Abstract:
An RFID tag incorporating an arched buffer such that the RFID inlay containing the RFID transponder is held away from the mounting surface. This has the advantage of reducing RF signal degradation caused by the electromagnetic properties of the material.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit, under 35 U.S.C. §119 (e), of Provisional Patent Application Ser. No. 61/506,457 filed Jul. 11, 2011, the content of which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]    This invention relates to radio frequency identification (RFID) tags. 
       BACKGROUND OF THE INVENTION  
       [0003]    Radio Frequency Identification (“RFID”) is a technology for identifying or receiving information about physical objects from a distance using a small radio transponder. The components of the radio transponder, including any microprocessor or antenna, can be incorporated into an RFID inlay. An RFID inlay is typically packaged into an RFID tag to be attached to the surface of the object. Applications of this technology include retail inventory control, package and baggage tracking, authentication and security, and so forth. 
         [0004]    An RFID reader is used to communicate with an RFID tag using radio frequency (“RF”) signals to receive stored information. Often, this information is about the object to which the tag is attached. RFID readers will typically transmit a signal to the tag in order to activate the RFID tag, communicate or rewrite data, and/or to supply power to the tag. In response, the reader will receive a RF signal from the RFID tag containing information. Clear electromagnetic communications between the tag and reader are critical for proper transmission of data. Anything interfering with RF signals in the area can create a problem that must be addressed. 
         [0005]    RFID tags can suffer from significant RF signal degradation when placed in proximity to a material. The degree of degradation is related to the electromagnetic properties of the material, the distance between the antenna and the material, and the frequency of the signal. Unfortunately, many materials to which it would be desirable to attach an RFID tag have poor electromagnetic characteristics for the transmission of signals using common RFID operational frequencies. Such common materials include many metals, liquids, and even human tissues, including skin. 
         [0006]    What is desired therefore is an RFID tag that addresses these deficiencies. 
       SUMMARY OF THE INVENTION  
       [0007]    It is an object of the invention to provide an RFID tag designed to minimize RF signal degradation due to proximity to a mounting surface. The RFID tag is formed such that the RFID inlay portion of the tag is held away from the surface to which the tag is affixed. This arrangement has the advantage of creating a gap between the RFID transponder antenna and the mounting surface such that the degree of degradation caused to the signal from the proximity of the surface is reduced. 
         [0008]    Alternative embodiments of the invention affix the RFID tag to the mounting surface in such a way as to describe a flexible arch, the RFID inlay portion being disposed in the central portion of the arch, such that it is held away from the mounting surface. The arched shape of the central portion has the advantage of inherently resisting pressure that would push the RFID inlay portion toward the mounting surface. This helps to avoid unwanted RF signal degradation from proximity to the mounting surface. 
         [0009]    Other alternative embodiments incorporate perforations such that the central portion of the RFID tag containing the RFID inlay can be cleanly and easily removed from the tag while it is mounted. 
         [0010]    Still other alternative embodiments of the invention can incorporate tamper-evident materials such that attempts to remove the RFID tag are easily detectible upon visual inspection. 
         [0011]    In further embodiments, portions of the RFID tag can be extended in such a way that the RFID tag may adhere to itself in some locations, such that the RFID tag forms a wrist band. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0012]      FIG. 1  is a perspective view of an RFID tag affixed to a mounting surface; 
           [0013]      FIG. 2  is an underside view of the RFID tag of  FIG. 1 ; 
           [0014]      FIG. 3  is a side view of the RFID tag of  FIG. 1 ; 
           [0015]      FIG. 4  is a perspective view of an RFID tag according to an alternate embodiment of the invention; 
           [0016]      FIG. 5  is a side view of the RFID tag of  FIG. 4 ; 
           [0017]      FIG. 6  is an underside view of the RFID tag of  FIG. 4 ; 
           [0018]      FIG. 7  is a side view of the RFID tag of  FIG. 4 ; and 
           [0019]      FIG. 8  is side cross-sectional view of an RFID tag according to an alternate embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]      FIG. 1  illustrates an overview of a RFID tag  1  affixed to a mounting surface  2 , according to an embodiment of the invention. RFID tag  1  comprises an RFID inlay  3 , and mounting strip  4 . RFID inlay  3  may comprise a radio transponder, antenna, power source, microprocessor, and/or storage space, which together are adapted to receive a radio frequency signal from an RFID reader (not shown) and respond with a radio frequency signal containing information. RFID inlay  3  may be attached, laminated, incorporated into, or otherwise conformed to mounting strip  4  in a suitable manner. Mounting strip  4  may comprise a plastic, paper, composite, laminar, or other suitable material for affixing objects. In alternative embodiments, mounting strip  4  may comprise, in whole or in part, a tamper-evident material (not shown). Mounting strip  4  comprises central portion  5 , first side portion  6 , and second side portion  7 . First side portion  6  has a first inner end  8  disposed toward the central portion  5  and a first outer end  9  coincident with a first edge  10  of the mounting strip  4 . Second side portion  7  likewise has a second inner end  11  disposed toward the central portion  5  and a second outer end  12  coincident with a second edge  13  of the mounting strip  4 . First side portion  6  and second side portion  7  each have an adhesive surface (not shown) which when in contact with mounting surface  2 , serve to affix RFID tag  1 . 
         [0021]      FIG. 2  illustrates an underside view of the RFID tag  1 , showing portions disposed in the direction of a mounting surface (not shown). First side portion  6  comprises first adhesive surface  14 , and second side portion  7  comprises second adhesive surface  15 . The adhesive surfaces may comprise a gum, glue, hook-and-loop, or other suitable surface for affixing the RFID tag to a mounting surface (not shown). In alternative embodiments, first inner end  8  and second inner end  11  are perforated, such that central portion  5  can be easily and cleanly removed from the RFID tag  1  while adhesive surfaces  14  and  15  are affixed to a mounting surface (not shown). 
         [0022]      FIG. 3  illustrates a side view of the RFID tag  1 , which is shown in its intended configuration when affixed to a mounting surface (not shown). Adhesive surfaces  14  and  15  are affixed to the mounting surface (not shown) in such a way that a length  16  of central portion  5  is greater than a distance  17  between first inner end  8  and second inner end  11 , causing central portion  5  to flexibly describe an arch, and lifting central portion  5  away from the mounting surface (not shown) by a maximum distance  18 . 
         [0023]      FIG. 4  illustrates an overview of an RFID tag  19  according to an alternate embodiment of the invention. RFID tag  19  may comprise all of the features and materials of RFID tag  1  (not shown) as shown and described above with regard to  FIG. 1 , including mounting strip  20 , RFID inlay  21 , first side portion  22 , second side portion  23 , and central portion  24 . Each of these portions is arranged with respect to the others as shown and described with respect to  FIGS. 1-3 . In addition, RFID tag  19  may comprise extended portion  25  that extends in a continual manner from second side portion  23  such that the overall length of RFID tag  19  is increased in the direction of second side portion  23 . 
         [0024]      FIG. 5  illustrates a side view of RFID tag  19  according to an alternate embodiment of the invention. Relationships between the components of RFID tag  19  may be as shown and described with respect to  FIG. 3  above, including adhesive surfaces  26  and  27 . In addition, RFID tag  19  may comprise extended portion  25  as shown and described with respect to  FIG. 4 . Adhesion locations  28  and  29  are disposed on extended portion  25  to provide a corresponding surface upon which adhesive surfaces  27  and  26  may adhere, respectively. Adhesion locations  28  and  29  may comprise the material of extended portion  25 , or may be treated or comprised in such a way as to promote adhesion, or to render tampering evident. 
         [0025]      FIG. 6  illustrates an underside view of RFID tag  19  according to an alternative embodiment of the invention. RFID tag  19  may comprise all of the features of RFID tag  1  as shown and described with respect to  FIGS. 4 and 5 , including mounting strip  20 , RFID inlay  21 , first side portion  22 , second side portion  23 , central portion  24 , adhesive surfaces  26  and  27 , and adhesion locations  28  and  29 . Each of these portions is arranged with respect to the others as shown and described with respect to  FIGS. 1-3 . In addition, RFID tag  19  may comprise extended portion  25  that extends in a continual manner from second side portion  23  such that the overall length of RFID tag  19  is increased in the direction of second side portion  23 . 
         [0026]      FIG. 7  illustrates a side view of RFID tag  19  which is similar to the side view shown and described with respect to  FIG. 5  except in that RFID tag  19  is shown in an assembled state where corresponding adhesion surface and location  26  and  29 , as well as corresponding adhesion surface and location  27  and  28  are joined to form fixations  30  and  31 , respectively. Fixations  30  and  31  are formed in such a way that RFID tag  19  may have been fixedly looped through or around an object, e.g., around a wrist to form a wrist band. Fixations  30  and  31  are further formed and located to cause central portion  24  to flexibly describe an arch, and to lift central portion  24  away from the object about which RFID tag  19  is fixedly looped by at least distance  32 . 
         [0027]      FIG. 8  illustrates an overview of an RFID tag  1 ′ according to an alternate embodiment of the invention. RFID tag  1 ′ may comprise all of the features and materials of RFID tag  1  (not shown) as shown and described above with regard to  FIG. 1 , including mounting strip  4 , central portion  5 , first side portion  6 , and second side portion  7 . The main difference between the embodiment shown in  FIG. 1  and the embodiment shown in  FIG. 8 , however, is that the RFID tag  1 ′ shown in  FIG. 8  further includes a substrate  33 , on which the first side portion  6  and the second side portion  7  of mounting strip  4  are affixed, such as by an adhesive, heat sealing, ultrasonic welding, or the like, with the air gap created between the central portion  5  and the substrate  33 . The rear surface of substrate  33  may then be provided with an adhesive, such as a gum, glue, hook-and-loop, or other suitable surface for affixing the RFID tag  1 ′ to a mounting surface (not shown). By providing the mounting strip already affixed to the substrate  33 , with the air gap created therebetween in the vicinity of the central portion  5 , attachment to the mounting surface (not shown) may be facilitated, in that it is not necessary to ensure that the first side portion  6  and the second side portion  7  are properly positioned on the mounting surface in order to create the air gap. Also, it should be noted that the mounting surface may comprise a surface of any of numerous articles, such as a box, a container, a wrist band, or substantially any other surface where provision of an RFID tag may be desirable.