel oscillating circuit, these oscillating circuits being sized so that the coupling coefficient between them strongly decreases when the distance separating the transponder from the terminal becomes greater than a predetermined value.
105 Citations
13 Claims
- 1. An electromagnetic transponder of the type including a parallel oscillating circuit adapted to being excited by a series oscillating circuit of a read/write terminal when the transponder enters the field of the terminal, wherein the components of the oscillating circuit of the transponder are sized so that the coupling coefficient between the respective oscillating circuits of the terminal and of the transponder rapidly decreases when the distance separating the transponder from the terminal becomes greater than a predetermined value.
- 9. A terminal for generating an electromagnetic field adapted to cooperating with at least one transponder when said transponder enters this field, including a series oscillating circuit for generating the electromagnetic field, the series oscillating circuit being sized so that the coupling coefficient between the respective oscillating circuits of the terminal and of the transponder strongly decreases when the distance separating the transponder from the terminal becomes greater than a predetermined value.
Specification