COMBINATION RADIO FREQUENCY IDENTIFICATION TRANSPONDER (RFID TAG) AND MAGNETIC ELECTRONIC ARTICLE SUVEILLANCE (EAS) TAG

Abstract: A combination of a radio frequency identification transponder (RFID Tag) and to a magnetic electronic article surveillance (EAS) device is disclosed. The present invention relates generally to a radio frequency identification (RFID) systems, and more specifically to RFID transponders for use in RFID systems and the method for their assembly.

Description: COMBINATION RADIO FREQUENCY IDENTIFICATION TRANSPONDER (RFID TAG) AND MAGNETIC ELECTRONIC ARTICLE SURVEILLANCE (EAS) TAG Cross-Reference to Related Applications The present application claims the benefit under 35 U.S.C. § 120 of U.S. Application N 2 . 09/071,413, filed May 1, 1998. The present application also claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application N 2 60/102,476, filed on September 30, 1998. The present application also claims the benefit under 35 U.S.C. § 119(e) of U.S. Application N° 60/093,088 filed on July 16, 1998. Said applications are herein incorporated by reference in their entirety. Incorporation by Reference The following US Patents and Patent Applications are hereby incorporated herein by reference in their entirety: U.S. Patents Patent No. Issue Date Filing Date Attorney Docket No. 5,521,601 05/28/96 04/21/95 YO995-0088 5,528,222 06/18/96 09/09/94 YO994-180 5,538,803 07/23/96 11/23/94 YO994-0073 5,550,547 08/27/96 09/12/94 YO994-185 5,552,778 09/03/96 11/23/94 YO994-0232 5,554,974 09/10/96 11/23/94 YO994-0071 5,563,583 10/08/96 11/23/94 YO994-070 5,565,847 10/15/96 11/23/94 YO994-0072 5,606,323 02/25/97 08/31/95 YO995-157 5,635,693 06/03/97 02/02/95 YO994-0215 5,673,037 09/30/97 09/09/94 YO994-184 5,680,106 10/21/97 10/27/95 YO995-0219 5,682,143 10/28/97 09/09/94 YO994-170 5,729,201 03/17/98 06/29/95 YO995-109 5,729,697 03/17/98 04/24/95 YO995-076 Patent No. Issue Date Filing Date Attorney Docket No. 5,736,929 04/07/98 06/07/96 YO996-085 5,739,754 04/14/98 07/29/96 YO996-115 5,767,789 06/16/98 08/31/95 YO994-213 5,682,143 10/28/97 09/09/94 YO994-170 5,729,201 03/17/98 06/29/95 YO995-109 5,729,697 03/17/98 04/24/95 YO995-076 5,736,929 04/07/98 06/07/96 YO996-085 5,739,754 04/14/98 07/29/96 YO996-115 5,767,789 06/16/98 08/31/95 YO994-213 5,777,561 07/07/98 09/30/96 YO996-178 5,786,626 07/28/98 03/25/96 YO996-031 5,812,065 09/22/98 12/08/95 YO995-124X 5,821,859 10/13/98 U.S. Nonprovisional Patent A plications 5,729,697 03/17/98 04/24/95 YO995-076 5,736,929 04/07/98 06/07/96 YO996-085 5,777,561 07/07/98 09/30/96 YO996-178 U. S. Nonprovisional Patent Applications Application No. Filing Date Attorney Docket No. 08/681,741 07/29/96 YO996-037 08/660,249 06/07/96 YO996-084 (allowed 4-28-98) 08/621,784 03/25/96 YO996-031 08/626,820 04/03/96 YO995-158 08/646,539 05/08/96 YO996-068 08/681,741 07/29/96 YO996-037 08/694,606 08/09/996 YO995-218 08/790,639 01/29/97 YO997-024 08/790,640 01/29/97 YO997-023 08/733,684 10/17/96 YO996-195 08/862,149 05/23/97 YO997-116 08/862,912 05/23/97 YO997-115 08/862,913 05/23/97 YO997-114 08/909,719 08/12/97 YO995-109B (allowed) 08/935,989 10/23/97 YO997-310 US. Provisional Patent Applications Application No. Filing Date Attorney Docket No. 60/073,102 01/30/98 YO897-0028P1 60/074,605 02/13/98 YO897-0259P1 60/077,879 03/13/98 YO997-0038P1 60/078,287 03/17/98 YO897-0661P1 60/091,350 07/01/98 YO897-0259P2 60/078,304 03/17/98 YO897-0662P1 Application No. Filing Date Attorney Docket No. 60/093,088 07/16/98 38384P1 The following further documents are also incorporated herein by reference in their entirety: IBM Technical Disclosure Bulletin IBM Technical Disclosure Bulletin: Vol. 38 No. 08, August 1995, page 17, "Multifunction Credit Card Package," by Brady, Moskowitz, and Murphy. Literature Reference D. Friedman, H. Heinrich, D. Duan, "A low-power CMOS integrated circuit for field-powered radio frequency identification (RFID) tags," 1997 Digest of Technical Papers of the IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, CA, February 1997. PCT Published International Applications Application No. Filing Date Attorney Docket No. PCT/GB96/00061 01/15/96 UK 9-94-066 PCT PCT/EP95/03703 10/20/95 YO994-242 PCT UK Published Application Application No. Filing Date Attorney Docket No. 9710025.9 05/19/97 YO9-96-084 FIELD OF THE INVENTION The present invention relates to an identification tag and more particularly to an identification tag having a large number of bits of information, where the identification tag has an electronic article surveillance function which is difficult to defeat. DESCRIPTION OF THE RELATED ART Radio frequency identification transponders (RFID Tags) have been developed in the last years to take advantage of the fall in semiconductor logic and memory prices. Such tags are available having a single silicon chip attached to a wire or patch antenna. Such tags, however, may be shielded from the high frequency RF used to communicate with the tags. The anti-theft properties of RFID tags are suspect. Magnetic electronic article surveillance (EAS) tags are much less easily shielded from the low frequency magnetic detection fields. Such EAS tags as described below, however, have possibilities of storing only a few bits of information. Some conventional magnetic EAS tags have employed the Barkhausen jump effect. Generally, the Barkhausen effect is characterized by a tendency for magnetization induced in a magnetic material to change in discrete steps as an external magnetic field is increased or decreased. (The material is said to be a non-linear magnetic material if the magnetisation of the material is not proportional to the external magnetic field.) A large temporal flux change, df./dt, occurs when such a step takes place, and a sizable voltage may be induced in a sensing or pickup coil. For example, U.S. Pat. No. 5,181,020 describes a thin-film magnetic tag having a magnetic thin film formed on a polymer substrate and a method for producing the same. The thin film exhibits a large Barkhausen discontinuity without intentional application of external torsional or tensile stress on use. A particular disclosed use is as a marker or tag for use in an article surveillance system wherein articles may be identified by interrogating the tagged article in a cyclic magnetic field of a predetermined frequency in a surveillance area and detecting a harmonic wave of the magnetic field generated by the tag in the surveillance area. This conventional system is only a single bit element using a single Barkhausen layer with no ability to develop a code to distinguish items. U.S. Pat. No. 5,313,192 describes another single bit tag which relies on the Barkhausen effect. The tag of this invention is selected to include a first component comprised of a soft magnetic material which constitutes the bulk of the tag. A second component comprised of a semi-hard or hard magnetic material is integral with the first component. The tag is conditioned such that the second component has activating and deactivating states for placing the tag in active and deactivated states, respectively. Such conditioning includes subjecting the composite tag to predetermined magnetic fields during thermal processing stages. By switching the second component between its activating and deactivating states the tag can be switched between its active and deactived states. A reusable tag with desired step changes in flux which is capable of deactivation and reactivation is thereby realized. U.S. Pat. No. 4,980,670 describes a one bit magnetic tag formed from a magnetic material having domains with a pinned wall configuration. The resulting hysteresis characteristic for that material is such that upon subjecting the material to an applied alternating magnetic field, the magnetic flux of the material undergoes a regenerative step change in flux (Barkhausen jump) at a threshold value when the field increases to the threshold value from substantially zero and undergoes a gradual change in flux when the field decreases from the threshold value to substantially zero. For increasing values of applied field below the threshold, there is substantially no change in the magnetic flux of the material. The tag may be deactivated by preventing the domain walls from returning to their pinned condition by, for example, application of a field of sufficiently high frequency and/or amplitude. U.S. Pat. No. 4,940,966 describes the use of a plurality of magnetic elements in predetermined associations (e.g. with predetermined numbers of magnetic elements and with predetermined spacings between said elements), for identifying or locating preselected categories of articles. When the articles are caused to move relative to a predetermined interrogating magnetic field, each particular association of magnetic elements gives rise to a magnetic signature whereby the article or category of article carrying each of the predetermined associations can be recognized and/or located. U.S. Pat. No. 4,660,025 describes a marker for use in an electronic surveillance system. The marker, which can be in the form of a wire or strip of magnetic amorphous metal, is characterized by having retained stress and a magnetic hysteresis loop with a large Barkhausen discontinuity. When the marker is exposed to an external magnetic field whose field strength, in the direction opposing the instantaneous magnetic polarization of the marker, exceeds a predetermined threshold value, a regenerative reversal of the magnetic polarization of the marker occurs and results in the generation of a harmonically rich pulse that is readily detected and easily distinguished. U.S. Pat. No. 5,175,419 describes a method for interrogating an identification tag comprised of a plurality of magnetic, thin wires or thin bands which have highly rectangular hysteresis curves and different coercive forces. The wires or bands are preferably of amorphous material, but means for obtaining the highly rectangular hysteresis curves and different coercive forces are not taught; nor is the concept taught of using a time varying magnetic field superimposed on a ramp field for interrogation. U.S. Pat. No. 5,729,201 describes an inexpensive multibit magnetic tag is described which uses an array of amorphous wires in conjunction with a magnetic bias field. The tag is interrogated by the use of a ramped field or an ac field or a combination of the two. The magnetic bias is supplied either by coating each wire with a hard magnetic material which is magnetized or by using magnetized hard magnetic wires or foil strips in proximity to the amorphous wires. Each wire switches at a different value of the external interrogation field due to the differences in the magnetic bias field acting on each wire. The above identified U.S. Patents and the following related U.S. Patents assigned to the assignee of the present invention are hereby incorporated by reference: 5,528,222; 5,550.547; 5,552,778; 5,554,974; 5,538,803; 5,563,583; 5,565,847; 5,606,323; 5,521,601; 5,635,693; 5,673,037; 5,682,143; 5,680,106; 5,729,201; and 5,729,607. U.S. Patent applications assigned to the assignee of the present invention include: serial No. 08/303,965 filed Sept. 9, 1994 entitled RF Group Select Protocol, by Cesar et al.; serial No. 08/621,784, filed on March 25, 1996 entitled "Thin Radio Frequency Transponder with Lead Frame" by Brady et al. (pending); serial No. 08/626,820, Filed: 4/3/96, entitled "Method of Transporting RF Power to Energize Radio Frequency Transponders", by Heinrich et al.; application submitted 8/9/96 entitled RFID System with Broadcast Capability by Cesar et al; application submitted 07/29/96 entitled RFID transponder with Electronic Circuitry Enabling and Disabling Capability, by Heinrich et al.; serial No. 08/592,250; serial No. 08/496,838; serial No. 08/496,838; serial No. 08/909,719 ; serial No. 08/621,784,660,249; serial No. 08/660,261; serial No. 08/790,640; serial No. 08/790,639; and serial No. 08/ 681,742. The above identified U.S. Patents and U.S. Patent applications are hereby incorporated by reference. SUMMARY OF THE INVENTION An RFID tag is combined with a magnetic EAS tag. The conducting elements of the RFID tag such as the antenna or the parasitic elements used to tune the antenna characteristics may be wholly or partially made from a non-linear magnetic material which produces a large signal in a magnetic EAS detection field. The non-linear magnetic material may be coated or electroplated or electrolessly plated with a good electrical conductor to enhance the antenna characteristics of the RFID tag. The non-linear magnetic material may be advantageously connected to dielectric material used to support and/or encapsulate the antenna and electronic components of the RFID tag. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows block diagram of an RF tag of the invention; FIG. 2 shows a block diagram of an RFID tag; FIG. 3 shows an elevation sketch of a physical layout for the sketch of FIG. 2; FIG. 4 shows an alternative arrangement of FIG. 2; FIG. 5 shows perspective sketch of a preferred alternative antenna arrangement for an RFID tag; FIG. 6 shows a perspective sketch of a patch antenna mounted coplanar with a non-linear magnetic material; FIG. 7 shows an elevation sketch of the apparatus of FIG. 5; and FIG. 8 shows an elevation sketch of the apparatus of FIG. 6 showing the supporting dielectric material. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows block diagram of an RF tag 10 having tag electronics 12, a tag memory 14, and a tag power supply 16 connected to a tag antenna 18. The tag antenna 18 is shown in this embodiment made from a non-linear magnetic material 17. Such non- linear magnetic materials may have electrical conductivity insufficient for high quality antennas, and an alternative most preferred embodiment is to coat the non-linear magnetic material with a good electrical conducting material 19 such as copper, gold, or a conducting polymer. The conducting material 19 need only be as thick as the skin depth of the high frequency RF signals sent to the RFID tag 10. Such conducting material 19 may be coated on the non-linear magnetic material 17 by coating processes well known in the art such as evaporation, electroplating, or electroless plating. FIG. 2 shows a sketch of an RFID tag 10 having a tag antenna 18 electrically and spatially separated from a non- linear magnetic material 17. In the embodiment shown, the non-linear material is shown as a wire placed as a parasitic element to a dipole antenna 18 of the RFID tag 10. A preferred embodiment in this case also is to have the non-linear material 17 coated with an electrically conducting material if the electrical resistivity of the non-linear material 17 is too high. FIG. 3 shows an elevation sketch of a physical layout for the sketch of FIG. 2. The dipole antenna 18 is connected to a silicon chip 34 containing the tag memory, tag electronics, and tag power supply by wires 36 and 38. The antenna 18 and the chip 34 are mounted on a dielectric material 32. The non-linear material 17 is mounted on the opposite side of the dielectric material 32 to the antenna 18 and chip 34. In this embodiment, the non- linear material 17 may once again be coated with a good electrical conductor. FIG. 4 shows an alternative arrangement of FIG. 2. The silicon chip 34, the antenna 18, and the non- linear material 17 are all mounted on the same side of a supporting structure made of dielectric 32. In this embodiment, the non-linear material 17 may once again preferrably be coated with a good electrical conductor. FIG. 5 shows perspective sketch of a preferred alternative antenna arrangement for an RFID tag. A silicon chip 34 is electrically attached to an electrially conducting patch antenna 50. The silicon chip is also electrically attached to an electrically conducting ground plane 52, which is spatially separated from the patch antenna 50 by a dielectric material (not shown). In the embodiment shown in FIG. 5, the electrically conducting ground plane 52 is made from non-linear magnetic material 17. In this embodiment, the non-linear material 17 may once again preferrably be coated with a good electrical conductor. FIG. 6 shows a perspective sketch of a patch antenna mounted coplanar with a non- linear magnetic material 17. The magnetic material may be in the form of a wire or in the form of a sheet as shown in the diagram. FIG. 7 shows an elevation sketch of the apparatus of FIG. 5. In this case the dielectric material 32 supporting the patch antenna, the chip 34, and the ground plane 52 is explicitly shown. The alternative embodiment having a conducting material 19 coating the non-linear material is also shown. In this case, the material of the patch antenna 50 is alternatively made of a non-linear magnetic material instead of the ground plane 52. Once again, the non-linear material 17 may once again preferably be coated with a good electrical conductor. FIG. 8 shows an elevation sketch of the apparatus of FIG. 6 showing the supporting dielectric material 32.

Claims: CLAIMS What is claimed is: 1. An apparatus, comprising: a radio frequency (RF) transponder (tag), the RF tag comprising a tag antenna, tag electronics for storing information in a codable and recodable memory and for communicating information to a base station by modulating reflectance characteristics of the tag antenna, and a tag power supply; and a non-linear magnetic material operably associated with said RF tag, the non-linear magnetic material generating a varying electronic article surveillance magnetic field when the non-linear magnetic material is in a magnetic field. 2. The apparatus of claim 1, wherein said magnetic field is sinusoidally varying with a frequency fo, the electronic article surveillance magnetic field varying with a frequency having higher harmonics of fo. 3. The apparatus of claim 1, wherein the tag antenna comprises the non-linear magnetic material. 4. The apparatus of claim 3, wherein the tag antenna comprises a first wire electrically connected to a semiconductor device incorporating the tag electronics. 5. The apparatus of claim 4, wherein the first wire comprises non-linear magnetic material. 6. The apparatus of claim 5, wherein the non- linear magnetic material is coated with an electrically conducting material. 7. The apparatus of claim 4, wherein a second wire cooperates with the first wire to form the tag antenna, the second wire comprising non-linear magnetic material. 8. The apparatus of claim 6, wherein the non-linear magnetic material is coated with an electrically conducting material. 9. The apparatus of claim 4, wherein the tag antenna comprises a patch antenna electrically connected to a semiconductor device incorporating the tag electronics, the patch antenna having a ground plane. 10. The apparatus of claim 9, wherein the non-linear magnetic material is coated with an electrically conducting material. 11. The apparatus of claim 1 , wherein the tag antenna comprises a patch antenna formed by a dielectric sheet having a first side and a second side, a first electrically conducting material attached to the first side, and a second electrically conducting material attached to the second side, wherein a semiconductor device incorporating the tag electronics is electrically connected to the first electrically conducting material and the second electrically conducting material, and wherein the non-linear magnetic material is attached to the dielectric sheet. 12. The apparatus of claim 1, wherein the tag antenna comprises an electrically conducting wire antenna electrically connected to a semiconductor device incorporating the tag electronics, wherein the tag antenna and the semiconductor device are attached to a dielectric material and wherein the nonlinear magnetic material is attached to the dielectric material.

Inventors: BRADY MICHAEL JOHN, COFINO THOMAS ANTHONY, DUAN DAH-WEIH, GAMBINO RICHARD JOSEPH, MOSKOWITZ PAUL ANDREW, SCHROTT ALEJANDRO GABRIEL, VON GUTFELD ROBERT JACOB, BRADY, MICHAEL, JOHN, COFINO, THOMAS, ANTHONY, DUAN, DAH-WEIH, GAMBINO, RICHARD, JOSEPH, MOSKOWITZ, PAUL, ANDREW, SCHROTT, ALEJANDRO, GABRIEL, VON GUTFELD, ROBERT, JACOB
Applicants: BRADY MICHAEL JOHN, COFINO THOMAS ANTHONY, DUAN DAH WEIH, GAMBINO RICHARD JOSEPH, INTERMEC IP CORP, MOSKOWITZ PAUL ANDREW, SCHROTT ALEJANDRO GABRIEL, VON GUTFELD ROBERT JACOB, BRADY, MICHAEL, JOHN, COFINO, THOMAS, ANTHONY, DUAN, DAH-WEIH, GAMBINO, RICHARD, JOSEPH, INTERMEC IP CORP., MOSKOWITZ, PAUL, ANDREW, SCHROTT, ALEJANDRO, GABRIEL, VON GUTFELD, ROBERT, JACOB
Application year: 1999
Main classification: G08B13
IPC codes: G06K19, G08B13