Passive dynamic antenna tuning circuit for a radio frequency identification reader
First Claim
1. A tunable resonant circuit for a radio frequency identification (RFID) reader, wherein the reader transmits an activation signal to a transponder, the tunable resonant circuit comprising:
- at least one resonant frequency-determining element;
a dynamic tuning network in series with the resonant frequency-determining element for tuning the resonant circuit to a first resonant frequency value when the activation signal is on and to a second resonant frequency value when the activation signal is off.
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Abstract
A resonant antenna circuit for a radio frequency identification (RFID) reader generates an electrical signal for activating a passive identification tag. The identification tag in turn generates a coded electrical signal that is detected by the reader. The electrical characteristics of the resonant circuit are dynamically altered so that the antenna performs more optimally as a transmitter and receiver for different types of transponders. The resonant circuit uses only passive components and the instantaneous resonant frequency tuning point is determined by the state of the activation signal transmitter.
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Citations
17 Claims
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1. A tunable resonant circuit for a radio frequency identification (RFID) reader, wherein the reader transmits an activation signal to a transponder, the tunable resonant circuit comprising:
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at least one resonant frequency-determining element;
a dynamic tuning network in series with the resonant frequency-determining element for tuning the resonant circuit to a first resonant frequency value when the activation signal is on and to a second resonant frequency value when the activation signal is off. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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- 13. A variable bandwidth antenna circuit for a radio frequency identification (RFID) reader, wherein the reader transmits an activation signal to a transponder, the antenna circuit comprising a dynamic bandwidth adjustment network for establishing a first bandwidth value when the activation signal is on and a second bandwidth value when the activation signal is off.
Specification