RFID SYSTEM

• US 20090289796A1
• Filed: 05/20/2009
• Published: 11/26/2009
• Est. Priority Date: 05/20/2008
• Status: Active Grant

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Blumberg, David JR.
• Granted Patent: US 8,610,577 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 7/005 with variable reactance for tuning the antenna
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence

Abstract

A magnetic field focusing assembly includes a magnetic field generating device configured to generate a magnetic field, and a split ring resonator assembly configured to be magnetically coupled to the magnetic field generating device and configured to focus the magnetic field produced by the magnetic field generating device.

Claims

1. An RFID antenna assembly configured to be energized with a carrier signal, the RFID antenna assembly comprising:

an inductive component including a loop antenna assembly, wherein the circumference of the loop antenna assembly is no more than 25% of the wavelength of the carrier signal; and

at least one capacitive component coupled to the inductive component.

2. The RFID antenna assembly of claim 1 wherein the inductive component is configured to be positioned proximate a first slot assembly to detect the presence of a first RFID tag assembly within the first slot assembly and not detect the presence of a second RFID tag assembly within a second slot assembly that is adjacent to the first slot assembly.

3. The RFID antenna assembly of claim 1 wherein the circumference of the loop antenna assembly is approximately 10% of the wavelength of the carrier signal.

4. The RFID antenna assembly of claim 1 wherein the at least one capacitive component includes a first capacitive component configured to couple a port on which the carrier signal is received and a ground.

5. The RFID antenna assembly of claim 4 wherein the at least one capacitive component includes a second capacitive component configured to couple the port on which the carrier signal is received and the inductive component.

6. An RFID antenna assembly configured to be energized with a carrier signal, the RFID antenna assembly comprising:

an inductive component including a multi-segment loop antenna assembly, wherein the multi-segment loop antenna assembly includes;

at least a first antenna segment including at least a first phase shift element configured to reduce the phase shift of the carrier signal within the at least a first antenna segment, and

at least a second antenna segment including at least a second phase shift element configured to reduce the phase shift of the carrier signal within the at least a second antenna segment,

wherein the length of each antenna segment is no more than 25% of the wavelength of the carrier signal; and

at least one matching component configured to adjust the impedance of the multi-segment loop antenna assembly;

7. The RFID antenna assembly of claim 6 wherein the inductive component is configured to be positioned proximate an access assembly and to allow RFID-based actuation of the access assembly.

8. The RFID antenna assembly of claim 6 wherein at least one of the first phase shift element and the second phase shift element includes a capacitive component.

9. The RFID antenna assembly of claim 6 wherein the length of each antenna segment is approximately 10% of the wavelength of the carrier signal.

10. The RFID antenna assembly of claim 6 wherein the at least one matching component includes:

a first matching component configured to couple a port on which the carrier signal is received and a ground.

11. The RFID antenna assembly of claim 10 wherein the first matching component includes a capacitive component.

12. The RFID antenna assembly of claim 10 wherein the at least one matching component includes:

a second matching component configured to couple the port on which the carrier signal is received and the inductive component.

13. The RFID antenna assembly of claim 12 wherein the second matching component includes a capacitive component.

14. A magnetic field focusing assembly comprising:

a magnetic field generating device configured to generate a magnetic field; and

a split ring resonator assembly configured to be magnetically coupled to the magnetic field generating device and configured to focus at least a portion of the magnetic field produced by the magnetic field generating device.

15. The magnetic field focusing assembly of claim 14 wherein the magnetic field generating device includes an antenna assembly.

16. The magnetic field focusing assembly of claim 14 wherein the split ring resonator assembly is constructed of a metamaterial.

17. The magnetic field focusing assembly of claim 14 wherein the split ring resonator assembly is constructed of a non-ferrous material.

18. The magnetic field focusing assembly of claim 14 wherein the split ring resonator assembly is configured to be generally planar and have a geometric shape.

19. The magnetic field focusing assembly of claim 14 wherein the magnetic field generating device is configured to be energized by a carrier signal having a defined frequency and the split ring resonator assembly is configured to have a resonant frequency that is approximately 5-10% higher than the defined frequency of the carrier signal.

20. The magnetic field focusing assembly of claim 14 wherein the magnetic field generating device is configured to be energized with a carrier signal, the magnetic field generating device including:

an inductive component including a loop antenna assembly, wherein the circumference of the loop antenna assembly is no more than 25% of the wavelength of the carrier signal; and

at least one capacitive component coupled to the inductive component.

21. The magnetic field focusing assembly of claim 20 wherein the inductive component is configured to be positioned proximate a first slot assembly to detect the presence of a first RFID tag assembly within the first slot assembly and not detect the presence of a second RFID tag assembly within a second slot assembly that is adjacent to the first slot assembly.

22. The magnetic field focusing assembly of claim 20 wherein the circumference of the loop antenna assembly is approximately 10% of the wavelength of the carrier signal.

23. The magnetic field focusing assembly of claim 20 wherein the at least one capacitive component includes a first capacitive component configured to couple a port on which the carrier signal is received and a ground.

24. The magnetic field focusing assembly of claim 23 wherein the at least one capacitive component includes a second capacitive component configured to couple the port on which the carrier signal is received and the inductive component.

25. The magnetic field focusing assembly of claim 14 wherein the magnetic field generating device is configured to be energized with a carrier signal, the magnetic field generating device including:

an inductive component including a multi-segment loop antenna assembly, wherein the multi-segment loop antenna assembly includes;

at least a first antenna segment including at least a first phase shift element configured to reduce the phase shift of the carrier signal within the at least a first antenna segment, and

at least a second antenna segment including at least a second phase shift element configured to reduce the phase shift of the carrier signal within the at least a second antenna segment,

wherein the length of each antenna segment is no more than 25% of the wavelength of the carrier signal; and

at least one matching component configured to adjust the impedance of the multi-segment loop antenna assembly;

26. The magnetic field focusing assembly of claim 25 wherein the inductive component is configured to be positioned proximate an access assembly and to allow RFID-based actuation of the access assembly.

27. The magnetic field focusing assembly of claim 25 wherein at least one of the first phase shift element and the second phase shift element includes a capacitive component.

28. The magnetic field focusing assembly of claim 20 wherein the length of each antenna segment is approximately 10% of the wavelength of the carrier signal.

29. The magnetic field focusing assembly of claim 25 wherein the at least one matching component includes:

a first matching component configured to couple a port on which the carrier signal is received and a ground.

30. The magnetic field focusing assembly of claim 29 wherein the first matching component includes a capacitive component.

31. The magnetic field focusing assembly of claim 29 wherein the at least one matching component includes:

a second matching component configured to couple the port on which the carrier signal is received and the inductive component.

32. The magnetic field focusing assembly of claim 31 wherein the second matching component includes a capacitive component.

33. An RFID antenna assembly configured to be energized with a carrier signal, the RFID antenna assembly comprising:

an inductive component including a multi-segment loop antenna assembly, wherein the multi-segment loop antenna assembly includes;

at least a first antenna segment including at least a first phase shift element configured to reduce the phase shift of the carrier signal within the at least a first antenna segment, and

at least a second antenna segment including at least a second phase shift element configured to reduce the phase shift of the carrier signal within the at least a second antenna segment,

at least one far field antenna assembly;

wherein the length of each antenna segment is no more than 25% of the wavelength of the carrier signal; and

at least one matching component configured to adjust the impedance of the multi-segment loop antenna assembly.

34. The RFID antenna assembly of claim 33 wherein the inductive component is configured to be positioned proximate an access assembly of a processing system and to allow RFID-based actuation of the access assembly.

35. The RFID antenna assembly of claim 33 wherein the far field antenna assembly is a dipole antenna assembly.

36. The RFID antenna assembly of claim 33 wherein the far field antenna assembly includes a first antenna portion and a second antenna portion.

37. The RFID antenna assembly of claim 36 wherein the sum length of the first antenna portion and the second antenna portion is greater than 25% of the wavelength of the carrier signal.