RFID tag and method of manufacture

• US 7,274,297 B2
• Filed: 07/01/2004
• Issued: 09/25/2007
• Est. Priority Date: 07/01/2004
• Status: Active Grant

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Martinez, Rene D., Lam, For S., Kodukula, Venkata S. R.
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US10/882,660
• Publication Number:
  US 20060000915A1
• Time in Patent Office: 1,181 Days
• Field of Search: 340/572.1, 340/572.7, 340/572.8, 235/492, 235/487, 235/441, 298/25
• 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 19/07756 the connection being non-galvanic, e.g. capacitive
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

An RFID tag may include an antenna substrate comprising a conductive layer etched or deposited to form an antenna, and a circuit substrate comprising a conductive layer etched or deposited to form a circuit, the antenna electro-magnetically coupled to the circuit. An RFID tag may be formed from an insert substrate comprising an insulative layer between two conductive layers, one of the conductive layers etched to form an antenna and the other conductive layer etched to form a circuit. The insert substrate may be received in an envelope formed by a label substrate, which may carry a pressure sensitive adhesive.

Claims

1. An RFID tag, comprising:

an antenna substrate comprising an insulative layer and a conductive layer, the insulative layer of the antenna substrate comprising a first surface and a second surface opposed to the first surface, the conductive layer of the antenna substrate carried by the second surface of the insulative layer of the antenna substrate, the conductive layer of the antenna substrate patterned to form a slot antenna;

a circuit substrate comprising an insulative layer and a conductive layer, the conductive layer of the circuit substrate patterned to form a circuit including an antenna line, a transformer, and a ground line, each conductively coupled to one another and physically formed in a plane defined by the conductive layer of the circuit substrate; and

a semiconductor device electrically coupled to the circuit, wherein the antenna substrate and circuit substrate are coupled such that at least one portion of the slot antenna is electro-magnetically coupled through the insulative layer of the circuit substrate to at least one portion of the circuit without an electrical current path therebetween, to provide signals between the slot antenna and the semiconductor device.

2. The RFID tag of claim 1 wherein the first surface of the insulative layer of the antenna substrate carries at least one of a human-readable or a machine-readable marking.

3. The RFID tag of claim 1 wherein the conductive layer of the antenna substrate is patterned via etching to form the slot antenna.

4. The RFID tag of claim 1 wherein the conductive layer of the antenna substrate is patterned via depositioning to form the slot antenna.

5. The RFID tag of claim 1 wherein the conductive layer of the circuit substrate is patterned via etching to form the circuit.

6. The RFID tag of claim 1 wherein the conductive layer of the circuit substrate is patterned via depositioning to form the circuit.

7. The RFID tag of clam 1, further comprising:

a pressure sensitive adhesive covering at least a portion of the semiconductor device and circuit; and

a selectively releasable release liner covering at least a portion of the pressure sensitive adhesive.

8. A method of forming an RFID tag, the method comprising:

providing an antenna substrate comprising a label stock and a conductive layer, the label stock of the antenna substrate comprising a first surface and a second surface opposed to the first surface, the conductive layer of the antenna substrate having a first area and carried by the second surface of the label stock of the antenna substrate;

providing a circuit substrate comprising an insulative layer and a conductive layer, the conductive layer of the circuit substrate having a second area, where the second area is substantially smaller than the first area;

etching the conductive layer of the antenna substrate to form a slot antenna;

etching the conductive layer of the circuit substrate to form a circuit having at least two of an antenna line, a transformer, an inductor, or a ground line, formed in a plane defined by the conductive layer of the circuit substrate;

electrically coupling a semiconductor device to the circuit; and

physically coupling the antenna substrate and circuit substrate to provide signals between the slot antenna and the semiconductor device, wherein physically coupling the antenna substrate and circuit substrate to provide signals between the slot antenna and the semiconductor device, comprises positioning the antenna substrate and the circuit substrate such that at least a portion of the slot antenna is electro-magnetically coupled through the insulative layer of the circuit substrate to at least a portion of the circuit without any through-holes in the insulative layer.

9. The method of claim 8 wherein the conductive layer of the antenna substrate covers substantially all of the second surface of the label stock of the antenna substrate.

10. The method of claim 9 wherein the conductive layer of the circuit covers substantially less than all of the insulative layer of the circuit substrate.

11. An RFID tag, comprising:

an insert substrate comprising a first conductive layer, a second conductive layer and an insulative layer between the first and the second conductive layers, where the first conductive layer is patterned as a slot antenna and the second conductive layer is patterned as a circuit having at least two of an antenna line, a transformer, an inductor, or a ground line, formed in a plane defined by the second conductive layer, at least a portion of the slot antenna electro-magnetically coupled to at least a portion of the circuit without an electrical current path therebetween to transfer signals between the slot antenna and the circuit; and

a semiconductor device electrically coupled to the circuit to transfer signals between the semiconductor device and the circuit.

12. The RFID tag of claim 11 wherein the insulative layer is solid, having no apertures extending therethrough.

13. The RFID tag of claim 11, further comprising:

a package substrate forming an envelope, wherein the insert substrate is received within the envelope.

14. The RFID tag of claim 11, further comprising:

an adhesive carried by at least a portion of the package substrate.

15. An RFID tag, comprising:

an electrically conductive circuit trace having at least two of an antenna line, a transformer, an inductor, or a ground line, formed in a plane defined by the circuit trace;

an electrically conductive slot antenna, the slot antenna spaced from the circuit trace and electrically insulated therefrom, at least a portion of the slot antenna electro-magnetically coupled to at least a portion of the circuit trace without an electrically conductive current path therebetween to transfer signals between the slot antenna and the circuit trace; and

a semiconductor device electrically coupled to the circuit trace to transfer signals between the semiconductor device and the slot antenna via the circuit trace.

16. The RFID tag of claim 15 wherein the slot antenna is spaced from the circuit trace by at least one insulative layer.

17. The RFID tag of claim 15 wherein the slot antenna is spaced from the circuit trace by air.