Chipless RFID tag using hybrid coding
Embodiments described herein include a chipless patterned conductor, comprising one or more glyphs. Each glyph comprises a disk and a ring structure including at least one ring surrounding the disk. One or more of a spacing between the disk and the at least one ring and a width of the at least one ring is configured to determine a characteristic resonant frequency of the glyph. At least one notch is disposed in at least one of the disk and at least one ring of the ring structure. The at least one notch is configured such that the magnitude of resonances in the glyph are dependent on polarization direction.
1. A chipless patterned conductor, comprising:
one or more glyphs, each glyph comprising:
a disk;
a ring structure comprising at least one ring surrounding the disk, the at least one ring comprising a first ring surrounding the disk and a second ring surrounding the disk, the second ring configured to serve as a counter electrode for the first ring and the disk, wherein one or more of a spacing between the disk and the at least one ring and a width of the at least one ring is configured to determine a characteristic resonant frequency of the glyph; and
at least one notch in at least one of the disk and at least one ring of the ring structure, the at least one notch configured such that the magnitude of resonances in the glyph are dependent on polarization direction.
2. The chipless patterned conductor of claim 1 , wherein the ring structure is configured to resonate in a band of about 40 GHz to about 75-110 GHz.
3. The chipless patterned conductor of claim 1 , wherein a width of the first ring is different than a width of the second ring.
4. The chipless patterned conductor of claim 1 , wherein a width of the first ring is substantially the same as the width of the second ring.
5. The chipless patterned conductor of claim 1 , wherein a spacing between the first ring and the disk is different than a spacing between the second ring and the disk.
6. The chipless patterned conductor of claim 1 , wherein the disk has two notches.
7. The chipless patterned conductor of claim 6 , wherein the two notches are on opposite sides of the disk.
8. The chipless patterned conductor of claim 1 , further comprising:
a ground plane; and
a dielectric layer disposed between the one or more glyphs and the ground plane.
9. The chipless patterned conductor of claim 1 , wherein the one or more glyphs comprises a plurality of glyphs.
10. The chipless patterned conductor of claim 9 , wherein a first glyph of the plurality of glyphs has one or more of first ring configuration and a first notch configuration and the second glyph of the plurality of glyphs has one or more of a second ring configuration different than the first ring configurations and a second notch configuration different than the first notch configuration.
11. The chipless patterned conductor of claim 1 , wherein the at least one notch is disposed in the second ring.
12. A method of forming a chipless patterned conductor, comprising:
forming at least one glyph from a conductive foil, comprising:
forming a disk;
forming a ring structure comprising least one ring surrounding the disk, wherein one or more of a spacing between the disk and the at least one ring and a width of the at least one ring is configured to determine a characteristic resonant frequency of the glyph;
forming at least one notch in at least one of the disk and at least one ring of the ring structure, the at least one notch configured such that the magnitude of resonances in the glyph are dependent on polarization direction; and
transferring the at least one glyph to a substrate having a first side and an opposite second side and a conductive layer disposed on the second side of the substrate, wherein the at least one glyph is transferred to the first side of the substrate.
13. The method of claim 12 , further comprising forming the at least one glyph on a substrate and transferring the at least one glyph to an object.
14. The method of claim 12 , wherein forming the at least one glyph comprises forming the at least one glyph directly on an object.
15. The method of claim 12 , wherein forming the at least one glyph comprises printing the at least one glyph from a conductive material.
16. The method of claim 12 , wherein forming the at least one glyph comprises forming the at least one glyph from a conductive foil.
17. The method of claim 12 , wherein the substrate has a first side and an opposite second side and the at least one glyph comprises a first glyph and a second glyph, wherein the first glyph is disposed on the first side of the substrate and the second glyph is disposed on the second side of the substrate.
18. The method of claim 17 , wherein the substrate comprises a first substrate layer and a second substrate layer and a conductive layer is disposed between the first substrate layer and the second substrate layer.
19. The method of claim 12 , further comprising:
depositing a conductive ground plane on the substrate;
depositing a dielectric layer on the conductive ground plane; and
forming the at least one glyph on the dielectric layer.
20. A system for reading a patterned conductor comprising:
a transmitter configured to transmit an electromagnetic radiation signal towards the patterned conductor, the patterned conductor comprising one or more glyphs each glyph comprising:
a disk;
a ring structure comprising at least one ring surrounding the disk, the at least one ring comprising a first ring surrounding the disk and a second ring surrounding the disk, the second ring configured to serve as a counter electrode for the first ring and the disk, wherein one or more of a spacing between the disk and the at least one ring and a width of the at least one ring is configured to determine a characteristic resonant frequency of the glyph; and
at least one notch in at least one of the disk and at least one ring of the ring structure, the at least one notch configured such that the magnitude of resonances in the glyph are dependent on polarization direction, wherein each glyph is configured to backscatter at least a portion of the electromagnetic radiation based on the characteristic resonant frequency and the magnitude of resonances;
a receiver configured to receive a backscattered signal; and
a processor configured to associate the backscattered signal with a digital signature.