Abstract:
A method for using multi-functional RFID tag assemblies, passive repeater systems and modular antenna systems. One embodiment comprises a method for communicating with an RFID tag by providing a passive loop modular antenna system, moving the RFID tag through a field related to the modular antenna system; and transmitting energy through the antenna to communicate with the RFID tag. The invention also comprises a method of configuring an RFID passive loop modular antenna system. The invention also comprises a method for communicating with an RFID tag by providing a passive loop in proximity with the RFID tag. RFID tags are also integrated into a carton by affixing an RFID label or embedding an RFID tag. Such cartons can be used to track items throughout the manufacturing, transporting, storing, distributing and delivering processes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This invention is a continuation-in-part of U.S. Ser. Nos. ______ (Atty Docket No. EMS-02-015U), filed Aug. 8, 2001, which claims benefit under 35 U.S.C. 119 (e) of U.S. Provisional Application No. 60/239,475, filed Oct. 10, 2000; ______ (Atty Docket No. EMS-02-016U), filed Aug. 8, 2001, which claims benefit under 35 U.S.C. 119 (e) of U.S. Provisional Application No. 60/224.932, filed Aug. 11, 2000; and ______ (Atty Docket No. EMS-02-017U), filed Aug. 8, 2001, which claims benefit under 35 U.S.C. 119 (e) of U.S. Provisional Application No. 60/224,855, filed Aug. 11, 2000, each of which is incorporated in its entirety by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates in general to radio frequency identification (RFID) devices. More particularly, the invention relates to the use of multi-functional RFID tag assemblies, passive repeater systems and modular antenna systems to track containers and/or products.  
         BACKGROUND OF THE INVENTION  
         [0003]    RFID systems are well known in the art. Such systems include relatively large packages containing battery powered transmission/receiving circuitry, such as the identification system disclosed in U.S. Pat. No. 4,274,083, to passive systems in which the transponder receives its power from the base station or interrogator, such as the identification system disclosed in U.S. Pat. No. 4,654, 658.  
           [0004]    A typical RFID system is made up of reusable tags, an antenna system that interrogates the tags via an RF link and a controller. The host (or computer) system interfaces with the controller and directs the interrogation of the tags. The RFID system thus provides effective means of identifying, monitoring, and controlling materials in a closed loop process. In a factory environment, the tags are employed as the transport mechanism between “islands of automation,” providing a record of each process which can be acted upon immediately or downloaded later for analysis. In operation, as a tag passes near an RFID antenna unit, an antenna emits RF signals towards the tag and the tag transmits responses to the antenna. The tags can be powered by an internal battery (i.e., an “active” tag) or by inductive coupling receiving induced power from the RF signals emitted from the antenna (i.e., a “passive” tag). Passive tags have zero maintenance and virtually unlimited life. The life span of an active tag is, however, limited by the lifetime of the battery, although some tags offer replaceable batteries. RFID tags also have limited applicability due to limitations on the operating range.  
           [0005]    RFID antenna units are typically employed in manufacturing environments and are used to read tagged items as they pass certain points. The antennas are generally operated in the ranges of 2.45 GHz, 900 MHz or 125 KHz. The noted frequencies are employed to achieve a longer antenna field range. It is, however, well known that at 2.45 GHz and 900 MHz the fields produced by the antenna(s) are affected by virtually everything that passes through the field, including metals and moisture. Metal causes extreme reflection of the fields, while moisture causes extreme absorption of the field. Therefore, any metal object or anything containing moisture, such as the human body, will cause extreme disruption of the field and, hence, the communication of the antenna with the tags.  
           [0006]    In an effort to eliminate or substantially reduce the extreme reflection cause by metal objects passing through the field, multiple reflective shields have been employed. The shields cause the field to continuously reflect until it eventually contacts a tag. This is, however, a costly and often impractical solution.  
           [0007]    At the other extreme (i.e., 125 KHz), better environmental performance is achieved because metal and moisture generally have less affect on the field. There are, however, several significant drawbacks associated with the noted operating frequency. A major drawback is the high cost, since 100 or more turns in the antenna coil are required to achieve the 125 KHz operating range. Alternatively, an operating frequency of 13.56 MHz can be employed. Although the noted frequency achieves good environmental performance, it is often unable to achieve the operating range of the aforementioned frequencies.  
           [0008]    It is therefore an object of the present invention to utilize an RFID antenna system that comprises modular antenna segments that can be connected in a variety of configurations for multiple applications.  
           [0009]    It is therefore an object of the present invention to utilize an RFID tag assembly and system to track a product or other article during transportation, storage and distribution.  
           [0010]    It is another object of the invention to utilize an RFID tag assembly and system to extend the operating range of a conventional RFID tag.  
           [0011]    It is yet another object of the invention to utilize an RFID tag assembly and system to reduce the orientation sensitivity of a conventional RFID tag.  
           [0012]    It is still a further object of the invention to utilize cartons having integrated RFID tags to track and identify items during transportation, storage and distribution.  
         SUMMARY OF THE INVENTION  
         [0013]    In accordance with the above objects and those that will be mentioned and will become apparent below, the invention comprises a method for communicating with an RFID tag by providing a passive loop modular antenna system, moving the RFID tag through a field related to the modular antenna system; and transmitting energy through the antenna to communicate with the RFID tag. Preferably, the antenna system comprises a plurality of interchangeable segments with a controller in communication with the segments. The invention also comprises a method of configuring an RFID passive loop modular antenna system, comprising the steps of designing at least a first antenna system configuration, validating the design of the first antenna system configuration, and providing at least one assembly drawing comprising a plurality of antenna segments and the control parameters for the first antenna system configuration. This method may also comprise the steps of controlling the operation of said first antenna system configuration after assembly, testing the assembled first antenna system configuration and/or providing a memory for storing a plurality of different antenna segments, a plurality of antenna system configurations, and control parameters for the plurality of antenna system configurations.  
           [0014]    The invention also comprises a method for communicating with an RFID tag, comprising providing an RFID tag attachable to a first item, providing a first passive loop in proximity with the RFID tag, and communicating with the RFID tag by relaying signals through the passive loop. Optionally, the RFID tag can be detached from the first passive loop and attaching it to a second item. Preferably, the step of communicating with the RFID tag comprises magnetically inducing a current in the first passive loop. The use of the passive loop can extend the range of the RFID tag. Placing the RFID tag and the passive loop in substantially different planes can reduce the directional sensitivity of the RFID tag. In one embodiment of the invention, the first passive loop is placed in proximity with a plurality of RFID tags, such as a ULD having a plurality of items with RFID tags. A second passive loop can be placed in proximity to the first passive loop to provide an additional relay for RF signals.  
           [0015]    The invention also comprises integrating an RFID tag into a carton by affixing an RFID label or embedding an RFID tag. Preferably, the RFID tag assumes a three dimensional configuration when the carton is expanded. Such cartons can be used by supplying the carton to a user, placing an item into the carton, receiving the carton from the user, and communicating with the RFID tag to track the carton. A passive loop can be used to relay signals with the RFID tags. Preferably, a plurality of cartons each with integrated RFID tags are aggregated. A supplemental RFID tag may be secured to the aggregated plurality of cartons to track the aggregated plurality of cartons. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    Further features and advantages will become apparent from the following and more particular description of the preferred embodiments of the invention, as illustrated in the accompanying drawings, and in which like referenced characters generally refer to the same parts or elements throughout the views, and in which:  
         [0017]    [0017]FIG. 1 is a schematic illustration of one embodiment of the modular RFID antenna system according to the invention;  
         [0018]    FIGS.  2 - 4  are schematic illustrations of additional embodiments of RFID antenna systems according to the invention;  
         [0019]    [0019]FIG. 5 is a schematic illustration of the configuration system modules according to the invention;  
         [0020]    [0020]FIG. 6 is a perspective view of one embodiment of the RFID tag system according to the invention;  
         [0021]    [0021]FIG. 7 is a perspective view of an article having a removable RFID tag thereon according to the invention;  
         [0022]    [0022]FIG. 8 is a perspective view of a further embodiment of the RFID tag assembly according to the invention.  
         [0023]    [0023]FIG. 9 is a plan view of one embodiment of the passive repeater apparatus accordingly to the invention;  
         [0024]    [0024]FIG. 10 is a perspective view of an additional embodiment of the passive repeater system according to the invention;  
         [0025]    [0025]FIG. 11 is a perspective view of a further embodiment of the passive repeater system, illustrating a passive repeater “container” system according to the invention;  
         [0026]    [0026]FIG. 12 is a perspective view of yet a further embodiment of the passive repeater system, illustrating a passive repeater “shipping container” system according to the invention;  
         [0027]    [0027]FIGS. 13 and 14 are schematic views of an applicator for integrating RFID labels with containers according to the invention;  
         [0028]    [0028]FIG. 15 is a schematic view of a method of the invention comprising communicating with an RFID label using a three dimensional antenna.  
         [0029]    [0029]FIG. 16 is a schematic view of an RFID antenna system of the invention retrofitted to a trailer;  
         [0030]    [0030]FIG. 17 is a schematic view of an RFID antenna system of the invention retrofitted to a cargo truck; and  
         [0031]    [0031]FIG. 18 is a schematic view of an RFID antenna system of the invention placed at then access to a loading dock.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    In this invention, modular radio frequency identification device (RFID) antenna and tag systems are used to identify and track items throughout manufacture, warehouse storage, transportation, distribution and retail sale.  
         [0033]    In a first embodiment, the invention is directed to the use of a modular RFID antenna system comprising a plurality of easy-to-assemble modular RFID antenna segments that can be connected in multiple configurations to allow omni-directional communication with at least one transponder or tag located on one or more items that pass through the field of the antenna system. The invention also includes the method of using a system, such as a computer system to design, order, configure, test and operate the modular RFID antenna systems for a given application.  
         [0034]    Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.  
         [0035]    Referring first to FIG. 1, there is shown one embodiment of an assembled RFID antenna system  10 , according to the invention. As illustrated in FIG. 1, tags  11  located on multiple items or containers  12  pass through the field of antenna system  14 . The system  14  comprises a plurality of modular antenna segments or panels  16 ,  18 ,  20  and  22  that are connected in a desired configuration to allow omni-directional communication with tags  11 .  
         [0036]    Next, referring to FIG. 2, an antenna system  24  configuration adapted to ground or floor “pass-thru” applications is shown adapted for moving tags through in the direction of Arrow A. The system preferably includes a plurality of low-profile panels  23  disposed proximate the floor or ground of the structure (or building). The panels  23  are preferably in communication with each other via cable system  26 . However, in this and other referenced embodiments herein, the panels  23  can be employed separately. A controller  28  controls the operation of the panels  40 . Also preferably, each panel  23  comprises modular elements  30  and  32  that can be chosen to create a panel having the desired characteristics.  
         [0037]    [0037]FIG. 3 shows a conveyor “pass-thru” or “gate” antenna system  34 . The system  34  facilitates effective RF communication by and between the inter-connected antenna panels  23  and one or more tags that pass through the antenna field (via conveyor  36 ) in the direction denoted by Arrow B.  
         [0038]    Referring to FIG. 4, antenna system  38  can be readily adapted to facilitate multiple paths (i.e., direction, width, etc.) through the antenna field(s), such as the path denoted by Arrow C. The system  38  can further be adapted to provide highly effective, omni-directional RF communication by and between the panels  23  and one or more tags within the antenna field(s). System  38  includes a plurality of low-profile panels  23  that are disposed in an upright position. The panels  23  are secured in the upright position and desired locations via supports  40 . Alternatively, the panels may be stacked to provide additional flexibility in adapting the system  38  to facilitate multiple paths through the antenna fields.  
         [0039]    To increase the read/write operating range of a RFID modular antenna system or configuration, the present invention includes the use of novel antenna-switching circuitry that allows adequate tag coverage at an increased range, while maintaining the radiation limits within those imposed by the FCC/CE. According to the invention, the driven antenna panels (e.g.,  23 ) are switched on and off in an inverted manner at a rate that accommodates complete RF communication between the antenna panels and tags, while at the same time allowing for averaging or quasi-peak detection as allowed by the FCC/CE.  
         [0040]    To achieve successful communication between a respective antenna panel and the tags, the transmitting antenna panel preferably continuously powers the passive tags. Once the tag is powered, a transmitter modulates the very field that powers the tag. The tag then communicates with the receiver via a separate receiving antenna while remaining powered by the transmit antenna.  
         [0041]    A key element of the present invention is the design and configuration of such systems using, for example, a computer having a PC—Windows® or Macintosh® based interface for design and configuration of a desired modular RFID antenna system. Referring to FIG. 5, a software component  42  preferably includes the following sub- systems or modules: memory  44 , design  46 , design validation  48 , bill of materials  50 , and configuration  52 . Each sub-system is discussed in detail below.  
         [0042]    Memory: Each sub-system is preferably in communication with the memory module or sub-system  44 . According to the invention, the memory sub-system  44 , includes at least the following databases or information: a plurality of available modular antenna systems, mechanical elements or parts for each antenna system, and set-up and operation parameters.  
         [0043]    Design: According to the invention, the design sub-system  46  allows the user to select one or more of a plurality of available modular antenna systems. Such systems include the systems discussed above. After the desired system is selected, the design sub-system  46  then provides the user with a design menu that includes a parts list prompt that links the user to a parts list menu that provides list of mechanical elements or parts that are comparable with the selected system. Preferably, as discussed below, the design sub-system  46  further includes generating drawings.  
         [0044]    Design Validation: According to the invention, the design validation sub-system  48  includes validating the selected antenna system and mechanical elements. In a preferred embodiment of the invention, if one or more of the selected mechanical elements are incorrect and/or incomparable with the selected antenna system, the design validation sub-system  48  will provide an error message and details relating thereto. The design validation sub-system  48  will further restrict the user from printing a bill of materials.  
         [0045]    Bill of Materials: According to the invention, the bill of materials sub-system  50  generates a bill of materials. The bill of materials is preferably in tabular form and, as discussed in detail below, includes at least the following fields: line item fields, including supplier part number, part description, quantity, unit price and extended price; and global item fields, including customer name, address and other identifier information and (e.g., customer number), project name, P.O. number, shipping information and special instructions. The noted information is preferably provided in a printable format that can, if desired, be attached as an addendum to a purchase order.  
         [0046]    In an additional envisioned embodiment of the invention, the bill of materials sub-system  50  also provides a bill of materials that is exportable via electronic media in formats that are compatible with the user&#39;s (or customer&#39;s) and supplier&#39;s (or vendor&#39;s) purchasing/receiving systems. As will be appreciated by one having ordinary skill in the art, the noted feature would facilitate E-commerce data/information transmission.  
         [0047]    Configuration: An important sub-system of the software component is the configuration sub-system  52 . According to the invention, the configuration sub-system  52  assembles, configures and controls the antenna system. Thus, the configuration sub-system  52  includes at least three (3) components: assembly, set-up and test. Preferably, these noted components are accessible via a configuration menu. According to the invention, the assembly component generates installation assembly drawings. The drawings can be selected automatically or manually from a set of predefined drawings (stored in memory module  44 ). The drawings are preferably provided in a format that is displayable and printable by the user. The files may also be exportable in Auto CAD formats. The set-up component provides the user with the necessary RF communication parameters. The set-up component thus includes at least the following: a plurality of baud rates, interface options (e.g., hardware protocols), operation mode (e.g., test or run) and read parameters (e.g., continuous, non-continuous, start address, etc.). The test component tests the assembled antenna system. The test component preferably provides a plurality of commands to verify the presence and operation health of a respective one and/or a plurality of the antenna panels.  
         [0048]    The methods of the invention also include using RFID tags having passive loops, preferably in conjunction with antenna systems such as the ones disclosed above. Referring now to FIG. 6, there is shown a first embodiment of the RFID tag assembly  60  useful in the practice of the invention. Tag assembly  60  includes a substrate  62 , a conventional RFID tag  64  and at least one conductive member (i.e., antenna), such as a passive loop or dipole  66 , adapted to transmit and receive RFID signals. As discussed in detail below, the tag  64  and passive loop  66  are preferably disposed on at least one surface or portion of the substrate  62 . In a preferred embodiment, the tag  64  is disposed in the interior region defined by the loop  66  (hereinafter referred to as the “loop region”) or otherwise proximate to loop  66 .  
         [0049]    To facilitate attachment of the substrate  62  to a shipping container  68  or other article, the substrate  62  preferably includes conventional adhesive means (e.g., two sided tape) disposed on at least one surface or portion of the substrate  62 , more preferably, on a surface opposite of the tag  64  and passive loop  66 . According to the invention, the substrate  62  can also be secured or directly bonded to a container or other article via conventional adhesives (e.g.,epoxy) or conventional mechanical means.  
         [0050]    The substrates useful in the practice of the invention include various non-conductive materials, such as paper, synthetic paper, cardboard, polyamide, polyester, Teflon™, ABS™, and like materials, or a material having a non-conductive area comprising the noted materials. In a preferred embodiment of the invention, the substrate comprises paper.  
         [0051]    According to the invention, the passive loop  66  is in communication with (i.e., coupled to) the tag  64 . As will be appreciated by one having ordinary skill in the art, the loop  66  can be coupled to the tag  64  by various conventional means. In a preferred embodiment of the invention, the loop  66  is magnetically coupled to the tag  64 . The passive loop  66  can comprise various sizes and configurations, such as the substantially square shaped loop shown in FIGS. 6 and 7. The loop  66  can also be substantially larger than the tag  64  and, hence, is merely limited by the size of the substrate  62 .  
         [0052]    The passive loop  66  can also be constructed from various conductive materials that can be applied to or embedded in the substrate  62  by conventional means. For example, the passive loop  66  can comprise a carbon/graphite bearing conductive ink that is printed or silk-screened on the substrate  62 , comprise a metalized paint directly applied to the substrate  30 , a substantially metalized or metallic foil (or wire) bonded to the substrate  62  or a foil or wire embedded in the substrate  62 . In a preferred embodiment of the invention, the passive loop  66  comprises a copper foil that is bonded to the substrate  62  by conventional means.  
         [0053]    As will be appreciated by one having ordinary skill in the art, virtually all conventional RFID tags (e.g., 2.45GHz, 125KHz, 13.5 MHz, 900 MHz) can be employed within the scope of the present invention. Such tags are described in numerous prior art references, including U.S. Pat. Nos. 6,121,878; 6,118,379; and 6,100,804, which are incorporated by reference herein.  
         [0054]    According to the invention, the passive loop  66  has an inductance and a capacitance that is tuned to or close to the operating frequency of the respective tag  64 . In additional envisioned embodiments of the invention, the passive loop  66  has a distributed capacitance, or a combination of fixed and distributed capacitance that is tuned to or close to the operating frequency of the tag  64 .  
         [0055]    Preferably, the use of the tag system  60  of the invention includes removing tag  64  from substrate  62  and securing to an article, such as a product  68  or product container  70 . Thus, information and data acquired during packaging, inventory or transport remains with the article through subsequence processes or use. As will be appreciated by one having ordinary skill in the art, the article can be a product or item contained in a larger shipping container, a product container transported in a larger container (e.g., shipping container), or a product container transported on a pallet. Thus, tag  64  is preferably detachable from the substrate  62 . As will be appreciated by one having ordinary skill in the art, various methods may be employed to facilitate the detachment of the tag  64  from the substrate  62 . In one embodiment of the invention, the substrate  62  includes a substantially continuous line of perforations  69  disposed proximate the tag  64 . Accordingly, the separable substrate section or tag assembly preferably includes conventional adhesive means on the rear portion thereof for subsequent attachment of the tag  64  to a product  68 , container  70  or other desired article (discussed in detailed below). However, as will be appreciated by one having ordinary skill in the art, the tag assembly  60  can also be attached to a product or other article by mechanical means.  
         [0056]    In use, tag system  60  is initially attached to shipping container  70 . When the product  68 , such as the computer illustrated in FIG. 7, is removed from the shipping container  70 , the tag  64  is removed from the substrate  62  and placed on the product  68 . Thus, any data or information acquired while the product  68  is in the shipping container  70  remains with the product  68  throughout its lifetime.  
         [0057]    Referring now to FIG. 8, additional embodiments of RFID tag systems may be used with the invention. In addition to increasing the operating range of the tags  64  associated therewith, the noted embodiments substantially reduce the orientation sensitivity that is commonly associated with the tags  64 . For example, tag system  72  comprises a substantially planar substrate  74  having at least one tag  64  with associated first passive loop  76  and at least a second passive loop  78  disposed thereon. The first and second passive loops  76  and  78  are preferably disposed on opposing ends of the substrate  74  and are preferably in communication with each other. Also preferably, substrate  74  preferably includes a fold line  80  that facilitates folding of the substrate  74  into a substantially “L” shaped configuration so that it may be attached to an edge of shipping container  70  to facilitate optimal transmission and receipt of RF signals in at least two planes. Two or more tag systems  72  can also be employed within the scope of the invention (i.e., disposed on different edges of the container  70 ) to further reduce the orientation sensitivity of the tags  64  and, hence, RFID system. Similarly, tag system  82  may comprise tag  64  with first passive loop  84  and two additional passive loops  86  and  88  disposed on a “multi-panel” substrate  90 . The “multi-panel” substrate  90  is flexible enough to be bent allowing it to be attached to a corner of product container  70  to facilitate optimal transmission and receipt of RF signals in at least three planes.  
         [0058]    The methods of the invention further include the use of a RFID passive repeater system comprising one or more passive loops (i.e., antenna means) preferably disposed on a larger member that significantly enhances the operating range of individual tags positioned proximate a respective passive loop. As will be appreciated by one having ordinary skill in the art, the invention is particularly useful in applications where multiple items are grouped together into a larger package, shipping unit, load, or other grouping of tagged items and need to be read at a distance greater than that which would be allowed by the relatively smaller size of the individually tagged items. Examples would be a pallet of boxes or items, a cart or bin or tote used to contain multiple items, a large box or packaging containing multiple small items, a shipping container with multiple tagged items, or as a method of extending the read/write range between an RFID reader/writer and a designated tag.  
         [0059]    The implementation of the passive repeater systems may be one large loop (with suitable resonating capacitance) coupled directly to an RFID tag  64 , or as two or three resonant loops coupled magnetically to another loop in order to collect the energy from two or more resonant loops and convey it back to the RFID tag  64 . As discussed above, the coupling mechanism for this collection loop into the RFID chip  64  may be by direct connection, or through magnetic coupling into another resonant loop directly attached to RFID tag.  
         [0060]    As shown in FIG. 9, passive repeater system  92  includes a substrate  94  having first and second surfaces, a conventional RFID tag  64  and at least one passive conductive member or loop  96  adapted to transmit and receive RFID signals. Alternatively, as shown in FIG. 6, loop  96  may be used with tag system  60 , or other suitable RFID tag systems.  
         [0061]    According to the invention, the loop  96  is in communication with (i.e., coupled to) the tag  64 . Tag  64  is preferably disposed on a surface of the substrate  94  proximate the loop  96  and is in communication therewith. According to these embodiments of the invention, the maximum distance from the tag  64  to a point on the loop  96  (designated by Arrow D) is approximately 20 ft, more preferably, the maximum distance is approximately 15 ft. In a preferred embodiment of the invention, the maximum distance (D) from the tag  64  to the loop  96  is in the range of approximately 8-12 ft.  
         [0062]    According to the invention, the passive loop  96  can comprise various configurations and conductive materials that can be produced, applied to or embedded in the substrate  94  in various manners. For example, the loop  96  can be silk-screened on the substrate  94 , comprise a metalized paint directly applied to the substrate  94 , a substantially metalized or metallic foil bonded to the substrate  94  or a foil embedded in the substrate  94 . In a preferred embodiment of the invention, the loop  96  comprises a copper foil that is bonded to a surface of the substrate  94  by conventional means. In additional envisioned embodiments of the invention, two or more passive loops are employed, preferably bonded to one surface or side of a substrate with an insulating layer disposed therebetween.  
         [0063]    According to the invention, the passive loop  96  preferably have an inductance and a capacitance that is tuned to or close to the operating frequency of the respective tag(s)  64  (e.g., common ISM bands). In additional envisioned embodiments of the invention, the loop  96  has distributed capacitance, or a combination of fixed and distributed capacitance that is tuned to or close to the operating frequency of the respective tag(s)  64 .  
         [0064]    Applicant has found that effective enhancement of RFID signals can be achieved with a passive repeater system having a loop region area in the range of approximately 1.0 sq. in. to 400 sq. ft.  
         [0065]    As illustrated in Figs.  10  and  11 , passive repeater system  98  is preferably disposed proximate a single tag  64 , a group of tags, or placed within an aggregate grouping of items containing tags  64  or placed on or built into a unit load device (ULD) used to group, contain, hold, transport, or otherwise group for storage, transport, or delivery a group of items that are tagged, such as shipping pallet  100  or container  102 . According to the invention, the passive repeater system  98  is preferably magnetically coupled to the tag(s)  64 . Passive repeater system  98  may be substantially planar, or may be configured to define two or three planes to optimize RF performance.  
         [0066]    [0066]FIG. 10 shows passive repeater system  98  used with palletized group of boxes  104 . In the noted embodiments, the passive repeater system  98  is disposed on top of the boxes and/or within the group of boxes. Alternatively, passive repeater system  98  may be embedded in the pallet  100 . FIG. 11 shows passive repeater system  98  used with container  102  having at least one box  104 . The passive loop  106  of passive repeater system  98  may be disposed on or embedded in one surface of container  102 . In an additional embodiment of the invention, discussed below, the passive repeater system  98  further comprises an RFID tag  108  preferably disposed on an outer surface of the container  102  proximate the passive loop  106  to allow separate identification and tracking of the container  102  separate from the group of boxes  104 .  
         [0067]    [0067]FIG. 12 shows a passive repeater system  98  comprising at least one substantially elongated panel  110  having at least one passive loop  112  thereon that is positioned in a shipping container  102  with packages  104 . According to the invention, the panel  110  is preferably constructed of plastic, cardboard, wood and other like materials, and can comprise various shapes and sizes. In these embodiments, passive repeater system  98  would have a loop region area in the range of approximately 1.0 sq. in. to 400 sq. ft. In a preferred embodiment of the invention, the loop region area is in the range of approximately .25 sq. ft to 100 sq. ft.  
         [0068]    In further envisioned embodiments of the invention, an additional passive loop, such as passive loop  114  shown in phantom in FIG. 12, is employed with coils magnetically or electrically coupled to at least one internally disposed panel  110 . According to the invention, the RF field at or around the frequency of operation of the RFID system is translated from the area outside of the shipping container  102  where the RFID equipment is located to the inside of the container  102  where the panel  110  is positioned to further enhance communication with the tags  64  on boxes  104  inside the shipping container  102 . Also, a separate tag  116  may be disposed proximate to passive loop  114  to acquire and store information about the container  102  and/or it&#39;s contents. Information such as the container contents, serial number, origin and destination points, transport identification (e.g., flight number), tracking number for the entire shipment and/or any data related to the container  102  can thus be readily accessed at one convenient point.  
         [0069]    Yet another embodiment of the invention is directed to the use of cartons having integrated RFID tags and the related methods of integrating RFID tags with such cartons. For example, FIG. 13 shows the process of adding an RFID tag comprising a label  116  that is affixed by applicator  118  to collapsed cartons  120 . Preferably, the label  116  is attached so that when the carton  120  expanded by folding upright, the label adopts a three dimensional shape that optimizes its RF performance. Alternatively, as shown in FIG. 14, RFID tag  122  is embedded into carton  120  by applicator  124 . Again, preferably when carton  120  is folded into its useful shape, tag  122  assumes a three dimensional conformation.  
         [0070]    Alternatively, labels  116  or tags  122  can be affixed or embedded into cartons  120  that assume a one dimensional conformation. In such embodiments, it is preferably to utilize antenna systems having a three dimensional field, such as system  126  used with conveyor  128  in FIG. 15.  
         [0071]    The methods of using the disclosed antenna and RFID tag systems offers superior identification and tracking of goods through all aspects of manufacture, storage, transportation, distribution and sale. One example of the method, without limiting the applicability of the invention, is a delivery company tracking packages for shipment. The delivery company can provide customers with cartons  120  having affixed or embedded labels  116  or  122 . The customer then expands the boxes and uses them to package goods for delivery. Optionally, the customer can take advantage of the RFID tags on the cartons to track and identify the goods in-house. The delivery company picks up the carton  120 , and by using pass-through antennas or other suitable antennas, can read and write information to the carton at the time of pick up. The carton can then be tracked throughout the entire shipping process, including for example, transportation to local distribution warehouses, storage there, collection into shipping containers or other ULDs, transportation to destination warehouses, storage there, local transportation to the destination, and drop-off to recipient. Preferably, passive repeaters and additional RFID tags can be used to identify and track aggregate collections of cartons  120 . Also optionally, the recipient can utilize the RFID tagged cartons to maintain inventory and tracking. One of skill in the art will recognize this is particularly advantageous when the recipient engages in retail or wholesale sales of goods supplied by the customer. Further, the delivery company can use the cartons with integrated RFID tags for advertising, as the carton will be used throughout the manufacture, delivery and distribution chain as described above.  
         [0072]    An additional embodiment of the invention is shown in FIG. 16, wherein a modular RFID antenna system  130  of the invention is retrofitted into a trailer  132  for use with a conventional tractor-trailer. In a preferred embodiment of the invention, the antenna system  130  comprises modular antenna segments  134 , as described above, and is powered by external battery  136 . In an additional envisioned embodiment of the invention, the antenna system  130  is powered by the electrical or battery system of the tractor-trailer.  
         [0073]    Referring now to FIG. 17, the modular RFID antenna system  130  can also be retrofitted into a cargo truck  138 . In this embodiment, the antenna system  130  is preferably powered by an existing vehicle battery  140 .  
         [0074]    In the embodiments shown in FIGS. 16 and 17, the antenna system  130  communicates with items having RFID tags as they are loaded to and unloaded from trailer  132  or truck  138 , allowing accurate tracking of tagged items throughout the transport chain. In addition to trailers or trucks, the system can be used with any suitable transport vehicle.  
         [0075]    In yet another embodiment of the invention, a modular RFID antenna system  142  of the invention is installed at entrance to a building or warehouse  144 , such as at loading dock  146 . Utilizing such systems allows tracking of RFID tagged items when they are stored on a loading dock, for example, prior to warehousing or loading onto a transport device. Similarly, the positioning of antenna system  142  adjacent the entrance of a building or warehouse ensures that RFID tagged items will be tracked whenever it leaves or enters the building.  
         [0076]    Without departing from the spirit and scope of this invention, one of ordinary skill can make various changes and modifications to the invention to adapt it to various usages and conditions. As such, these changes and modifications are properly, equitably, and intended to be, within the full range of equivalence of the following claims.