Protection of a radio frequency transmit-receive terminal against electromagnetic disturbances
First Claim
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1. An antenna circuit coupleable to a device of transmission/reception by inductive coupling, comprising:
- a first inductive element electrically coupled in a parallel association with a capacitive element, the parallel association having a first node directly connected to a first end of the first inductive element and a first end of the capacitive element, the parallel association having a second node directly connected to a second end of the second inductive element and a second end of the capacitive element;
a first dual purpose inductance electrically coupled directly between the first node of the parallel association and a first terminal of a switch; and
a second dual purpose inductance electrically coupled directly between the second node of the parallel association and a second terminal of the switch, the first and second dual purpose inductances configurable by the switch to cooperate as a second inductive element in the parallel association.
1 Assignment
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Accused Products
Abstract
An antenna circuit for a device of transmission/reception by inductive coupling, including a first inductive element in parallel with a capacitive element and, between each node of the parallel association and two terminals of a switch, a second inductive element.
9 Citations
23 Claims
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1. An antenna circuit coupleable to a device of transmission/reception by inductive coupling, comprising:
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a first inductive element electrically coupled in a parallel association with a capacitive element, the parallel association having a first node directly connected to a first end of the first inductive element and a first end of the capacitive element, the parallel association having a second node directly connected to a second end of the second inductive element and a second end of the capacitive element; a first dual purpose inductance electrically coupled directly between the first node of the parallel association and a first terminal of a switch; and a second dual purpose inductance electrically coupled directly between the second node of the parallel association and a second terminal of the switch, the first and second dual purpose inductances configurable by the switch to cooperate as a second inductive element in the parallel association. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method to operate an antenna circuit of an inductively coupled transmission/reception device, comprising:
controlling a switch, the switch having a first terminal, a second terminal, and a control terminal, wherein the first terminal is electrically coupled directly to a first dual purpose inductance, the first dual purpose inductance electrically coupled directly to one end of a parallel arrangement including a capacitive element and an antenna, wherein the second terminal is electrically coupled directly to a second dual purpose inductance, the second dual purpose inductance electrically coupled directly to an opposite end of the parallel arrangement, the controlling including opening the switch when the transmission/reception device is operating in a reader mode and closing the switch when the transmission/reception device is operating in a card mode. - View Dependent Claims (10, 11, 12, 13)
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14. A device having an antenna circuit inductively coupled to a transmission/reception circuit, comprising:
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an antenna inductance; a first dual purpose inductance; a second dual purpose inductance, a capacitive element connected in a parallel association with the antenna inductance, the parallel connection formed at a first node means and a second node means for electrically connecting the parallel association directly to the first and second dual purpose inductances; a switch having a first terminal and a second terminal, wherein the first dual purpose inductance is coupled between the first switch terminal and the first node means, and wherein the second dual purpose inductance is coupled between the second switch terminal and the second node means; and a control circuit to open and close the switch wherein closing the switch places the first and second dual purpose inductances in a series arrangement with each other, the series arrangement connected in parallel with the antenna inductance and the capacitive element. - View Dependent Claims (15, 16, 17, 18, 19)
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20. An antenna circuit coupleable to a device of transmission/reception by inductive coupling, comprising:
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a switch having first and second terminals; an inductive element; a capacitive element; a parallel circuit having first and second connection points at which the inductive element and the capacitive element are connected to each other in parallel; a first dual purpose inductance connected between the first connection point of the parallel circuit and the first terminal of the switch; and a second dual purpose inductance connected between the second connection point of the parallel circuit and the second terminal of the switch, the switch configured to cause the first and second dual purpose inductances to cooperate as a second inductive element in the parallel circuit. - View Dependent Claims (21, 22, 23)
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Specification