Low profile metal-surface mounted RFID tag antenna

• US 8,169,322 B1
• Filed: 11/07/2008
• Issued: 05/01/2012
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Weber, Robert J., Zhan, Sanyi
• Primary Examiner(s): Previl, Daniel
• Application Number:
  US12/266,913
• Time in Patent Office: 1,271 Days
• Field of Search: 3405721-5729, 340/539.1, 340/568.1, 340/10.1, 340/10.42, 340/10.51
• US Class Current: 340/572.7
• 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 19/07771 the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole

Abstract

A passive RFID tag suitable for attachment to an electrically conductive surface is provided. The passive RFID tag includes a dielectric substrate, an RFID chip for storing data, and an RFID antenna structure operatively connected to the RFID chip wherein the RFID antenna structure comprises a slotted inverted L-shape. A method of manufacturing a passive RFID tag includes forming an antenna structure on a conductive layer, the antenna structure comprising a slotted inverted L-shape. The method further includes operatively connecting an RFID chip with the antenna structure. A method associated with a passive RFID tag includes providing a passive RFID tag. The passive RFID tag includes a dielectric substrate, an RFID chip for storing data, and an RFID antenna structure operatively connected to the RFID chip wherein the RFID antenna structure comprises a slotted inverted L-shape. The method further includes operatively connecting the passive RFID tag to a conductive surface.

Claims

1. A passive RFID tag suitable for attachment to an electrically conductive surface or a non-conductive surface, the passive RFID tag comprising:

a conductive radiation patch with a slotted air gap and a rectangular microstrip line;

a conductive ground patch electrically connected to the conductive radiation patch and suitable for attachment to the electrically conductive surface or the non-conductive surface;

a conductive sidewall connecting the conductive radiation patch and the conductive ground patch;

a dielectric substrate between the conductive radiation patch and the conductive ground patch; and

a surface mounted RFID chip for storing data, the RFID chip surface mounted on the conductive radiation patch.

2. The passive RFID tag of claim 1 wherein the dielectric substrate having a dielectric constant greater than 1.2.

3. The passive RFID tag of claim 1 wherein the dielectric substrate having a dielectric constant between 1.2 and 2.0.

4. The passive RFID tag of claim 1 wherein the dielectric substrate having a dielectric constant greater than 2.0.

5. The passive RFID tag of claim 1 wherein the dielectric substrate comprises foam.

6. The passive RFID tag of claim 1 wherein the dielectric substrate comprises a PTFE composite.

7. The passive RFID tag of claim 1 wherein the conductive radiation patch and the conductive ground patch are on a metal layer folded around the dielectric substrate.

8. The passive RFID tag of claim 7 wherein the metal layer being copper and wherein the RFID antenna structure being formed by silver printing.

9. The passive RFID antenna tag of claim 1 wherein the conductive sidewall and a RFID antenna radiation path form a slotted inverted L-shape.

10. The passive RFID antenna tag of claim 9 wherein the slotted inverted L-shape having dimensions selected to provide an impedance matching an impedance of the RFID chip.

11. The passive RFID tag antenna of claim 1 wherein the conductive sidewall and a RFID antenna radiation path form a slotted inverted L-shape.

12. The passive RFID tag antenna of claim 1 wherein an RFID antenna radiation path of the passive RFID tag antenna has only one radiating slot.

13. The passive RFID tag antenna of claim 1 wherein the passive RFID tag has a thickness of 62 mils or less.

14. A method of manufacturing a passive RFID tag, the method comprising:

forming a radiation patch by printing an antenna pattern on a conductive layer;

folding the conductive layer around a dielectric substrate such that the radiation patch is on a first side of the passive RFID tag and the ground layer is on a second side of the passive RFID tag with the dielectric substrate therebetween and such that a sidewall of the conductive layer connects the radiation patch and the ground layer, with the radiation patch and sidewall forming a slotted inverted L-shape;

surface mounting an RFID chip on the conductive layer.

15. The method of claim 14 wherein the dielectric substrate comprises foam.

16. The method of claim 14 wherein the printing is silver printing.

17. A passive RFID tag suitable for attachment to an electrically conductive surfaces and non-electrically conductive surfaces, the passive RFID tag comprising:

a dielectric substrate;

a conductive layer folded around the dielectric substrate to provide a radiation patch on a first side of the dielectric substrate and a ground patch on an opposite second side of the dielectric substrate and a sidewall connecting the radiation catch and the around patch, the around patch suitable for attachment to electrically conductive surfaces and non-electrically conductive surfaces;

an RFID chip for storing data, the RFID chip surface mounted to the radiation patch;

wherein the sidewall and a RFID antenna radiation path form a slotted inverted L-shape.