Antenna for RFID device reader, and method of use

• US 7,893,887 B2
• Filed: 03/27/2007
• Issued: 02/22/2011
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation
• Original Assignee: Avery Dennison Corporation
• Inventors: Burns, Gary P., Isabell, Michael J.
• Primary Examiner(s): Le; HoangAnh T
• Application Number:
  US11/691,808
• Publication Number:
  US 20080238683A1
• Time in Patent Office: 1,428 Days
• Field of Search: 343/797, 343/793, 343/799, 343/815, 343/817
• US Class Current: 343/799
• 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 21/0025 Modular arrays
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00

Abstract

An antenna for use with an RFID device reader includes a metallic plate and multiple antenna elements attached to the metallic plate. The antenna elements may consist of two prongs each, with the prongs of each element arrayed in a diagonal configuration, and with the two prongs forming an X-shape. Each of the prongs may include a pair of L-shape prong parts that are coupled together by an electrical element connecting the corners of the L-shape prong parts. The distal ends of all of the prong parts of the antenna elements may together form a substantially square shape. Each of the antenna elements may be coupled to a single conductor, for connection to an RFID reader. The connection may be through a suitable standard coupling, such as a coaxial cable with a suitable connector.

Claims

1. An RFID reader antenna for use with a read-transmit RFID reader, wherein the antenna includes:

a planar metallic back plate;

a pair of antenna elements attached to the back plate, wherein the antenna elements each include a pair of antenna prongs, each of the prongs in turn including a pair of prong parts that are attached to the plate, and a tuned electrical element between the prong parts; and

at least one electrical coupling for connecting the antenna elements to the read-transmit RFID reader;

wherein the antenna provides magnetic coupling at a range greater than 1 wavelength at an RFID frequency.

2. The RFID antenna of claim 1, wherein the antenna provides magnetic coupling at a range of at least 1 meter, at the RFID frequency.

3. The RFID antenna of claim 1, wherein the antenna provides magnetic coupling at a range of between 1 to 2 meters, at the RFID frequency.

4. The RFID antenna of claim 1, wherein the RFID frequency is a frequency from 902 MHz to 928 Mhz.

5. The RFID antenna of claim 1, wherein the RFID frequency is 13.56 MHz.

6. The RFID antenna of claim 1, wherein the electrical element is tunes the antenna to operate at the RFID frequency.

7. The RFID antenna of claim 1, wherein the prongs of each of the antenna elements are diagonally arrayed, with the prongs of the elements together arrayed in an X shape.

8. The RFID antenna of claim 1, wherein the prong parts each have bent ends.

9. The RFID antenna of claim 8, wherein the prong parts each make an angled connection with a central attachment region of the back plate.

10. The RFID antenna of claim 8, wherein the bent ends of the prong parts together form a square shape.

11. The RFID antenna of claim 1, wherein the antenna prongs are made of cast aluminum.

12. The RFID antenna of claim 11, wherein the back plate is made of aluminum.

13. The RFID antenna of claim 1, further comprising a plastic housing enclosing the back plate and the antenna elements.

14. The RFID antenna of claim 1, in combination with a read-transmit RFID reader electrically connected to the RFID antenna via the at least one electrical coupling.

15. A method of RFID reader antenna communication, the method comprising:

sending signals at an RFID frequency through the antenna, from a read transmit RFID reader coupled to the antenna;

wherein the antenna includes;

a planar metallic back plate;

a pair of antenna elements attached to the back plate, wherein the antenna elements each include a pair of antenna prongs, each of the prongs in turn including a pair of prong parts that are attached to the plate, and a tuned electrical element between the prong parts; and

an electrically coupling for connecting the antenna elements to the read-transmit RFID reader; and

wherein the antenna provides magnetic coupling at a range greater than 1 wavelength at the RFID frequency.

16. The method of claim 15, wherein the antenna provides magnetic coupling at a range of at least 1 meter, at the RFID frequency.

17. The method of claim 15, wherein the antenna provides magnetic coupling at a range of between 1 to 2 meters, at the RFID frequency.

18. The method of claim 15, wherein the antenna is tuned for operation at the RFID frequency.

19. The method of claim 15, further comprising receiving signals with the antenna from an RFID device, at the RFID frequency.

20. The method of claim 19, wherein the sending and the receiving art parts of an interactive communication between the RFID reader and the RFID device.