Inductively coupled extension antenna for a radio frequency identification reader

• US 20090015383A1
• Filed: 07/10/2007
• Published: 01/15/2009
• Est. Priority Date: 07/10/2007
• Status: Active Grant

• Current Assignee: Allflex USA Incorporated (Merck & Co., Inc.)
• Original Assignee: Allflex USA Incorporated (Merck & Co., Inc.)
• Inventors: Stewart, Robert
• Granted Patent: US 7,764,177 B2
• Time in Patent Office: Days
• US Class Current: 340/10.300
• CPC Class Codes: G06K 7/10178 including auxiliary means for focusing, repeating or boosting the electromagnetic interrogation field comparable booster antennas integrated on the record carrier itself G06K19/07794
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/48 Transceivers

Abstract

Systems and methods are described for adapting a portable RFID reader to create a portable RFID reader assembly that includes an extension antenna. In many embodiments, the extension antenna can be added to increase the reach of the portable RFID reader. The extension antenna is inductively coupled to the portable RFID reader and in many embodiments, the extension antenna is retrofit to an existing portable RFID reader. In other embodiments, a portable RFID reader and one or more extension antennas are produced as part of a set. One embodiment of the invention includes a reader having reader circuitry configured to generate an activation signal, a first antenna, where the first antenna is electrically connected to the reader circuitry, a reader housing containing the reader circuitry, an extension antenna including an elongated housing, a second antenna located at one end of the housing, and a third antenna located at the opposite end of the housing, where the second antenna is electrically connected to the third antenna. In addition, the first antenna and second antenna are inductively coupled.

Claims

1. A radio frequency identification reader assembly, comprising:

a reader, including;

reader circuitry configured to generate an activation signal;

a first antenna, where the first antenna is electrically connected to the reader circuitry; and

a reader housing containing the reader circuitry; and

an extension antenna including;

an elongated housing;

a second antenna located at one end of the housing; and

a third antenna located at the opposite end of the housing, where the second antenna is electrically connected to the third antenna;

wherein the first antenna and second antenna are inductively coupled.

2. The radio frequency identification reader assembly of claim 1, wherein the reader circuitry is configured to generate an activation signal that causes the first antenna to generate a time varying magnetic field.

4. The radio frequency identification reader assembly of claim 2, wherein:

the first antenna and the second antenna are configured so that the second antenna generates a time varying electrical signal on the electrical connection between the second antenna and the third antenna that is indicative of a time varying magnetic field generated by the first antenna; and

the third antenna is configured to generate a time varying magnetic field indicative of a time varying electrical signal received via the electrical connection between the second antenna and the third antenna.

5. The radio frequency identification reader assembly of claim 1, wherein the third antenna is configured to receive information data from an electronic identification tag.

6. The radio frequency identification reader assembly of claim 5, wherein:

the third antenna is configured to generate an electrical signal indicative of the received information data and to provide the electrical signal to the second antenna via the electrical connection between the third antenna and the second antenna;

the second antenna is configured to generate a magnetic field indicative of an electrical signal generated by the third antenna;

the first antenna is configured to generate an electrical signal indicative of the magnetic field generated by the second antenna and to provide the electrical signal to the reader circuitry via the electrical connection between the first antenna and the reader circuitry; and

the reader circuitry is configured to determine the received information data from the electrical signal received from the first antenna.

7. The radio frequency identification reader assembly of claim 1, wherein at least one of the antennas is a ferrite antenna.

10. The radio frequency identification reader assembly of claim 1, wherein all, of the antennas are ferrite antennas.

11. The radio frequency identification reader assembly of claim 10, wherein all of the ferrite antennas include a circular geometry, have the same cross-section geometry and include the same number of turns.

12. The radio frequency identification reader assembly of claim 1, wherein at least one of the antennas is an air core antenna.

13. The radio frequency identification reader assembly of claim 1, wherein the inductor within at least one of the antennas is connected in parallel with a capacitor.

14. The radio frequency identification reader assembly of claim 1, wherein the electrical, connection between the second antenna and the third antenna includes at beast two electrical conductors.

15. The radio frequency identification reader assembly of claim 1, wherein the elongated housing is constructed from a non-metallic material.

16. The radio frequency identification reader assembly of claim 1, further comprising a mechanical joining mechanism that connects the extension antenna to the reader and aligns the first inductor and the second inductor.

17. The radio frequency identification reader assembly of claim 16, wherein:

the first antenna and second antenna have circular cross sections;

the housing of the reader includes a circular portion axially aligned with the circular cross section of the first antenna;

the elongated housing has a circular cross section;

the circular cross section of the second antenna and the elongated housing are axially aligned; and

the mechanical joining mechanism is configured to attach to the circular portion of the reader housing and to the elongated housing so that that first and second antennas are axially aligned.

18. The radio frequency identification reader assembly of claim 16, wherein the mechanical joining mechanism, comprises:

a coupling sleeve configured to engage the elongated housing of the extension antenna;

a split collar configured to engage the housing of the portable reader; and

a cinching band configured to tighten the split collar.

19. The radio frequency identification reader assembly of claim 16, wherein the mechanical joining mechanism is integral with the elongated housing of the extension antenna.

20. The radio frequency identification reader assembly of claim 16, wherein the mechanical joining mechanism is integral with the housing of the portable reader.

21. The radio frequency identification reader assembly of claim 16, further comprising a handle connected to the mechanical joining mechanism.

22. The radio frequency identification reader assembly of claim 1, wherein the reader housing contains the ferrite antenna.

3. (canceled)

8-9. -9. (canceled)

23. (canceled)

24. An extension antenna, comprising:

a first resonant antenna circuit;

a second resonant antenna circuit;

an electrical interconnection between the first and second resonant antenna circuits; and

an elongated housing containing the first and second antenna circuits and the electrical interconnection;

wherein the first resonant antenna circuit is located at one end of the elongated housing; and

wherein the second resonant antenna circuit is located at the opposite end of the elongated housing.

25. The extension antenna of claim 24, wherein the first and second resonant antenna circuits include ferrite antennas.

26. The extension antenna of claim 25, wherein the first and second resonant antenna circuits include the same inductors, the same capacitors, and the same inductor and capacitor wiring configuration.

27. The extension antenna of claim 26, wherein:

the first and second resonant antenna circuits include antennas that have a circular cross-section geometry; and

the elongated housing has a circular cross-section geometry.

28. A method of activating an electronic identification tag, comprising:

generating a time varying electrical signal;

generating a time varying magnetic field indicative of the time varying electrical signal;

detecting the time varying magnetic field;

generating a second time varying electrical signal indicative of the detected magnetic field;

generating a second time varying magnetic field indicative of the second time varying electrical signal; and

activating the electronic identification tag using the second time varying magnetic field.

29. A method of obtaining identification data from an activated electronic identification tag, comprising:

detecting a magnetic field indicative of the identification data;

generating an electrical signal indicative of the detected magnetic field;

generating a second magnetic field that is indicative of the electrical signal;

detecting the second magnetic field;

generating a second electrical signal indicative of the detected second magnetic field; and

extracting the identification data from the second electrical signal.