Ultra high frequency radio frequency identification tag

• US 20060044192A1
• Filed: 10/25/2005
• Published: 03/02/2006
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Egbert, William C.
• Granted Patent: US 7,215,295 B2
• Time in Patent Office: Days
• US Class Current: 343/700.MS
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• 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 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 9/265 Open ring dipoles; Circular dipoles

Abstract

An antenna design for radio frequency identification (“RFID”) tags. More particularly, the present invention relates to design for RFID tags particularly operating in the ultra high frequency (“UHF”) operating band.

Claims

1-17. -17. (canceled)

18. :

A radio frequency identification (“

RFID”

) tag, comprising;

a dielectric substrate;

an antenna attached to the dielectric substrate; and

an integrated circuit coupled to the antenna,

wherein the antenna comprises;

i) a dipole antenna element comprising two conductors having lengths that set an operating frequency range of the antenna; and

ii) a second antenna element coupled to the conductors dipole antenna that substantially balances an impedance of the antenna with an input impedance of the integrated circuit without substantially affecting the operating frequency of the antenna.

19. :

The RFID tag of claim 18, wherein phases for imaginary components of the input impedance of the integrated circuit and the input impedance of the antenna are opposite.

20. :

The UHF RFID tag of claim 19, wherein magnitudes of real components and the imaginary components of the input impedance of the integrated circuit and the input impedance of the antenna are equal.

21. :

The RFID tag of claim 18,

wherein the first antenna element includes a first conductor and a second conductor that include meanders, and

wherein a first portion of the second antenna element and a second portion of the second antenna element are in the shape of closed loops or polygons.

22. :

The RFID tag of claim 18, wherein the second antenna element comprises a first portion and a second portion coupled to opposite ends of the dipole antenna.

23. :

The RFID tag of claim 22, wherein the first portion and the second portion of the second antenna element are in the shape of closed loops.

24. :

The RFID tag of claim 22, wherein the first portion and the second portion of the second antenna element are in the shape of polygons.

25. :

The RFID tag of claim 22, wherein the first portion and the second portion of the second antenna element dissimilar in shape.

26. :

The RFID tag of claim 22, wherein the first portion and the second portion of the second antenna element similar in shape.

27. :

The RFID tag of claim 22, wherein the first portion and the second portion of the second antenna element different in size.

28. :

The RFID tag of claim 18, wherein the first conductor and second conductor are made from a wire, patterned conductive foils, or printed conductive traces.

29. :

The RFID tag of claim 18, wherein the dipole antenna element is made from a different conductive material than the second antenna element.

30. :

A method of manufacturing a radio frequency identification (“

RFID”

) tag comprising;

selecting lengths for two conductors of a dipole antenna element for an antenna of the RFID tag to set the operating frequency range for the RFID tag; and

selecting a second antenna element for electrical connection to the dipole antenna element to substantially balance the impedance of the antenna with an input impedance of an integrated circuit of the RFID tag without substantially affecting the operating frequency of the dipole antenna; and

manufacturing the RFID tag according to the selected lengths of the conductors of the dipole antenna element and the selected second antenna element.

31. :

The method of claim 30, wherein selecting a length comprises selecting a length for two conducts of the first antenna element to be in a range of 85 mm. to 170 mm.