RFID scanning system and shopping bag with integrated RFID loop antenna

A point of sale system and method are disclosed wherein a shopping bag has one or more RFID loop type antenna. An example system includes a bag holder for securing the shopping bag while items are placed in it. Multiple bag holders may be incorporated on a carousel, which can be rotated to move an empty bag to a filling station at the checkout counter, and to move filled bags to an open area for the customer or cashier to retrieve the filled shopping bags. An RFID reader in communication with the bag holder uses one of the RFID loop antennas to read the RFID tags on the items placed in the bag. In a shopping bag having more than one RFID loop antenna, the RFID system controller may monitor the impedance of each RFID loop antenna and dynamically select one of the RFID loop antennas on the shopping bag as a function of the impedances.

BACKGROUND

1. Field of the Invention

The present invention relates generally to retail point of sale systems, and more particularly to RFID scanning of retail goods.

2. Background of the Related Art

Point of sale (POS) systems are specialized computer systems used in retail environments for facilitating the checkout process, and which identify and account for items that a customer has selected for purchase. Modern POS systems typically include a POS terminal located at a checkout counter to facilitate the checkout process. A POS terminal typically includes a variety of user interface devices, such as a cash register, check/debit card/credit card reader, and a bar code scanner. The Universal Product Code (UPC) scheme is commonly used to uniquely identify items selected for purchase. The UPC scheme uses barcode symbology that has improved the speed and accuracy of checkout. The UPC scheme allows each item selected for purchase to be scanned in with an optical scanner, one item at a time, and cross-referenced with an electronic database containing price information for the associated item.

Various item-tracking solutions using radio frequency identification (RFID) tags have been proposed in an effort to provide even greater speed and accuracy than conventional UPC systems. RFID-based scanning systems typically involve an active scanning device, and a transponder in the form of an active, passive, or semi-passive RFID tag affixed to each item. RFID tags can be read from up to several meters away, and RFID scanners are capable of multi-directional reading, allowing RFID tracking systems to scan for multiple items in the vicinity of the scanner. Efforts to implement RFID-based scanning systems have included proposed ideas for scanning an entire shopping cart full of items at once in an effort to save time over individually scanning item barcodes. However, difficulties have arisen in obtaining an accurate accounting of shopping cart contents when scanning the entire shopping cart. For example, items near the center of a cart may not be reliably detected with an RFID scanner using existing technology.

BRIEF SUMMARY

An inventory tracking system and method are disclosed for facilitating the checkout of items with RFID tags. A disclosed example system describes a shopping bag having at least one RFID loop antenna along a perimeter of the shopping bag. The RFID loop antenna may make one or more passes along the perimeter. A bag holder secures the shopping bag with a shopping bag interface electrically connected with the at least one RFID loop antenna. A controller includes an RFID reader electrically connected with the shopping bag interface and configured to read RFID tags on items in the shopping bag using the at least one RFID loop antenna on the shopping bag. A plurality of the described bag holders may be provided on a carousel that allows for positioning a selected bag holder and shopping bag at a filling station adjacent a checkout counter. A disposable version of the shopping bag may have antenna loops formed from electrically conductive ink silk-screened onto the bag. In a shopping bag having multiple RFID loop antennas, the controller may sense the impedance of each antenna and dynamically select from among the available antennas according to the sensed impedances.

DETAILED DESCRIPTION

A point of sale system and method are disclosed wherein one or more RFID loop antenna is incorporated directly on a shopping bag, so that the contents of each shopping bag may be reliably scanned during checkout. Different examples of shopping bags are disclosed having various RFID loop antenna designs and various numbers of RFID loop antennas. An example system includes a bag holder for holding the shopping bag while items are placed in it. Multiple bag holders may be incorporated on a carousel, which can be rotated to move an empty bag to a filling station at the checkout counter, and to move filled bags to an open area for the customer or cashier to retrieve the filled shopping bags. The bag holder electrically interfaces with the one or more RFID loop antenna on the shopping bag. An RFID reader in communication with the bag holder uses one of the RFID loop antennas to read the RFID tags on the items placed in the bag. In a shopping bag having more than one RFID loop antenna, the RFID system controller may monitor the impedance of each RFID loop antenna and dynamically select one of the RFID loop antennas on the shopping bag as a function of the impedances. The proposed systems and methods reliably scan items selected for purchase, because the items may be scanned individually or in smaller quantities as they are placed in the shopping bag. While the system and method are discussed in the context of a grocery checkout, the disclosed concepts may be applied in any of a variety of retail environments.

FIG. 1is a perspective view of a shopping bag10for use with an embodiment of an RFID-based inventory tracking system disclosed herein. The shopping bag10is provided for conveniently carrying items selected for purchase, such as groceries or retail products that fit into the shopping bag10. The shopping bag10includes an opening14for receiving the items and subsequently removing the items from the shopping bag10. A pair of opposing handles11,12allow a user (e.g. a customer or cashier) to carry the shopping bag10and its contents by hand. When carrying the shopping bag10, the user may bring the opposing handles11,12together and place a hand through the handles11,12, which helps secure the contents of the shopping bag10and allows the weight of the shopping bag10and its contents to be supported from both handles11,12. The shopping bag10may be optimized as a single-use, “disposable” shopping bag using a lightweight, inexpensive material, such as a thin-walled plastic like polyethylene. A disposable version of the shopping bag10may be optimized to have enough strength and durability for a typical shopping trip, but with sufficiently low material-content to minimize the associated cost and environmental impact. Alternatively, a multiple-use version of the shopping bag may be optimized to have the strength and durability to be re-used for multiple shopping trips.

Though a shopping bag according to the disclosed principles may have any number of RFID loop antennas, a suitable shopping bag may have as few as one RFID loop antenna. In this embodiment, two RFID loop antennas L1, L2are formed on the shopping bag10for redundancy and to allow antenna selection based on impedance. The first RFID loop antenna L1is formed on an interior surface21of the shopping bag10. The second RFID loop antenna L2is formed on an exterior surface22of the shopping bag10to avoid crossing the first RFID loop antenna L1. Alternatively, an electrically insulating material may be applied so that both loops may be formed on the same surface (inner or outer) and cross in one or more locations without electrically contacting one another. For example, a first antenna can be formed on the bag10, and an insulating layer applied in locations where a second antenna is to cross the first antenna, before forming the second antenna on the bag10. Any number of RFID loop antennas may be constructed in a similar manner.

Referring again to theFIG. 2embodiment, each RFID loop antenna L1, L2is oriented along a perimeter of the shopping bag, so that the path of each RFID loop antenna L1, L2lies in a plane parallel or nearly parallel to a plane of the opening14of the shopping bag10. The term “loop” refers, in part, to the physical resemblance to a loop, even though a loop antenna may be slightly less than 360 degrees. The term “loop” may also refer to the fact that the loop antennas L1, L2form a complete circuit loop when interfaced with a bag reader, as disclosed below. This orientation of the antennas L1, L2near the opening14helps ensure that items placed in the shopping bag10pass through a field of the RFID loop antennas L1, L2. Each loop L1, L2extends along nearly the full perimeter (360 degrees) of the shopping bag10. In an alternative embodiment, each RFID loop antenna L1, L2may extend beyond 360 degrees, optionally making multiple passes around the perimeter of the shopping bag10, such as along a spiral or corkscrew type path. The RFID loop antennas L1, L2terminate at the handles11,12. Ends15,16of the first loop L1define a pair of spaced-apart electrical contacts on the first handle11, and ends17,18of the second loop L2define another pair of spaced-apart electrical contacts on the second handle12. These spaced-apart electrical contacts defined by the ends15,16and17,18of the RFID loop antennas L1, L2will be used to interface with an external RFID reader, as discussed below.

Each RFID loop antenna L1, L2may be secured to the respective surface21,22of the shopping bag10in any of a variety of ways. In one embodiment, the electrically conductive materials used in the antennas L1, L2may be separately formed, such as from a thin metallic wire or sheet, and subsequently affixed to the shopping bag10. However, a preferred way to form the antennas, particularly in a disposable version of the shopping bag10, is to print the antennas L1, L2on the shopping bag10using an electrically conductive ink. Various ink deposition technologies may be applied to form the RFID loop antennas L1, L2, such as silver ink or copper ink printing. It may also be possible to use an electronically conductive polymer or polymer composite. The antennas L1, L2may be formed, for example, by silk-screening the RFID loop antennas L1, L2onto a flat sheet of shopping bag material, and cutting a flat pattern from the shopping bag material and joining the flat pattern at the ends. Alternative antenna paths might be used when printing the antennas on a flat pattern so that the antennas L1, L2are not severed. The RFID loop antennas can be formed by silk-screening on an already-formed (three-dimensional) shopping bag. Alternatively, any silk-screening be performed on a flat sheet material before forming the shopping bag. The “flat pattern” for such a bag may have a pre-printed antenna and the bag may then be joined at the edges to ensure no breaks in electrical conductivity.

The dimensions of the RFID loop antennas L1, L2may be selected according to a particular application. For most applications, a line width “w” of between 1 to 2 mm is suitable. A line width of greater than 2 mm is generally unnecessary because the read range between an antenna on the perimeter of the shopping bag and the RFID tag passing through the RFID loop antenna is small. The thickness of the electrically conductive ink deposited on the shopping bag10is another dimensional parameter to be selected. In a disposable version of the shopping bag10, a very thin layer of ink without appreciable long-term durability may be suitable, since the shopping bags may be stored at a checkout and handled very little before the RFID scanning of the shopping bag contents is complete. The electrically conductive ink may even be printed in a crosshatching pattern rather than a solid line, to reduce the amount of ink required while maintaining continuous electrical conductivity along each RFID loop antenna L1, L2. This minimization of ink furthers a design goal of producing a disposable shopping bag with minimal cost and minimal environmental impact upon disposal. A stouter, multiple-use version of the shopping bag may include a thicker band of electrically conductive material in the antenna for increased antenna durability, whether the antenna comprises conductive ink or is separately formed. The increased durability of the multiple-use version also minimizes environmental impact by offsetting any increased material content with the ability to use the shopping bag multiple times in its life cycle.

FIG. 2is a perspective view of the shopping bag10ofFIG. 1, as secured to a shopping bag holder30in electronic communication with an RFID system controller40. Only a partial view of the antennas L1, L2are shown here, for ease of illustration; reference may be made toFIG. 1for details of a specific example embodiment of the RFID loop antennas L1, L2. The shopping bag holder30includes an opposing pair of support arms31,32that are used to suspend the shopping bag10above a base28. The shopping bag holder30includes an electronic bag interface34that electrically connects with the RFID loop antennas L1, L2. Generally, a bag interface for electrically connecting with an RFID loop antenna on a shopping bag may take a variety of different forms, such as a particular arrangement of electrical contacts or a particular type of electrical connector, for interfacing with corresponding electrical contacts or electrical connector on a shopping bag. By way of example, the shopping bag interface34in this particular embodiment of the shopping bag holder30includes a first pair of prongs35,36on the first support arm31and a second pair of prongs37,38on the second support arm32. As noted above, the exposed ends15,16of the first RFID loop antenna L1and the exposed ends17,18of the second RFID loop antenna L2act as respective pairs of electrical contacts on the shopping bag10. The first pair of prongs35,36may be electrically conductive, or have electrical contacts (seeFIG. 3), for engaging the exposed ends15,16of the first RFID loop antenna L1, and the second pair of prongs37,38may be electrically conductive or have electrical contacts that engage the exposed ends17,18of the second RFID loop antenna L2. Signal lines39extend from the prongs35,36,37,38to the RFID system controller40.

A supply of shopping bags10A may be stored in a compressed or unopened position on the bag holder30. Both handles11,12of each stored shopping bag10A are initially suspended from the first arm31by the first pair of prongs35,36. The stored shopping bags10are flattened and will not need their RFID loop antennas activated, nor actually electrically connected to the RFID system controller40. The particular shopping bag10to be filled may be opened by unhooking and moving the second handle12away from the first arm31toward the second arm32, and positioning the second handle12over the second pair of prongs37,38on the second arm32. The opened shopping bag10interfaces with the shopping bag interface34, whereby the ends15,16of the first RFID loop antenna11are in electrical connection with the prongs35,36of the first arm31, respectively, and the ends17,18of the second RFID loop antenna12are in electrical connection with the prongs37,38of the second arm32, respectively. Accordingly, the RFID loop antennas L1, L2on the opened shopping bag10are electrically connected to an RFID system controller40. The RFID system controller40is able to select one of the RFID loop antennas L1, L2and use the selected RFID loop antenna for reading the RFID tag25on each item24being placed in the shopping bag10. The RFID tag identifies product information about the item24, such as product type, brand, size, weight, and price.

FIG. 3is a partially-cutaway, front-facing elevation view of the shopping bag holder30ofFIG. 2.FIG. 3illustrates two alternative types of electrical contacts that may be used on the prongs35-38for interfacing with the loop antennas on the shopping bag10. Both pad type contacts71and puncture type contacts72are shown inFIG. 3, by way of example. However, only one of the two sets of contacts71or72may be selected for use in a practical embodiment. Pad type contacts71rely on the weight of the shopping bag10and its contents to urge the exposed ends of the loop antennas (seeFIG. 2) into electrical connection with the pad type contacts. Puncture type contacts72are used to instead puncture (i.e. pierce) the shopping bag10. Puncturing the shopping bag10somewhere along the loop antenna(s) near their ends ensures reliable electrical connection with the loop antennas. Puncturing the shopping bag10with a puncture type contact72also may be done to make contact with a loop antenna that is on an opposite surface of the shopping bag from the puncture type contacts72. The selected set of contacts71or72are electrically connected with the signal lines39that lead to the RFID system controller40, as discussed above. To prevent the supply of shopping bags10A from being inadvertently connected when stored, the handles11,12of the supply of shopping bags10A are held back from the electrical contacts71or72until a selected bag10is to be used. Then, the handles11,12of an individual bag10may be moved into position to make electrical connection with the signal lines39. The bags may be held back from the contacts71,72using any sort of retention mechanism, such as a retainer tab73. Alternatively, the bags10A may be held back from the contacts71,72by friction.

FIG. 4is a schematic diagram of an inventory tracking system50that includes the RFID system controller40. The RFID system controller40is located remotely to the shopping bag, such as at or near a checkout station. The RFID system controller40is electrically coupled to both RFID loop antennas L1, L2. A tuning circuit42and impedance sensor44are coupled to each RFID loop antenna L1, L2via the bag rack disclosed inFIG. 2. The tuning circuit42and impedance sensor44may be separate circuits for each antenna L1, L2or circuits shared by both antennas. The tuning circuit42and RFID loop antenna44are in communication with an RFID reader46. Control logic for the RFID system controller40may reside on the RFID reader46or may be distributed among more than one component of the RFID system controller40. The RFID reader is configured for reading an RFID tag25using a selected one or more of the two antennas L1, L2. Note that the two RFID loop antennas L1, L2shown side by side in the schematic diagram may be physically positioned one above the other as shown inFIGS. 1 and 2, with both RFID loop antennas L1, L2simultaneously within readable range of the same RFID tag25. The inventory tracking system50includes a remote host computing server (i.e. “remote host”)52. The remote host52includes a database of product information that can be cross-referenced with information from the scanned RFID tag25, and may accumulate data collected from each transaction.

Control logic is included, preferably within the RFID system controller40, for dynamically selecting one of the two antennas L1, L2for use in scanning the RFID tags25using the RFID reader circuit46. The RFID system controller40may select which antenna to use based, at least in part, on the impedances of the RFID loop antennas L1, L2. The target antenna impedance for each antenna is a design parameter, which may be a function of the electrically conductive antenna material, the antenna dimensions, and the particular antenna path and number of loops in each antenna. A target impedance of about 50 ohms for an opened shopping bag is within range of a useful RFID antenna impedance. The actual impedances of the RFID loop antennas L1, L2may deviate from their expected values, such as due to manufacturing tolerances in forming the shopping bag10. The actual impedance of the antennas measured by the impedance sensors44may also vary due to the flexible nature of the shopping bag10. For example, as the shopping bag10is handled, and particularly as items are placed into the shopping bag10, the shape and position of the shopping bag10may change, causing a change in the measured impedance values. An antenna may eventually fail due to fatigue if the shopping bag10is mishandled or used beyond its design life. Damage to an antenna short of fully severing the antenna may change the antenna impedance, and a complete severing of the antenna may render it unusable. Such damage may be sensed, for example, as an excessive or “infinite” impedance indicative of an open circuit. Thus, having two or more RFID loop antennas L1, L2also provides redundancy, by allowing one of the antennas to serve as a backup antenna in the event that another antenna fails.

Because the impedances of the RFID loop antennas L1, L2may vary, the RFID system controller40uses the impedance sensors44to dynamically measure the impedance of each RFID loop antenna44and to select the best antenna based on the currently measured impedance values. The RFID system controller40then uses the tuning circuit42to tune the RFID reader to match the measured impedance of the currently selected antenna L1or L2. In one implementation, the impedance values of the RFID loop antennas L1, L2are measured in serial fashion using the impedance sensors44, and the RFID system controller40dynamically selects and switches to the best antenna L1or L2for usage according to the sensed impedance values. In selecting which RFID loop antenna to use, the RFID system controller40may compare the measured impedances to a predetermined impedance threshold to determine the “quality” or usability of each antenna L1, L2. The threshold may have an upper limit and a lower limit. A simplified and lower cost impedance sensing circuit may simply detect an “out of tolerance” antenna impedance as one which is not currently between the upper and lower thresholds, without necessarily determining an actual impedance value. The RFID system controller40could be programmed with different impedance thresholds for different antenna designs, and select the impedance thresholds to be used according to the currently used antenna design.

FIG. 5is a plan view of a point of sale (POS) checkout60incorporating the inventory tracking system50ofFIG. 3and a shopping bag carousel62having a plurality of bag holders30A,30B,30C,30D of the type detailed inFIG. 2. A counter66is provided as a place for putting loose items removed from a shopping cart68, prior to bagging the items. A conveyor69is optionally provided to move the loose items toward the carousel62. A checkout terminal64facilitates the purchase of items selected by a shopper. The checkout terminal64includes hardware such as an electronic register for computing and displaying transaction information such as a list of scanned items, a description and price of the scanned items, and a purchase total. The checkout terminal64may also include common POS devices such as a cash drawer, a payment card reader, a receipt printer, and a coupon printer. The RFID system controller40(disclosed inFIG. 4) is positioned, by way of example, within the carousel62. Some components of the RFID system controller40may be located elsewhere, such as within the checkout terminal64. The remote host52may be located anywhere with a network connection, and is in electronic communication with the checkout terminal64. The RFID system controller40may be in direct or indirect electronic communication with either or both of the checkout terminal64and the remote host52. The checkout terminal64and the carousel62are both conveniently located for operation by a cashier, as in the case of a traditional cashier-supervised purchasing transaction, or by the customer, as in the case of a self-serve style checkout.

Four shopping bag holders are provided on the carousel62in this example, individually identified at30A,30B,30C, and30D. A different number of shopping bag holders may alternatively be included depending, for example, on the size of the shopping bags10and the size of the carousel62. A refillable supply of shopping bags may be provided at each bag holder30, hanging in a flat or compressed state from one of the two arms31,32. One of the bags10from the stored supply of shopping bags may be opened and supported from both arms31,32, as described above with regard toFIG. 2. The carousel62can be rotated to position any one of the shopping bag holders at a “fill station”70at one end67of the counter66.

FIG. 5shows a first shopping bag holder30A currently positioned at the fill station70. After placing one or more items in the shopping bag10in the first bag holder30A, the carousel40may be rotated (counterclockwise in this example) to position a next bag holder30B at the fill station70. The shopping bag10on the next bag holder30B may be opened at the fill station70or prior to being positioned at the fill station70. With the second bag holder30B positioned at the fill station70, one or more items may be placed in the opened shopping bag10of the second bag holder30B. Rotating the carousel62to advance the next second bag holder30B at the fill station70brings the previously filled shopping bag30A to an open area, where the filled shopping bag may be conveniently removed from the bag holder30A and optionally placed in the shopping cart68for transporting out of the store by the customer. The process may continue, each time advancing one of the bag holders30A-D on the carousel62having an empty bag to the fill station70, and advancing a filled bag out of the fill station70to be removed from the carousel62.

As the items are placed in the opened shopping bag10currently at the fill station70, an RFID loop antenna on the shopping bag10is used by the RFID system controller40to scan the RFID tags on the items. Scanning the RFID tags individually as they pass through the antenna loop(s) facilitates accurate scanning. However, each bag holds a sufficiently small quantity of items that the RFID tags may alternatively be scanned all at once after already having been placed in the shopping bag10. The identities of the scanned items are communicated to the remote host52, perhaps directly or via the checkout terminal64. The identities of the scanned items may be cross referenced with an item database at the remote host52to obtain product information about the scanned items. The product information, such as an item description and price, is then communicated back to the checkout terminal64, where the product information is selectively displayed and a sub-total of the cost may be computed.

An “active bag” may refer to a shopping bag10on the carousel62that has been opened for use, with bag handles attached to the conductive contacts on the bag holder arms. When the RFID Reader circuit senses an antenna connection to the bag holder via sensing an impedance in a predefined range, the shopping bag becomes active. An optional security feature entails detecting when a shopping bag is disconnected, and comparing the weight of the bag against an expected weight. The shopping bag10may be weighed, and the weight of the disconnected shopping bag may be compared against the expected weight based on the items inside the shopping bag. The expected weight may be computed based on item information from the remote host52. An indication of the difference between the weight and the expected weight may be output. For example, if the weight is within an expected weight range, a confirmation may be displayed. If the weight does not agree with the expected weight range, and particularly if the weight is substantially greater than the expected weight, then an alarm may be sounded or displayed that would alert store personnel to inspect the shopping bag10for any unscanned items that may not have been accounted for at purchase.

FIG. 6is a layered, perspective view of an alternative disposable shopping bag10B, wherein each RFID loop antenna L1, L2terminates at one end on one handle11and at the other end on the other handle12. For clarity, the loop antennas L1, L2are shown on separate layers, with the layers positioned one above the other, in an assembly-view fashion. The shopping bag10B may actually be manufactured as two separate layers (i.e. bag plies), with one antenna per bag ply, as shown. The two bag plies may then be joined, such as by bonding. Alternatively, the two antennas L1, L2may be formed on a unitary bag, in which case the illustrated layers are simply provided as a drawing aid to help the reader visualize the separate paths that each antenna L1, L2follows. In this embodiment, each loop antenna L1, L2follows a path around the perimeter of the shopping bag10B, terminating at one end on one handle11and at the other end on the other handle12. Each loop antenna L1, L2follows a path of more than one full loop (i.e. more than 360 degrees) around the perimeter of the shopping bag10B, to ensure continuity of the electromagnetic antenna loop field. An electrically insulating material may be applied in any locations where one antenna intersect another antenna, or where one of the antennas intersects itself. If the loop antennas L1, L2are formed on separate plies and the plies subsequently joined, the bag material, itself, may provide sufficient electrical insulation between the two antennas L1, L2.

For each RFID loop antenna L1, L2, there may be one active electrical prong on each support arm of the bag holder (a variation of the bag holder30shown inFIG. 2). Thus, completing a RFID loop antenna circuit in this embodiment requires opening the shopping bag10B to position one handle11on one arm of the shopping bag holder and the other handle on the other arm12of the shopping bag holder. This requirement of placing one handle11on one arm and the other handle12on the other arm may help the RFID controller in detecting whether the shopping bag10B is properly positioned on the bag holder30ofFIG. 2. This may also help avoid inadvertently energizing the RFID loop antennas L1, L2before the shopping bag10B is opened.

FIG. 7is a side view of another variation of the shopping bag10C incorporating donut-type contacts81,82at the ends15,16of the RFID loop antenna L1. The donut-type contacts81,82are also formed of electrically conductive ink. The prongs34,35pass through holes in the donut-type contacts81,82, which may have close tolerances to help ensure reliable electrical connection between pad-type contacts on the prongs34,35and the donut-type contacts81,82on the shopping bag10C. The weight of the suspended shopping bag10C may also provide a downward force against the prongs34,35to provide reliable electrical connection.

FIG. 8is a side view of an alternative bag holder30A incorporating spring clips91,92for securing the shopping bag10to the bag holder30A. Each handle11,12of the bag is “hooked” over the respective spring clip91,92. The spring clips91,92engage a portion of the RFID loop antennas L1, L2(schematically shown) to provide positive electrical engagement with the RFID loop antennas, as well as to provide a secure mechanical attachment of the bag10to the bag holder30. Electrical communication pathways (not shown) leading to the RFID reader are provided at the points of engagement between the spring clips91,92and the RFID loop antennas L1, L2.

In the above-described embodiments, the bag holders were located at POS checkout, such as on a carousel. Locating the bag holders at a POS checkout facilitates the checkout process by allowing the process to be monitored from a central location, where store personnel may be available to supervise and assist with the process. Locating the bag holders at the POS checkout also allows much of the hardware, such as the RFID system controller, to be hardwired in a fixed location. However, in an alternative embodiment, the described bag holder could be moved with the customer to allow items to be scanned while shopping. For example, in a “bag-as-you-go” embodiment, the RFID system controller and one or more bag holders may be mounted in a shopping cart, with portable power supplies and optional wireless store network connectivity.