Techniques for folded tag antennas

• US 20070046475A1
• Filed: 08/29/2006
• Published: 03/01/2007
• Est. Priority Date: 09/01/2005
• Status: Active Grant

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Alien Technology Corporation
• Inventors: Carrender, Curtis
• Granted Patent: US 7,598,867 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: G06K 19/0779 the antenna being foldable or folded
• CPC Class Codes: G08B 13/24 by interference with electromagnetic field distribution
• CPC Class Codes: H01Q 1/20 Resilient mountings
• 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 9/24 Shunt feed arrangements to single active elements, e.g. for delta matching
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00
• CPC Class Codes: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407

Abstract

Techniques for an RFID device with improved multi-axis performance are provided. The device includes a flexible substrate with an antenna pattern formed thereon. A fold in the flexible substrate results in the antenna pattern crossing over itself and disposes a distal region of the antenna pattern away from a proximal region at about a predetermined angle. An integrated circuit is electrically coupled to the antenna pattern. In a specific embodiment, the antenna pattern is slit along a major axis to allow folding a segment of an antenna pattern.

Claims

1. An RFID device comprising:

a flexible substrate;

an antenna pattern formed on the flexible substrate, the antenna pattern having a distal region and a proximal region;

a fold in the flexible substrate whereby the antenna pattern crosses over itself, the fold disposing the distal region away from the proximal region at about a predetermined angle; and

an integrated circuit electrically coupled to the antenna pattern.

2. The RFID device of claim 1 wherein the predetermined angle ranges from about 45 degrees to about 135 degrees.

3. The RFID device of claim 1 wherein the distal region is orthogonal to the proximal region.

4. The RFID device of claim 1 wherein a length is defined by a distal end and a proximal end of the antenna pattern, the length ranging from about 1 inch to about 3 inches.

5. The RFID device of claim 4 wherein the RFID device is configured to receive radio frequency signals within about 902 MHz to about 928 MHz, and the length ranges from about 1% to about 100% of a wavelength of the received radio frequency signals.

6. The RFID device of claim 1 wherein the antenna pattern is configured to have improved RF multi-axis performance in a folded arrangement relative to an unfolded arrangement.

7. The RFID device of claim 1 further comprising:

a second antenna pattern formed on the flexible substrate, the second antenna pattern having a second distal region and a second proximal region; and

a second fold in the flexible substrate disposing the second distal region away from the second proximal region at about a second predetermined angle.

8. The RFID device of claim 7 wherein the second predetermined angle is about the same as the first predetermined angle.

25. The RFID device of claim 7 wherein the integrated circuit is electrically coupled to the second antenna.

9. A method for manufacturing an RFID tag, the method comprising:

providing a substantially planar substrate;

forming a first antenna pattern thereon, the first antenna pattern extending in a first direction from a distal end to a proximal end;

electrically coupling the first antenna pattern to an integrated circuit;

determining at least one fold position in the first antenna pattern; and

after the forming of the first antenna pattern, automatically folding the flexible substrate at about the at least one fold position to dispose in a second direction the distal end of the first antenna pattern from the at least one fold position in the first antenna pattern, the second direction differing from the first direction.

10. The method of claim 9 wherein the first direction is orthogonal to second direction.

11. The method of claim 9 wherein the first direction ranges from about 45 degrees to about 135 degrees from the second direction.

12. The method of claim 9 wherein the at least one fold position in the first antenna pattern is located at about a midpoint of the first antenna pattern in the first direction.

13. The method of claim 9 wherein the at least one fold position in the first antenna to the proximal end of the first antenna pattern ranges from 20% to 80% of a length of the first antenna pattern in the first direction.

14. The method of claim 9 wherein the flexible substrate includes a second antenna pattern thereon, the second antenna pattern extending from a distal end to a proximal end in a third direction.

15. The method of claim 14 further comprising:

determining at least one fold position in the second antenna pattern;

automatically folding the flexible substrate at about the at least one fold position in the second antenna pattern to dispose in a fourth direction the distal end of the second antenna pattern from the at least one fold position in the second antenna, the fourth direction differing from the third direction; and

coupling the second antenna pattern to the integrated circuit.

16. The method of claim 15 wherein the third direction is orthogonal to fourth direction.

17. The method of claim 15 wherein the third direction ranges from about 45 degrees to about 135 degrees from the fourth direction.

18. A method for manufacturing an RFID tag, the method comprising:

providing a web comprising a plurality of RFID inlays, each of the plurality of RFID inlays including;

an antenna, the antenna having a major axis from a first end to a second end, and

an integrated circuit electrically coupled to the antenna;

slitting at the first end along the major axis each antenna to form a partly detached first antenna portion;

singulating the plurality of RFID inlays;

folding the first antenna portion of each antenna.

19. The method of claim 18 further comprising slitting at the second end along the major axis each antenna to form a partly detached second antenna portion;

and folding the second antenna portion of each antenna.

20. The method of claim 19 further comprising disposing an adhesive layer to the RFID inlay to create an RFID label.

21. An RFID label comprising:

a facestock layer;

an adhesive layer; and

an RFID inlay comprising;

a flexible substrate;

an antenna pattern formed on the flexible substrate, the antenna pattern having a distal region and a proximal region;

a fold in the flexible substrate whereby the antenna pattern crosses over itself, the fold disposing the distal region away from the proximal region at about a predetermined angle; and

an integrated circuit electrically coupled to the antenna pattern.

22. The RFID label of claim 21 wherein the integrated circuit includes 3, 4, 5, or 6 contact pads.

23. A system comprising:

an interrogator to transmit an interrogating RF signal, the interrogator including an antenna and transceiver; and

a tag storing identifier information, the tag including;

an antenna formed on a flexible substrate,

a fold in the flexible substrate disposing away a distal region of the antenna from a proximal region of the antenna at about a predetermined angle; and

an integrated circuit electrically coupled to the antenna.

24. The system of claim 23 wherein the integrated circuit is configured for fluidic self assembly, the integrated circuit being embedded in the flexible substrate.