Radio-frequency-based system for bulk reading RFID tags

Abstract

The invention relates to a reflective agitating device (1) that comprises a set of metallic reflective panels (2) distributed longitudinally for reflecting radiofrequency waves emitted by a radio frequency emitter. The set of reflective panels (2) comprises two or more reflective panels (2) positioned at different angles from one another with respect to a central longitudinal direction, each reflective panel (2) comprising at least one continuous surface. The invention also relates to a radio-frequency-based system for bulk reading tags, which comprises a reverberation chamber (5) and a reflective agitating device (1) like that defined, disposed inside the reverberation chamber (5).

Description

[0001] SYSTEM FOR MASSIVE READING OF RFID LABELS BY RADIO FREQUENCY

[0002] DESCRIPTION

[0003] Object of the invention

[0004] The present invention is in the technical field of electromagnetic waves, more specifically it is related to the propagation and reflection of electromagnetic waves, in closed environments, with the objective of allowing mass reading of labels that allow product identification.

[0005] The object of the invention is to define a product or device that allows improving the existing system configured to achieve mass reading of labels, in a simple and efficient manner.

[0006] Technical problem to be solved and background of the invention

[0007] RFID (Radio Frequency Identification) technology is a system that allows remote data stored on tags, cards, or transponders to be identified, stored, and transmitted using radio frequency. RFID technology aims to identify a card or tag through a reader, allowing data to be transmitted via the card and read by an RFID reader. The data transmitted depends on each application, but can include information about the composition, location, or characteristics of the product, or other more specific information.

[0008] The simplest configuration of a card or tag consists of a passive, battery-free component with an integrated circuit (chip) and an antenna, although there are also tags that have a built-in, lifetime battery. This type of tag allows information to be received and transmitted over different distances.

[0009] This technology is widely used in the distribution, packaging, and logistics sectors, as it allows for the rapid monitoring and control of orders and inventories for a large range of products, all distributed in different locations and configurations.

[0010] One of the main problems in these sectors arises when products are grouped in large batches or on pallets, making it inefficient to retrieve information on all the packaged items individually.

[0011] The state of the art offers several solutions for performing these readings of large batches of products, grouped on pallets, more quickly and efficiently.

[0012] One of these solutions is the well-known reverberation chambers equipped with multiple UHF RFID antennas. By inserting the entire pallet, the information provided by all the items can be read simultaneously. The reverberation chamber enhances the reading effect thanks to its shielded room configuration, where the absorbed electromagnetic energy is minimal. This low absorption results in very high field strength with moderate input power.

[0013] However, the disadvantage of using a reverberation chamber is that, in a cavity resonator, the spatial distribution of the electric and magnetic field strengths is not homogeneous, so standing waves can appear. This means that the field distribution is similar to that in a microwave oven.

[0014] This lack of homogeneity is a problem for mass reading of tags in a closed area, since the appearance of standing waves implies that there are areas in said area where the signal intensity is zero, thus affecting the reading of tags present in those areas.

[0015] Some well-known state-of-the-art solutions attempt to resolve the uncertainty generated by these areas of low or no signal intensity by installing a complex rotating structure on the pallet or container in the shape of an inverted "U" where the antennas are mounted, rotating it at high speed to achieve maximum reading efficiency. However, this solution is very expensive, and the results are not proportional to the complexity involved.

[0016] Therefore, a simple and efficient solution for mass label reading in reverberation chambers is required in the current state of the art. This solution improves the product reading process, preventing the creation of spaces where reading is inefficient or impossible. Description of the invention

[0017] The present invention offers an alternative solution to those currently known to take advantage of the benefits of a reverberation chamber in the mass reading of RFID tags, but guaranteeing high reading efficiency by solving the field homogeneity problems described in the background of the invention.

[0018] This alternative solution consists of a reflective shaker device comprising a set of reflection panels, which comprise a metallic material, distributed along a central longitudinal direction, said reflection panels configured to reflect radiofrequency waves emitted by a radiofrequency transmitter. The set of reflection panels comprises two or more reflection panels; where at least two of these reflection panels are oriented at different angles to each other, with respect to the central longitudinal direction, each reflection panel comprising at least one continuous surface.

[0019] In this way, the reflector shaker device of the present invention creates multi-path reflections of the waves emitted by the emitter, reducing the problematic lack of homogeneity described in the background, and said device can be located inside a reverberation chamber, as it is a modular element that can be installed inside said chamber, or moved around said interior by means of moving means, such as a base with wheels.

[0020] In one embodiment, the reflective shaker device comprises at least one support bar attachable to an external support, where each of the panels in the set of reflective panels is connectable or attachable to the support bar, and where the support bar extends in the central longitudinal direction. The external support may be a floor, a wall, or a structural element to which it rests or is attached.

[0021] Non-preferably, the device may lack a support bar, with all the panels joined together, forming a skeleton or frame of the device, but the support bar provides a support structure on which the panels can rest, allowing them to have a reduced thickness, in the form of a sheet metal, configured to favor the reflection of the waves from the transmitter.

[0022] In one embodiment, each of the reflection panels comprises a means for attaching to the support bar, where said attachment means is selected from a rigid attachment means and a movable attachment means, where said attachment means can be adjustable. That is, the reflection panels can be connected to the support bar in a rigid manner, comprising welds, screws, rivets, or means that allow a rigid connection, such as with flanges, or tightening systems, but which, at the same time, allow their inclination or position with respect to the bar to be modified when desired by the user. That is, they can have some element, means, or characteristic that, while maintaining the union of the parts, allows their position or angle to be modified. A plastic deformation of the panels, with respect to their union with the support bar, can be considered as one of said means.

[0023] Likewise, the reflection panels may also be connected to the support bar by means of mobile, sliding or articulated joints, such as clearance adjustments, which allow said panels to rotate or move with respect to the bar when subjected to some type of load, also having means that allow their position and inclination with respect to the bar to be modified, in order to adjust the orientation of the panels to the needs of the user.

[0024] In one embodiment, each reflection panel in the set of reflection panels comprises an adjustable attachment to the support bar, each reflection panel comprising at least one slot fitted to a projection on the support bar. In this embodiment, the position of the panel relative to the bar can be adjusted, and the inclination between them can also be adjusted, such that, once in the position desired by the user, the attachment can be tightened to prevent the panel from shifting or rotating when the shaking device is in use.

[0025] In one embodiment, the support bar has the shape of a metal profile with a rectangular section, preferably square.

[0026] In an embodiment dependent on the two previous embodiments, each reflection panel comprises a rectangular central through opening, crossed by the metal profile of the support bar, said bar comprising a pair of projections corresponding to a pair of slots of each reflector panel included in the device.

[0027] In one embodiment, the reflector shaker device comprises rotation means configured to rotate at least one of the reflection panels relative to a rotation axis, which includes the central longitudinal axis. That is, in one embodiment, the panels can be fixed and immobile relative to the space in which they are located, but in the preferred embodiment, the device allows the panels to rotate relative to a longitudinal axis in a hinged manner. This rotation can be carried out in many different ways, allowing all the panels to rotate together or independently. This feature allows the panels to increase their reflection of the waves emitted by the transmitter. Preferably, said rotation means comprise at least one motor.

[0028] In one embodiment, the rotation means are located on the support bar and are configured to rotate at least one of the reflection panels relative to the external support to which the support bar is attached. That is, all or only some of the device's panels can rotate, depending on their configuration.

[0029] In one embodiment, the set of reflection panels is formed by a single sheet metal piece with folds at one end of each of said reflection panels, where each reflection panel is defined by two consecutive folds. Preferably, said folds arrange the reflection panels in an orientation that places them perpendicular to each other.

[0030] In another embodiment, the set of reflection panels is formed by a plurality of independent pieces distributed in a central longitudinal direction. These panels can be connected to each other by some end portions or by the support bar.

[0031] In one embodiment, the rotation means are configured to rotate the set of reflection panels, either jointly or in unison, relative to the external support to which the support bar is attached. That is, all the panels can rotate, forming a single rotating element.

[0032] In one embodiment, the rotation means are configured to rotate the set of reflection panels independently of each other with respect to the external support to which the support bar can be attached. That is, if the panels do not form a single body, they can be attached to the support bar independently and, therefore, can also rotate independently, depending on the user's needs regarding the wave refraction index. In one embodiment, each reflection panel comprises two or more surfaces angled between them, said surfaces comprising different inclinations with respect to the central longitudinal direction. Said surfaces are preferably flat, although they could be curved if it is found that said curvature improves or can improve wave reflection. Each additional inclination of the reflection panel increases the reflection directions bounced by said panel.

[0033] In one embodiment, each reflection panel comprises at least a rectangular area with a length, width, or area equal to or greater than 0.35 meters. This size is considered the minimum suitable for the panel to correctly reflect the received wave.

[0034] In addition to the device, the described invention also comprises a system for mass reading of radiofrequency tags, comprising a reverberation chamber and a reflective shaker device, as defined in any of the previous embodiments, located inside the reverberation chamber. The term "tag" should be understood as the term defined in the background, also known as cards or "tags."

[0035] This system integrates a new, non-invasive, enhancement module that fits into the current structure in a versatile and adaptable manner to meet the desired needs.

[0036] In one embodiment, the system for mass reading of radio frequency tags comprises a radio frequency transmitter comprising a transmitting antenna located inside the reverberation chamber; and a radio frequency receiver comprising a receiving antenna located inside the reverberation chamber.

[0037] In one embodiment, the reverberation chamber is configured to receive pallets of products, said products comprising passive RFID tags. That is, the reverberation chamber must be sized appropriately for the quantity of products to be placed inside.

[0038] In one embodiment, the support bar of the reflector shaker device is fixed to a floor or a ceiling of the reverberation chamber, said support bar being arranged in a vertical orientation with respect to the floor of said reverberation chamber.

[0039] In one embodiment, the support bar of the reflector shaker device is fixed to a side wall of the reverberation chamber, said support bar being arranged in a horizontal orientation with respect to a floor of said reverberation chamber.

[0040] In one embodiment, the system for mass reading of radio frequency labels comprises two reflective shaker devices as defined in any of the described embodiments, said devices located inside the reverberation chamber.

[0041] In one embodiment, the support bars of the two reflector shaker devices are fixed to a floor or a ceiling of the reverberation chamber, each of the reflector shaker devices being located at an opposite end portion of the interior of the reverberation chamber.

[0042] In other embodiments, one device may be arranged in a vertical position and another in a horizontal position, in different parts of the reverberation chamber.

[0043] As previously stated, the mass radio frequency tag reading system is intended to read or encode tags. In the case of encoding, since transmitter-receiver communication requires slightly more data traffic, it takes longer, so the shaking device aims to reduce these times. Due to the size of the station, the use of between four and eight antennas connected to the RFID encoder-decoder device has been analyzed and tested.

[0044] Description of the figures

[0045] To complete the description and to help better understand the characteristics of the platform, a set of drawings is attached to this descriptive report, as an integral part thereof, in which the following has been represented for illustrative and non-limiting purposes:

[0046] Figure 1 shows a perspective view of an embodiment of the reflector shaker device, where it can be seen that all the reflection panels of the set of panels form part of a single body, the panels being folded at an angle close to 90 degrees, and all of them being rigidly fixed to three support bars.

[0047] • Figure 2 shows a perspective view of one embodiment of the reflector shaker device, where it can be seen that all the reflection panels in the panel assembly are independent, i.e., they are comprised of the same number of bodies. Each of these panels comprises three flat surfaces, inclined relative to each other.

[0048] • Figure 3 shows a perspective view of an embodiment of the reflector shaker device, where it can be seen that all the reflection panels of the panel set comprise different independent bodies, but arranged to form a continuous accordion-shaped structure, the panels being folded at an angle close to 90 degrees between them, and 45 degrees with the support bar; and each panel and said support bar comprising an inclination adjustment comprising a slot in each panel and a corresponding projection on the bar.

[0049] • Figure 4 shows a detailed perspective view of the reflection panel shown in Figure 3.

[0050] • Figure 5 shows a schematic elevation view of the system described for mass reading of radio frequency labels, in which a reverberation chamber can be seen, with a vertically oriented reflector shaker device inside, two transmitting antennas, two receiving antennas, as well as a pallet with products between said antennas.

[0051] • Figure 6 shows a schematic plan view of the scheme represented in Figure 3, showing the reverberation chamber, the reflector-shaker device, as well as the transmitting and receiving antennas.

[0052] • Figure 7 shows a diagram similar to that shown in Figure 5, showing a reverberation chamber in plan, the system shown comprising two reflector shaker devices, one of them in horizontal orientation and the other in vertical orientation.

[0053] • Figure 8 shows a diagram similar to that shown in Figure 4, showing a reverberation chamber in plan, the system shown comprising two reflector shaker devices, each located at an opposite corner of the reverberation chamber.

[0054] List of numerical references shown in the figures: 1 Reflector shaking device

[0055] 2.- Reflection panel / s 21.- Slot

[0056] 3.- Support bar / s

[0057] 4.- Rotation media

[0058] 5.- Reverberation chamber

[0059] 6.- Transmitting antenna

[0060] 7.- Receiving antenna

[0061] 8.- Pallet / s

[0062] 9.- Protective screen

[0063] Preferred description of the invention

[0064] The first part of the invention is shown in Figures 1 to 3, where a reflector shaker device (1) can be seen comprising a series of reflection panels (2), made of metallic material, preferably steel or aluminum, distributed in a central longitudinal direction, determined by a support bar (3) that supports said reflection panels (2). In fact, in Figure 1, it can be seen how the reflector shaker device (1) comprises up to three support bars (3) fixedly connected to four reflection panels (2), these formed by a single piece or folded laminar body. On the other hand, Figure 2 shows only one support bar (3) fixed to six reflection panels (2) at some lateral end parts of said panels.Furthermore, in the embodiment shown in Figure 2, it can be seen how the reflection panels (2) each comprise three flat surfaces, inclined between them, increasing, with this arrangement, the capacity to reflect the waves.

[0065] Figure 3 shows another embodiment, considered to be preferred, said embodiment comprising a support bar (3) assembled to eight reflection panels (2), these being arranged continuously, like an accordion, inclined approximately at 90° between them, and at 45° with the support bar (3). Each of these reflection panels (2) are assembled to the support bar (3) by means of an adjustable joint comprising two slots (21), as shown in Figure 4, and the corresponding projections, on the support bar (3), for each reflection panel.

[0066] These reflection panels (2) allow radio frequency waves emitted by a radio frequency transmitter to be reflected through a transmitting antenna (6), creating multi-path reflections that reduce the problematic lack of homogeneity exposed in the background, this reflecting shaker device (1) being installed inside a reverberation chamber (5).

[0067] Given the different possible configurations of the reflector shaker device (1), the means of joining the reflection panels (2) to the support bar (3) are very wide. They can be joined by rigid or articulated joints, even mobile ones, in order to allow the position and / or orientation of the reflection panels (2) to be modified with respect to the support bar (3) in order to obtain an appropriate orientation to improve the efficiency of the device.

[0068] In addition to the aforementioned connecting means between the reflection panels (2) and the support bar (3), which allow the orientation and position of the reflection panels (2) to be modified, the reflector shaker device (1) also comprises, in its preferred embodiment, rotation means (4) configured to rotate, with respect to an axis of rotation, at least one of the reflection panels (2). Preferably, these rotation means also comprise a motor that performs the rotation movement.

[0069] In Figure 1 it can be seen that these rotation means (4) are located at the lower end of the support bar (3), where said support bar (3) rests on the floor, also comprising movement means in the form of wheels. These rotation means (4) allow the set of reflection panels (2) to be rotated in unison or together, as a single element. This rotation can be carried out at the same time as the reflector shaker device (1) is being used, in a reverberation chamber (5), in order to improve the reflection capacity of the device.

[0070] On the other hand, Figure 2 shows different rotation means (4), rigidly connected to the flooring and the ceiling of the reverberation chamber, preventing its movement, but allowing the rotation of the reflection panels (2), also jointly.

[0071] In Figure 3, it is shown that said rotation means comprise an electric motor at a lower end of the support bar (3).

[0072] Given the configurations described, it would be possible for the reflection panels (2) to be rotated individually. In this way, the configuration of the device described makes it possible for the reflection panels (2) to be moved to different orientations to achieve different boundary conditions. Advantageously, this produces a continuous and massive reflection of the waves, surprisingly multiplying the reading capacity of the system, which, unlike the state of the art, makes it unnecessary to move the antennas (6, 7) and they can remain fixed.

[0073] For the specific design of the reflector shaker device (1) of the present invention, the following wave characteristics are taken into account:

[0074] - Passive RFID: This technology uses frequencies between 860 MHz and 960 MHz.

[0075] MHz, that is, its wavelength varies from 0.35m to 0.31m respectively.

[0076] - The most well-known microwaves are usually located at 2.4 GHz, being in the E Band

[0077] (WIFI, microwave ovens...), with a wavelength of 0.125 m.

[0078] - Acoustic waves: audible from 20 to 20kHz, with wavelengths from 17.15m to 0.017m.

[0079] That is, given the application conditions mentioned above, and for an obstacle to block (or reflect) a signal, its size must be comparable to the signal's wavelength. Thus, in UHF RFID, obstacles must be comparable in size to 0.35 m. Half the wavelength of A / 2 is acceptable as a minimum.

[0080] Therefore, when working with UHF RFID, the maximum wavelength is 0.35 m, so with a reflector shaker device (1) it must have reflection panels (2) comprising at least one plane of 0.35 m in length, to obtain effective reflections.

[0081] Considering that the more multi-path reflections there are, the more homogeneous the field of the reverberation chamber (5) will be, the use of the reflector shaker device (1) like the one of the present invention is especially suitable, since it allows a greater reflection capacity than with the current existing devices.

[0082] The other part of the invention comprises the system for mass reading of radiofrequency labels, which comprises the reverberation chamber (5), and a reflector shaker device (1) as described, located inside the reverberation chamber (5).

[0083] The complete installation comprises an electromagnetic cavity defined by the interior of the reverberation chamber (5), which includes inside the reflector shaker device (1) to interact with the transmitting antenna(s) (6) and with the receiving antenna(s) (7), thus achieving a uniform field area around the set of products that are intended to be read grouped on the pallet (8).

[0084] Compared to the non-homogeneous distribution, the distribution resulting from introducing the “leaf” reflector agitator device (1) into the reverberation chamber (5) is much better distributed, clearly improving homogeneity.

[0085] Some of the possible embodiments of the system for mass reading of radio frequency labels with the reflective shaker device (1) are those shown in the diagrams in figures 5 to 8.

[0086] In a first embodiment of the invention, as shown in Figures 5 and 6, the system comprises a reflector shaker device (1) (also known as a mode shaker) in a vertical position, located next to a pallet station (8). This is the preferred option given its simplicity and good performance.

[0087] In a second embodiment, as shown in Figure 8, the system comprises two vertical reflector shaker devices (1) located next to the pallet station (8), each of these devices being in opposite corners of the reverberation chamber (5).

[0088] In a third embodiment, as shown in Figure 7, the system comprises two reflector agitator devices (1), one oriented in a vertical position and the other in a horizontal position, both together in the pallet station (8).

[0089] The chosen configuration depends on the characteristics of the rest of the elements, such as the labels to be read, the content and size of the pallet (8) or the technical characteristics of the transmitting antennas (6) and the receiving antennas (7) that must be located inside the reverberation chamber (5).

[0090] In conclusion, the reflective structure of the present invention (shaker) amplifies the reading capacity of RFID tags when inserted into a Faraday cage enclosure. Thus, the pallet containing the goods to be read is introduced into this radio-tight enclosure, and the tags are read efficiently throughout the entire enclosure.

Claims

CLAIMS 1.- Reflector shaking device (1) characterized in that it comprises: - a set of reflection panels (2), comprising a metallic material, distributed along a central longitudinal direction, said reflection panels (2) configured to reflect radio frequency waves emitted by a radio frequency transmitter; where the set of reflection panels (2) comprises two or more reflection panels (2); where at least said two reflection panels (2) are oriented at different inclinations between them, with respect to the central longitudinal direction, each reflection panel (2) comprising at least one continuous surface. 2.- Reflecting shaker device (1), according to the previous claim, comprising at least one support bar (3) attachable to an external support, where each of the panels (2) of the set of reflection panels (2) are connectable to the support bar (3), and where the support bar (3) comprises the central longitudinal direction. 3.- Reflective shaking device (1), according to the previous claim, where each of the reflection panels (2) comprises a means of fixing to the support bar (3), where said fixing means is selected between a rigid fixing means and a mobile fixing means, where said fixing means, rigid or mobile, are adjustable. 4.- Reflector shaker device (1), according to the previous claim, wherein each reflection panel (2) of the set of reflection panels (2) comprises an adjustable fixing with the support bar (3), each reflection panel (2) comprising at least one slot (21) adjusted to a projection included in the support bar (3). 5.- Reflector shaker device (1), according to any of the preceding claims, wherein the reflector shaker device (1) comprises rotation means (4) configured to rotate, with respect to a rotation axis comprising the central longitudinal direction, at least one of the reflection panels (2) of the set of reflection panels (2). 6.- Reflector shaker device (1), according to claim 3 or 4 and claim 5, wherein the rotation means (4) are located on the support bar (3), and are configured to rotate at least one of the reflection panels (2) with respect to the support. exterior where the support bar (3) is attached. 7.- Reflective shaking device (1), according to any of the previous claims, where the set of reflection panels (2) is formed by a single sheet metal piece with folds at one end of each of said reflection panels (2), where each reflection panel (2) is defined by two consecutive folds. 8.- Reflective shaking device (1), according to any of claims 1 to 6, wherein the set of reflection panels (2) is formed by a plurality of independent pieces distributed in a central longitudinal direction. 9.- Reflective shaker device (1), according to claim 6 and any of claims 7 or 8, wherein the rotation means (4) are configured to rotate the set of reflection panels (2) together with respect to the external support to which the support bar (3) can be attached. 10.- Reflecting shaker device (1), according to claims 6 and 8, where the rotation means (4) are configured to rotate each of the reflection panels (2), independently of each other, with respect to the external support to which the support bar (3) can be attached. 11.- Reflecting shaker device (1), according to claim 8, wherein each reflection panel (2) comprises two or more surfaces angled between them, said surfaces comprising different inclinations with respect to the central longitudinal direction. 12.- Reflecting shaker device (1), according to any of the preceding claims, wherein each reflection panel (2) comprises at least one rectangular area with a length equal to or greater than 0.35 meters. 13.- System for mass reading of labels by radio frequency, characterized in that it comprises a reverberation chamber (5), and a reflector shaker device (1) as defined in any of claims 1 to 11, located inside the reverberation chamber (5). 14.- System for mass reading of labels by radio frequency, according to the claim above, comprising a radio frequency transmitter comprising a transmitting antenna (6) located inside the reverberation chamber (5); and a radio frequency receiver comprising a receiving antenna (7) located inside the reverberation chamber (5). 15.- System for mass reading of labels by radio frequency, according to any of claims 13 to 14, wherein the reverberation chamber (5) is configured to receive pallets (8) of products, said products comprising passive RFID labels. 16.- System for mass reading of labels by radio frequency, according to claim 2 and any of claims 13 to 15, wherein the support bar (3) of the reflector shaker device (1) is fixed to a floor or to a ceiling of the reverberation chamber (5), said support bar (3) being arranged in a vertical orientation with respect to the floor of said reverberation chamber (5). 17.- System for mass reading of labels by radio frequency, according to claim 2 and any of claims 13 to 15, wherein the support bar (3) of the reflector shaker device (1) is fixed to a side wall of the reverberation chamber (5), said support bar (3) being arranged in a horizontal orientation with respect to a floor of said reverberation chamber (5). 18.- System for mass reading of labels by radio frequency, according to any of claims 13 to 17, comprising two reflector shaker devices (1) as defined in any of claims 1 to 12 located inside the reverberation chamber (5). 19.- System for mass reading of labels by radio frequency, according to claims 16 and 18, where the support bars (3) of the two reflector shaker devices (1) are fixed to a floor or to a ceiling of the reverberation chamber (5), each of the reflector shaker devices (1) being located in an opposite extreme part of the interior of the reverberation chamber (5). 20.- System for mass reading of labels by radio frequency, according to any of claims 13 to 19, where each reflector shaking device (1) located inside the reverberation chamber (5) comprises a protective screen (9).

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