Wireless transponder for a security system

1. An apparatus, comprising:

a first receiver configured to receive a reply signal at a first frequency from a marker positioned remotely from said receiver, and within an interrogation zone for an electronic article surveillance system, and said first receiver to convert said reply signal to a second frequency;

a first transmitter to connect to said receiver, said first transmitter to transmit said reply signal at said second frequency; and

a second receiver configured to receive said reply signal at said second frequency, said second receiver to convert said reply signal from said second frequency to said first frequency, and send said reply signal to a controller.

2. The apparatus of claim 1 , wherein said first frequency comprises a lower frequency in a range between 50 Hertz to 13 Megahertz, and said second frequency comprises a higher frequency in a range between 13.01 Megahertz to 2.45 Gigahertz.

3. The apparatus of claim 1 , wherein said first frequency comprises a higher frequency in a range between 13.01 Megahertz to 2.45 Gigahertz, and said second frequency comprises a lower frequency in a range between 50 Hertz to 13 Megahertz.

4. The apparatus of claim 1 , wherein said first frequency corresponds to said second frequency.

5. The apparatus of claim 1 , wherein said first receiver comprises an inductor-capacitor antenna.

6. The apparatus of claim 1 , wherein said first transmitter comprises: an amplifier to receive as input said reply signal and output an amplified signal; a local oscillator to provide an oscillation signal; and a mixer to connect to said amplifier and local oscillator, said mixer to receive as input said amplified signal and said oscillation signal and output said reply signal at said second frequency.

7. The apparatus of claim 1 , further comprising a power source to provide power to said first receiver and said first transmitter, said power source to comprise a battery powered circuit.

8. The apparatus of claim 1 , further comprising a power source to provide power to said first receiver and said first transmitter, said power source to comprise a power circuit configured to convert signals from a radio-frequency field to direct current.

9. The apparatus of claim 1 , further comprising: a processor to connect to said first receiver and said first transmitter, said processor to receive said reply signal, qualify said reply signal, and output a data signal representative of said reply signal; and wherein said first transmitter transmits said data signal at said second frequency.

10. The apparatus of claim 9 , wherein said processor comprises one of a digital processor or analog processor, and said data signal comprises a digital data signal or analog data signal, respectively.

11. A system, comprising:

a first transmitter to transmit an interrogation signal within an interrogation zone;

a marker to generate a reply signal in response to said interrogation signal;

a first transponder positioned remotely from said marker which is configured to receive said reply signal at a first frequency, convert said reply signal at said first frequency to said replay signal as a second frequency, and transmit said reply signal at a said second frequency;

a first receiver positioned remotely from said marker which is configured to receive said reply signal at said second frequency, and convert said reply signal to said first frequency; and

a controller to detect said marker within said interrogation zone using said reply signal at said first frequency, and output a marker detect signal in accordance with said detection.

12. The system of claim 11 , wherein said first transponder comprises: a second receiver to receive said reply signal from said marker at said first frequency; and a second transmitter to connect to said second receiver, said second transmitter to transmit said reply signal at said second frequency.

13. The system of claim 12 , wherein said first frequency comprises a lower frequency in a range between 50 Hertz to 13 Megahertz, and said second frequency comprises a higher frequency in a range between 13.01 Megahertz to 2.45 Gigahertz.

14. The system of claim 12 , wherein said first frequency comprises a higher frequency in a range between 13.01 Megahertz to 2.45 Gigahertz, and said second frequency comprises a lower frequency in a range between 50 Hertz to 13 Megahertz.

15. The system of claim 12 , wherein said first frequency corresponds to said second frequency.

16. The system of claim 12 , wherein said second receiver comprises an inductor-capacitor antenna.

17. The system of claim 12 , wherein said second transmitter comprises: an amplifier to receive as input said reply signal and output an amplified signal; a local oscillator to provide an oscillation signal; and a mixer to connect to said amplifier and local oscillator, said mixer to receive as input said amplified signal and said oscillation signal and output said reply signal at said second frequency.

18. The system of claim 12 , further comprising a power source to provide power to said second receiver and said second transmitter, said power source to comprise a battery powered circuit.

19. The system of claim 12 , further comprising a power source to provide power to said second receiver and said second transmitter, said power source to comprise a power circuit configured to convert signals from a radio-frequency field to direct current.

20. The system of claim 12 , further comprising a processor to receive as input said reply signals, qualify said reply signals, and output a data signal representative of said reply signals.

21. The system of claim 12 , wherein said processor comprises one of a digital processor or analog processor, and said data signal comprises a digital data signal or analog data signal, respectively.

22. The system of claim 12 , further comprising a second transponder comprising: a third receiver to receive said reply signal from said second transmitter at said second frequency; and a third transmitter to connect to said third receiver, said third transmitter to transmit said reply signal at said first frequency.

23. The system of claim 22 , wherein said second transponder further comprises a processor to receive as input said reply signal, qualify said reply signal, and output a data signal representative of said reply signals.

24. A method, comprising:

transmitting an interrogation signal in an interrogation zone;

generating a reply signal from a marker in response to said interrogation signal;

repeating said reply signal by a transponder positioned remotely from said marker by a receiver configured to receive said reply signal at a first frequency;

convening said reply signal to a second frequency; and

transmitting said reply signal at said second frequency;

receiving said reply signal from said transponder by a receiver configured to receive said reply signal at said second frequency;

convening said reply signal to said first frequency;

sending said reply signal to a controller; and

determining whether said marker is within said interrogation zone in accordance with said reply signal.

25. The method of claim 24 , further comprising: receiving said reply signal at said second frequency by a second transponder; convening said reply signal to said first frequency; and transmitting said reply signal at said first frequency.

26. The method of claim 25 , wherein receiving said reply signal from said transponder comprises: receiving said reply signal at said first frequency; and sending said reply signal to a controller.