Electromagnetic field generation antenna for a transponder
First Claim
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1. An apparatus comprising:
- an antenna for generating an electromagnetic field for an electromagnetic transponder, the antenna comprising;
a first inductive element operative to connect to two terminals of application of an excitation voltage; and
a parallel resonant circuit coupled with the first inductive element to extend a range of an electromagnetic field emitted by the first inductive element, andwherein the parallel resonant circuit comprises a second inductive element and a control switch connected to the second inductive element.
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Abstract
An antenna generating an electromagnetic field for an electromagnetic transponder and a terminal provided with such an antenna. The antenna comprises a first inductive element designed to be connected to two terminals employing an energizing voltage, and a parallel resonant circuit coupled with the first inductive element.
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Citations
32 Claims
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1. An apparatus comprising:
an antenna for generating an electromagnetic field for an electromagnetic transponder, the antenna comprising; a first inductive element operative to connect to two terminals of application of an excitation voltage; and a parallel resonant circuit coupled with the first inductive element to extend a range of an electromagnetic field emitted by the first inductive element, and wherein the parallel resonant circuit comprises a second inductive element and a control switch connected to the second inductive element. - View Dependent Claims (2, 3)
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4. An apparatus comprising:
an antenna for generating an electromagnetic field for an electromagnetic transponder, the antenna comprising; a first inductive element operative to connect to two terminals of application of an excitation voltage; and a parallel resonant circuit coupled with the first inductive element to extend a range of an electromagnetic field emitted by the first inductive element, wherein the parallel resonant circuit comprises a second inductive element and a control switch connected to the second inductive element, wherein the first inductive element is formed of several inductances organized in a network, and wherein the several inductances comprise seven planar windings. - View Dependent Claims (5)
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6. An apparatus comprising:
an antenna for generating an electromagnetic field for an electromagnetic transponder, the antenna comprising; a first inductive element operative to connect to two terminals of application of an excitation voltage; and a parallel resonant circuit coupled with the first inductive element to extend a range of an electromagnetic field emitted by the first inductive element, wherein the parallel resonant circuit comprises a second inductive element and a control switch connected to the second inductive element, wherein the first inductive element and the second inductive element are formed of planar windings, and wherein a value of the second inductive element is greater than a value of the first inductive element.
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7. An apparatus comprising:
an antenna comprising; a first inductive element configured to connect to an excitation signal; and a resonant circuit to extend a range of an electromagnetic field emitted by the first inductive element, the resonant circuit being configured to inductively couple to the first inductive element, the resonant circuit comprising a second inductive element and a control switch connected to the second inductive element, wherein the first inductive element and the second inductive element each comprise a planar winding, wherein a plane of the first inductive element and a plane of the second inductive element are substantially parallel, and wherein the first inductive element comprises a plurality of planar windings. - View Dependent Claims (8, 9, 10, 11)
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12. An apparatus comprising:
an antenna comprising; a first inductive element configured to connect to an excitation signal; and a resonant circuit to extend a range of an electromagnetic field emitted by the first inductive element, the resonant circuit being configured to inductively couple to the first inductive element, the resonant circuit comprising a second inductive element and a control switch connected to the second inductive element, wherein the first inductive element and the second inductive element each comprise a planar winding, wherein a plane of the first inductive element and a plane of the second inductive element are substantially parallel, wherein the resonant circuit further comprises a first capacitor, and wherein the first capacitor is connected in parallel to the second inductive element, and wherein a value of the first capacitor and a value of the second inductive element define a natural frequency approximately equal to a frequency of the excitation signal.
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13. An apparatus comprising:
an antenna comprising; a first inductive element configured to connect to an excitation signal; and a resonant circuit to extend a range of an electromagnetic field emitted by the first inductive element, the resonant circuit being configured to inductively couple to the first inductive element, the resonant circuit comprising a second inductive element, wherein the first inductive element and the second inductive element each comprise a planar winding, wherein a plane of the first inductive element and a plane of the second inductive element are substantially parallel, wherein the resonant circuit further comprises a first capacitor, and wherein the first capacitor is connected in parallel to the second inductive element, and wherein the resonant circuit further comprises a switch. - View Dependent Claims (14, 15)
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16. An apparatus comprising:
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an antenna comprising; a first inductive element configured to connect to an excitation signal; and a resonant circuit to extend a range of an electromagnetic field emitted by the first inductive element, the resonant circuit being configured to inductively couple to the first inductive element, the resonant circuit comprising a second inductive element and a control switch connected to the second inductive element, wherein the first inductive element and the resonant circuit are disposed on a same substrate.
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17. An apparatus comprising:
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an antenna comprising; a first inductive element configured to connect to an excitation signal; and
a resonant circuit to extend a range of an electromagnetic field emitted by the first inductive element, the resonant circuit being configured to inductively couple to the first inductive element, the resonant circuit comprising a second inductive element and a control switch connected to the second inductive element,wherein the first inductive element and the resonant circuit are disposed on a same substrate wherein the first inductive element comprises a plurality of planar windings. - View Dependent Claims (18, 19, 20, 21)
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22. An apparatus comprising:
an antenna comprising; a first inductive element configured to connect to an excitation signal; and a resonant circuit to extend a range of an electromagnetic field emitted by the first inductive element, the resonant circuit being configured to inductively couple to the first inductive element, the resonant circuit comprising a second inductive element and a switch connected to the second inductive element, wherein the first inductive element and the resonant circuit are disposed on a same substrate, wherein the resonant circuit further comprises a first capacitor, and wherein the first capacitor is connected in parallel to the second inductive element, and wherein a value of the first capacitor and a value of the second inductive element define a natural frequency approximately equal to a frequency of the excitation signal. - View Dependent Claims (23, 24)
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25. A terminal for generating a high-frequency electromagnetic field for at least one transponder entering this field, the terminal comprising:
an antenna for generating an electromagnetic field for the at least one transponder, the antenna comprising; a resonant circuit and an excitation circuit magnetically coupled to the resonant circuit, the excitation circuit including a first inductive element and having no capacitive element, said resonant circuit including a second inductive element and a control switch connected to the second inductive element, a value of which is chosen to be greater than a value of the first inductive element with a ratio depending on a desired field amplification for extending a range of an electromagnetic field emitted by the excitation circuit. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
Specification