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 radio frequency identification (RFID) systems, and more specifically to RFID transponders for use in RFID systems and the method for their assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is a continuation of application Ser. No. 09/181,505 filed Oct. 28, 1998, which is a continuation in part of U.S. application Ser. No. 09/071,413 filed May 1, 1998, now U.S. Pat. No. 5,939,984 issued Aug. 17, 1999. Said application Ser. No. 09/071,413 in turn claims the benefit of U.S. Provisional Application No. 60/070,136 filed Dec. 31, 1997. Said application Ser. No. 09/181,505 claims the benefit of U.S. Provisional Application No. 60/102,476 filed Sep. 30, 1998, and also claims the benefit of U.S. Provisional Application No. 60/093,088 filed Jul. 16, 1998. Said application Ser. Nos. 09/071,413, 60/093,088 and 60/102,476 are herein incorporated by reference in their entirety. 
     
    
     INCORPORATION BY REFERENCE  
       [0002]     The following US Patents and Patent Applications are hereby incorporated herein by reference in their entirety:  
       U.S. Patents  
       [0003]    
       
         
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Pat. No. 
                 Issue Date 
                 Filing Date 
                 Attorney Docket No. 
               
               
                   
               
             
             
               
                 5,521,601 
                 May 28, 1996 
                 Apr. 21, 1995 
                 YO995-0088 
               
               
                 5,528,222 
                 Jun. 18, 1996 
                 Sep. 09, 1994 
                 YO994-180 
               
               
                 5,538,803 
                 Jul. 23, 1996 
                 Nov. 23, 1994 
                 YO994-0073 
               
               
                 5,550,547 
                 Aug. 27, 1996 
                 Sep. 12, 1994 
                 YO994-185 
               
               
                 5,552,778 
                 Sep. 03, 1996 
                 Nov. 23, 1994 
                 YO994-0232 
               
               
                 5,554,974 
                 Sep. 10, 1996 
                 Nov. 23, 1994 
                 YO994-0071 
               
               
                 5,563,583 
                 Oct. 08, 1996 
                 Nov. 23, 1994 
                 YO994-070 
               
               
                 5,565,847 
                 Oct. 15, 1996 
                 Nov. 23, 1994 
                 YO994-0072 
               
               
                 5,606,323 
                 Feb. 25, 1997 
                 Aug. 31, 1995 
                 YO995-157 
               
               
                 5,635,693 
                 Jun. 03, 1997 
                 Feb. 02, 1995 
                 YO994-0215 
               
               
                 5,673,037 
                 Sep. 30, 1997 
                 Sep. 09, 1994 
                 YO994-184 
               
               
                 5,680,106 
                 Oct. 21, 1997 
                 Oct. 27, 1995 
                 YO995-0219 
               
               
                 5,682,143 
                 Oct. 28, 1997 
                 Sep. 09, 1994 
                 YO994-170 
               
               
                 5,729,201 
                 Mar. 17, 1998 
                 Jun. 29, 1995 
                 YO995-109 
               
               
                 5,729,697 
                 Mar. 17, 1998 
                 Apr. 24, 1995 
                 YO995-076 
               
               
                 5,736,929 
                 Apr. 07, 1998 
                 Jun. 07, 1996 
                 YO996-085 
               
               
                 5,739,754 
                 Apr. 14, 1998 
                 Jul. 29, 1996 
                 YO996-115 
               
               
                 5,767,789 
                 Jun. 16, 1998 
                 Aug. 31, 1995 
                 YO994-213 
               
               
                 5,777,561 
                 Jul. 07, 1998 
                 Sep. 30, 1996 
                 YO996-178 
               
               
                 5,786,626 
                 Jul. 28, 1998 
                 Mar. 25, 1996 
                 YO996-031 
               
               
                 5,812,065 
                 Sep. 22, 1998 
                 Dec. 08, 1995 
                 YO995-124X 
               
               
                 5,821,859 
                 Oct. 13, 1998 
               
               
                   
               
             
          
         
       
     
         [0004]    
       
         
               
             
               
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 U.S. Nonprovisional Patent Applications 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 5,729,697 
                 Mar. 17, 1998 
                 Apr. 24, 1995 
                 YO995-076 
               
               
                   
                 5,736,929 
                 Apr. 07, 1998 
                 Jun. 07, 1996 
                 YO996-085 
               
               
                   
                 5,777,561 
                 Jul. 07, 1998 
                 Sep. 30, 1996 
                 YO996-178 
               
               
                   
                   
               
             
          
         
       
     
         [0005]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 U.S. Nonprovisional Patent Applications 
               
             
          
           
               
                   
                 Application No. 
                 Filing Date 
                 Attorney Docket No. 
               
               
                   
                   
               
               
                   
                 08/681,741 
                 Jul. 29, 1996 
                 YO996-037 
               
               
                   
                 08/660,249 
                 Jun. 07, 1996 
                 YO996-084 
               
               
                   
                   
                   
                 (allowed Apr. 28, 1998) 
               
               
                   
                 08/621,784 
                 Mar. 25, 1996 
                 YO996-031 
               
               
                   
                 08/626,820 
                 Apr. 03, 1996 
                 YO995-158 
               
               
                   
                 08/646,539 
                 May 08, 1996 
                 YO996-068 
               
               
                   
                 08/681,741 
                 Jul. 29, 1996 
                 YO996-037 
               
               
                   
                 08/694,606 
                 08/09/996 
                 YO995-218 
               
               
                   
                 08/790,639 
                 Jan. 29, 1997 
                 YO997-024 
               
               
                   
                 08/790,640 
                 Jan. 29, 1997 
                 YO997-023 
               
               
                   
                 08/733,684 
                 Oct. 17, 1996 
                 YO996-195 
               
               
                   
                 08/862,149 
                 May 23, 1997 
                 YO997-116 
               
               
                   
                 08/862,912 
                 May 23, 1997 
                 YO997-115 
               
               
                   
                 08/862,913 
                 May 23, 1997 
                 YO997-114 
               
               
                   
                 08/909,719 
                 Aug. 12, 1997 
                 YO995-109B 
               
               
                   
                   
                   
                 (allowed) 
               
               
                   
                 08/935,989 
                 Oct. 23, 1997 
                 YO997-310 
               
               
                   
                   
               
             
          
         
       
     
         [0006]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 U.S. Provisional Patent Applications 
               
             
          
           
               
                   
                 Application No. 
                 Filing Date 
                 Attorney Docket No. 
               
               
                   
                   
               
               
                   
                 60/073,102 
                 Jan. 30, 1998 
                 YO897-0028P1 
               
               
                   
                 60/074,605 
                 Feb. 13, 1998 
                 YO897-0259P1 
               
               
                   
                 60/077,879 
                 Mar. 13, 1998 
                 YO997-0038P1 
               
               
                   
                 60/078,287 
                 Mar. 17, 1998 
                 YO897-0661P1 
               
               
                   
                 60/091,350 
                 Jul. 01, 1998 
                 YO897-0259P2 
               
               
                   
                 60/078,304 
                 Mar. 17, 1998 
                 YO897-0662P1 
               
               
                   
                   
               
             
          
         
       
     
         [0007]    
       
         
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
               
               
                   
                 Application No. 
                 Filing Date 
                 Attorney Docket No. 
               
               
                   
                   
               
             
             
               
                   
                 60/093,088 
                 Jul. 16, 1998 
                 38384P1 
               
               
                   
                   
               
             
          
         
       
     
         [0008]     The following further documents are also incorporated herein by reference in their entirety:  
       IBM Technical Disclosure Bulletin  
       [0009]     IBM Technical Disclosure Bulletin: Vol. 38 No. 08, August 1995, page 17, “Multifunction Credit Card Package,” by Brady, Moskowitz, and Murphy.  
       Literature Reference  
       [0010]     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, Calif., February 1997.  
       PCT Published International Applications  
       [0011]    
       
         
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
               
               
                   
                 Application No. 
                 Filing Date 
                 Attorney Docket No. 
               
               
                   
                   
               
             
             
               
                   
                 PCT/GB96/00061 
                 Jan. 15, 1996 
                 UK 9-94-066 PCT 
               
               
                   
                 PCT/EP95/03703 
                 Oct. 20, 1995 
                 YO994-242 PCT 
               
               
                   
                   
               
             
          
         
       
     
       UK Published Application  
       [0012]    
       
         
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
               
               
                   
                 Application No. 
                 Filing Date 
                 Attorney Docket No. 
               
               
                   
                   
               
             
             
               
                   
                 9710025.9 
                 May 19, 1997 
                 YO9-96-084 
               
               
                   
                   
               
             
          
         
       
     
       FIELD OF THE INVENTION  
       [0013]     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  
       [0014]     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 the RFID tags are suspect.  
         [0015]     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.  
         [0016]     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.  
         [0017]     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.  
         [0018]     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.  
         [0019]     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.  
         [0020]     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.  
         [0021]     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.  
         [0022]     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.  
         [0023]     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.  
         [0024]     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: U.S. Pat. Nos. 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: Ser. No. 08/303,965 filed Sep. 9, 1994 entitled RF Group Select Protocol, by Cesar et al.; Ser. No. 08/621,784, filed on Mar. 25, 1996 entitled “Thin Radio Frequency Transponder with Lead Frame” by Brady et al. (pending); Ser. No. 08/626,820, Filed: Apr. 3, 1996, entitled “Method of Transporting RF Power to Energize Radio Frequency Transponders”, by Heinrich et al.; application submitted Aug. 9, 1996 entitled RFID System with Broadcast Capability by Cesar et al. application submitted Jul. 29, 1996 entitled RFID transponder with Electronic Circuitry Enabling and Disabling Capability, by Heinrich et al.; Ser. Nos. 08/592,250; 08/496,838; 08/496,838; 08/909,719; 08/621,784,660,249; 08/660,261; 08/790,640; 08/790,639; and 08/681,742. The above identified U.S. Patents and U.S. Patent applications are hereby incorporated by reference.  
       SUMMARY OF THE INVENTION  
       [0025]     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  
       [0026]      FIG. 1  shows block diagram of an RF tag of the invention;  
         [0027]      FIG. 2  shows a block diagram of an RFID tag;  
         [0028]      FIG. 3  shows an elevation sketch of a physical layout for the sketch of  FIG. 2 ;  
         [0029]      FIG. 4  shows an alternative arrangement of  FIG. 2 ;  
         [0030]      FIG. 5  shows perspective sketch of a preferred alternative antenna arrangement for an RFID tag;  
         [0031]      FIG. 6  shows a perspective sketch of a patch antenna mounted coplanar with a non-linear magnetic material;  
         [0032]      FIG. 7  shows an elevation sketch of the apparatus of  FIG. 5 ; and  
         [0033]      FIG. 8  shows an elevation sketch of the apparatus of  FIG. 6  showing the supporting dielectric material. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]      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.  
         [0035]      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.  
         [0036]      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.  
         [0037]      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.  
         [0038]      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.  
         [0039]      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.  
         [0040]      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.  
         [0041]      FIG. 8  shows an elevation sketch of the apparatus of  FIG. 6  showing the supporting dielectric material  32 .