Techniques for folded tag antennas
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.
1. An RFID device comprising:
a flexible substrate;
an antenna pattern formed on the flexible substrate, the antenna pattern having a major axis from a distal region to 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 major axis from the proximal region at about a predetermined angle with the major axis; 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 major axis from 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 major axis from a second distal region to a second proximal region; and
a second fold in the flexible substrate disposing the second distal region away from the second major axis 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.
9. 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.
10. The method of claim 9 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.
11. The method of claim 10 further comprising disposing an adhesive layer to the RFID inlay to create an RFID label.
12. 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 major axis from a distal region to 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 major axis from the proximal region at about a predetermined angle; and
an integrated circuit electrically coupled to the antenna pattern.
13. The RFID label of claim 12 wherein the integrated circuit includes 3, 4, 5, or 6 contact pads.
14. 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, wherein the antenna comprises a major axis from a proximal region to a distal region of the antenna;
a fold in the flexible substrate disposing away the distal region of the antenna from the major axis from the proximal region of the antenna at about a predetermined angle with the major axis; and
an integrated circuit electrical y coupled to the antenna.
15. The system of claim 14 wherein the integrated circuit is configured for fluidic self assembly, the integrated circuit being embedded in the flexible substrate.
16. The RFID device of claim 7 wherein the integrated circuit is electrically coupled to the second antenna.