High impedance transponder with improved backscatter modulator for electronic identification system
DC
First Claim
1. A transponder for an electronic identification system including an input connected to transponder circuitry, the transponder being characterized in that an input impedance at the input thereof is at least 400Ω
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Abstract
A transponder 20 for an electronic identification system transponder is characterized in that it presents a high input impedance (>400Ω) at an input thereof which is directly connected to an antenna 22 with a matched high input impedance. The transponder is aimed at improving the voltage recovered on capacitor C2 from an interrogation signal and thus the operational range of the system. The modulator 30 of the transponder is arranged to backscatter modulate the interrogation signal at a modulation depth of less than 80%, preferably in the order of 30%. This also results in an improvement of the operational range of the system.
104 Citations
15 Claims
- 1. A transponder for an electronic identification system including an input connected to transponder circuitry, the transponder being characterized in that an input impedance at the input thereof is at least 400Ω
- 9. A transponder including transponder circuitry including a modulator for modulating a received energizing signal with a response signal at a modulation depth of less than 80%.
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14. A transponder for an electronic identification system, the transponder including:
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an antenna connected to an input of transponder circuitry; the transponder circuitry including; an energizing signal detector connected to the antenna; a storage capacitor connected to the detector to store a voltage retrieved from the energizing signal; a modulator connected to the antenna; and circuitry for generating a control signal for the modulator; the modulator being arranged in response to the control signal to modulate the energizing signal at a modulation depth of less than 80%.
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15. An electronic identification system including
an interrogator for transmitting an energizing signal; -
a plurality of transponders; each transponder including an antenna connected to transponder circuitry; the transponder circuitry including; an energizing signal detector connected to the antenna; a storage capacitor connected to the detector to store a voltage retrieved from the energizing signal; a modulator connected to the antenna; and circuitry for generating a control signal for the modulator; the modulator being arranged in response to the control signal to modulate the energizing signal at a modulation depth of less than 80%.
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Specification
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- Resources
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Current AssigneeZebra Technologies Corporation
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Original AssigneeData Investments Ltd.
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InventorsTurner, Christopher Gordon Gervase, Proctor, David Edwin
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Primary Examiner(s)SWANN III, GLEN R
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Application NumberUS09/138,560Time in Patent Office610 DaysField of Search340/572.7, 340/572.1, 340/693.1, 342/51, 342/27, 342/44US Class Current340/572.7CPC Class CodesG06K 19/0723 the record carrier comprisi...
