Transfer function system for determining an identifier on a surface acoustic wave identification tag and method of operating the same

• US 6,958,696 B2
• Filed: 10/09/2002
• Issued: 10/25/2005
• Est. Priority Date: 10/09/2002
• Status: Expired due to Term

• Current Assignee: RF Saw Components Incorporated
• Original Assignee: RF Saw Components Incorporated
• Inventors: Hartmann, Clinton S., Bellamy, John C.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US10/268,108
• Publication Number:
  US 20040075560A1
• Time in Patent Office: 1,112 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.7, 340/10.1, 340/10.3, 340/10.41, 340/572.2, 340/10.42, 310/313.B, 310/313.C, 310/313.D, 310/313.R, 310/313.A, 235/454, 235/455, 342/42, 342/51, 342/43, 342/50
• US Class Current: 340/572.1
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip
• CPC Class Codes: G08B 13/2422 using acoustic or microwave tags
• CPC Class Codes: G08B 13/2431 Tag circuit details
• CPC Class Codes: G08B 13/2485 Simultaneous detection of multiple EAS tags
• CPC Class Codes: G08B 25/007 Details of data content structure of message packets; data protocols
• CPC Class Codes: H03H 9/6406 Filters characterised by a particular frequency characteristic

Abstract

A transfer function system for determining an identifier on a surface acoustic wave (SAW) identification tag and a method of operating the same. In one embodiment the system provides for (1) generating a radio frequency (RF) interrogation signal that causes a transducer located on a piezoelectric substrate to produce an initial acoustic pulse that reflects off of a plurality of reflectors arranged according to time and phase position on the substrate to yield response acoustic pulses, the transducer generating an RF response signal from the response acoustic pulses; and (2) determining the identifier by decoding the RF response signal in view of predefined time, phase and amplitude parameters.

Claims

1. A system for determining an identifier on a surface acoustic wave (SAW) identification tag, comprising:

generating a radio frequency (RF) interrogation signal that causes a transducer located on a piezoelectric substrate to produce an initial acoustic pulse that reflects off of a plurality of reflectors arranged according to time and phase position on said substrate to yield response acoustic pulses, said transducer generating an RF response signal from said response acoustic pulses;

determining said identifier by decoding said RF response signal in view of predefined time, phase and amplitude parameters.

2. The system as recited in claim 1 wherein said RF interrogation signal has a carrier frequency of about 2.44 GHz.

3. The system as recited in claim 1 further comprising a group of reflector locations on said substrate.

4. The system as recited in claim 3 wherein a plurality of said groups are located on said substrate.

5. The system as recited in claim 4 wherein fourteen of said groups are located on said substrate.

6. The system as recited in claim 5 wherein up to 80 bits of data are encoded on said identification tag.

7. The system as recited in claim 4 wherein nineteen of said groups are located on said substrate.

8. The system as recited in claim 7 wherein up to 112 bits of data are encoded on said identification tag.

9. The system as recited in claim 3 wherein said group is comprised of 21 of said locations having two of said reflectors arranged therein separated by a minimum of ten reflector locations.

10. The system as recited in claim 3 wherein said group is comprised of 16 of said locations having a single reflector arranged therein.

11. A method of operating a system for determining an identifier on a surface acoustic wave (SAW) identification tag, comprising:

causing a radio frequency (RF) interrogation signal to be generated that excites a transducer located on a piezoelectric substrate into producing an initial acoustic pulse that reflects off of a plurality of reflectors arranged according to time and phase position on said substrate to yield response acoustic pulses, said transducer generating an RF response signal from said response acoustic pulses;

detecting said RF response signal and decoding said identifier from said RF response signal in view of predefined time, phase and amplitude parameters.

12. The method as recited in claim 11 wherein said RF interrogation signal has a carrier frequency of about 2.44 GHz.

13. The method as recited in claim 11 further comprising a group of reflector locations on said substrate.

14. The method as recited in claim 13 wherein a plurality of said groups are located on said substrate.

15. The method as recited in claim 14 wherein fourteen of said groups are located on said substrate.

16. The method as recited in claim 15 wherein up to 80 bits of data are encoded on said identification tag.

17. The method as recited in claim 14 wherein nineteen of said groups are located on said substrate.

18. The method as recited in claim 17 wherein up to 112 bits of data are encoded on said identification tag.

19. The method as recited in claim 13 wherein said group is comprised of 21 of said locations having two of said reflectors arranged therein separated by a minimum of ten reflector locations.

20. The method as recited in claim 13 wherein said group is comprised of 16 of said locations having a single reflector arranged therein.