RFID antenna

Abstract

An RFID reader antenna configured to extend a reading range of an antenna region comprises two or more antenna portions around a receiving zone for receiving a tagged item. The respective antenna portions are provided along the receiving zone thereby extending the reading range of the RFID reader antenna within the receiving zone. An RFID reader antenna is configured to form an array of antenna regions, each antenna region comprising a plurality of antenna portions around a receiving zone for receiving a tagged item. The respective antenna portions are arranged along the receiving zone thereby extending a reading range of the RFID reader antenna within the receiving zone.

Description

RFID AntennaTechnical Field

[0001] The present disclosure broadly relates to inventory tracking and identification and, more particularly, to an RFID reader antenna and an RFID system for tracking tagged items.Background

[0002] Radio-frequency identification (RFID) is a wireless identification technology that can be used to track items, for example for inventory tracking. Data is electronically stored on a tag that is attached to an item, and the data is readable by an RFID reader in order to identify, locate, and / or track the tagged item. When the antenna of the RFID reader is powered, the electromagnetic field generated by the reader antenna is able to transfer energy to the antenna of an RFID tag when the two antennas couple. Coupling activates the tag antenna so that the data on the tag can be accessed by the RFID reader.

[0003] The relative distance and the relative orientation of the two antennas are important factors in order for the reader and tag antennas to couple well enough to generate enough power in the tag to transmit the data to the reader effectively. In applications where the distance and orientation between the reader and tag antennas are variable, unpredictable, and / or cannot always be controlled, the operation of the RFID system is compromised with respect to accuracy and efficiency.

[0004] For these types of applications it can be challenging to design an RFID reader that is able to operate with acceptable accuracy while keeping the costs low. For example, the reader may include several antennas positioned in many places so that it is possible to track RFID tags in several places, and / or high RFID reader antenna power may be used, and / or variable RFID reader antenna power maybe used for one or moreof the reader antennas, etc. But such solutions add complexity and hence cost to the resulting RFID system.

[0005] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.Summary

[0006] An example of an RFID tracking system where the relative positioning of the RFID tags and the RFID reader antenna is variable, is a test tube holder that has one or more RFID reader antennas associated with the holder, and an RFID tag is applied to the test tubes using a sticker with a tag antenna. The test tubes may have varying sizes and / or lengths, the tag stickers that incorporate tag antennas may be of differing sizes and / or shapes, and the tag stickers (being applied by a user, and thus subject to human error and / or variation) may be positioned anywhere along the length of the test tubes. As a result, the operation of the RFID reader is dependent on both the size of the test tube and the position of the tag sticker; if the coupling between the reader antenna and the tag antenna is compromised, the accuracy of the reader is also compromised.

[0007] In one aspect there is provided an RFID reader antenna configured to form an array of antenna regions, each antenna region comprising a plurality of antenna portions around a receiving zone for receiving a tagged item, wherein the respective antenna portions are arranged along the receiving zone thereby extending a reading range of the RFID reader antenna within the receiving zone.

[0008] The RFID reader antenna may comprise a single antenna coil shaped to form the array comprising a plurality of antenna regions.

[0009] The receiving zone may have a first end and a second end, wherein the first end is a receiving end for receiving the tagged item, and wherein each antenna region surrounds a length of the receiving zone extending between the first end and the second end.

[0010] The tagged item may comprise a passive RFID tag with an RFID tag antenna coil at an outer wall or a perimeter of the item.

[0011] One or more of the antenna portions may comprise one or more curved parts to form a ring shape around the receiving zone so that each antenna portion operates like an antenna coil when the RFID reader antenna is activated.

[0012] The plurality of antenna portions of an antenna region may be spaced apart longitudinally around the receiving zone.

[0013] The RFID reader antenna may comprise two or more antenna zone arrays, each antenna zone array defining an antenna coil layer around a perimeter of the array of antenna regions; comprising two halves, one on either side of the array of antenna regions; and conductively connecting to at least one of a subjacent antenna zone array, and a superjacent antenna zone array.

[0014] In another aspect there is provided an RFID system for tracking tagged items, each item having an RFID tag with a tag antenna coil, the system comprising: an RFID reader; and an RFID antenna arrangement comprising: an array of antenna regions, each antenna region defined by a plurality of coaxially arranged antenna coils, each antenna coil comprising one or more curved parts to form a ring shape around a respective antenna region, wherein the RFID reader is configured to create an extended magnetic flux by activating the antenna arrangement to generate, by the plurality of coaxially arranged antenna coils, a cascading magnetic flux fringe that is couplable with a tag antenna coil of a tagged item positioned relative to or moving along an axis of a respective antenna region. The coaxially arranged antenna coils may be equi diametrical.

[0015] One or more of the antenna regions may comprise a plurality of antenna portions around a receiving zone for receiving a tagged item.

[0016] The plurality of coaxially arranged equi diametrical antenna coils may comprise antenna portions arranged along each antenna region. In some embodiments, the antenna coils may not be equidiametrical, for example depending on the configuration of the container, and / or of the receiving zone, and / or depending on the shape of the item. Similarly, in some embodiments the antenna coils may not be coaxially arranged, but may instead be arranged relative to one another in a different way, for example depending on the configuration of the container, and / or of the receiving region, and / or depending on the shape of the item.

[0017] One or more of the equidiametrical antenna coils may comprise one or more discontinuous curved parts to form a ring shape around the respective antenna region.

[0018] In another embodiments there is provided an RFID reader antenna configured to extend a reading range of an antenna region, the RFID reader antenna comprising two or more antenna portions around a receiving zone for receiving a tagged item, wherein the respective antenna portions are provided along the receiving zone thereby extending the reading range of the RFID reader antenna within the receiving zone. The antenna portions may abut one another or may be spaced apart along the receiving zone.

[0019] An RFID antenna arrangement may comprise two or more RFID reader antennas that are electrically connected to one another to form a series array of RFID reader antennas, each RFID reader antenna associated with a respective receiving zone and a respective reading range.

[0020] The two or more antenna portions may be layered to form a helical shape. Where an RFID antenna arrangement comprises such helical coils, each associated with an antenna reading zone and a respective receiving region, this allows for a relatively simple modular arrangement to facilitate increasing and / or decreasing the number ofreceiving zones. In other words, in a container that comprises container sections, each section with a respective helical coil antenna, such sections (together with their associated coil antennas) may be removed or added simply by electrically disconnecting or connecting a coil from or to the end of the array.

[0021] The RFID reader antenna may comprise an array of antenna layers that are layered along and about an array of receiving zones to extend a reading range of each receiving zone, wherein each antenna layer comprises a plurality of antenna portions electrically connected to one another within their layer, and wherein the plurality of antenna portions extend about the array of receiving zones.

[0022] These and other aspects and features will now become apparent to those skilled in the art upon review of the following description of specific non-limiting embodiments in conjunction with the accompanying drawings.Brief Description of Drawings

[0023] The detailed description of illustrative and non-limiting embodiments will be more fully appreciated when taken in conjunction with the accompanying drawings in which:

[0024] Figure l is a schematic representation of an embodiment of an RFID reader antenna.

[0025] Figure 2 is a schematic representation of magnetic field lines from a reader antenna.

[0026] Figure 3 shows a perspective and a side view of a tagged item with an RFID tag.

[0027] Figure 4 is a schematic representation illustrating the alignment of a tagged item and a reader antenna coil.

[0028] Figure 5 is a schematic representation of the magnetic field lines produced by a reader coil.

[0029] Figure 6 illustrated the magnetic field line produced by a reader coil relative to a tag antenna on an item positioned above the reader coil.

[0030] Figure 7 is top view schematic representation of the radial magnetic field produced by a reader antenna.

[0031] Figure 8 is top view schematic representation of the radial magnetic field of Figure 7 relative to the RFID tag of a tagged item.

[0032] Figure 9 illustrates the alignment of a tagged item and a reader antenna coil.

[0033] Figure 10 shows a non-limiting embodiment of a reader antenna coil having concentric coil turns.

[0034] Figure 11 is a schematic representation of a non-limiting embodiment of an array of reader coils.

[0035] Figure 12 shows another non-limiting embodiment of an array of reader coils.

[0036] Figure 13 is a schematic representation of an embodiment of an RFID reader antenna.

[0037] Figure 14 is an embodiment of an item holder with an RFID reader antenna therein.

[0038] Figure 15 is a schematic representation of an antenna arrangement configured to receive a tagged item within a receiving zone.

[0039] Figure 16 is a schematic representation of the antenna arrangement of Figure 15 positioned below a tag antenna on a received item.

[0040] Figure 17 is a schematic representation of the antenna arrangement of Figure 15 coupling with a tag antenna.

[0041] Figure 18 shows an embodiment of an RFID reader antenna.

[0042] Figure 19A is a schematic representation of an embodiment of an antenna arrangement that extends the reading range that couples with a tag placed low on an item.

[0043] Figure 19B illustrates the antenna arrangement of Figure 19A coupling with a tag placed high on an item.

[0044] Figure 20A shows an embodiment of an antenna coil layer.

[0045] Figure 20B shows an embodiment of an RFID reader antenna.

[0046] Figure 20C shows an embodiment of an RFID reader electrically connected to the RFID reader antenna of Figure 20B.

[0047] In the drawings, like reference numerals designate similar parts.

[0048] The drawings are not necessarily to scale and may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details that are not necessary for an understanding of the embodiments or that render other details difficult to perceive may have been omitted.Detailed Description

[0049] Reference will now be made in detail to various non-limiting embodiments of methods and systems that use RFID to track tagged items. It should be understood that other non-limiting embodiment s), modifications and equivalents will be evident to one of ordinary skill in the art in view of the non-limiting embodiment s) disclosed herein and that these variants should be considered to be within scope of the appended claims.

[0050] Furthermore, it will be recognised by one of ordinary skill in the art that certain structural and operational details of the non-limiting embodiment(s) discussed hereafter may be modified or omitted (i.e. non-essential) altogether. In other instances, well known methods, procedures, and components have not been described in detail.

[0051] In Figure 1 of the drawings, an RFID reader antenna 100 is configured to form an array 102 of antenna regions 110. Each antenna region 110 comprises a plurality of antenna portions 112 around a receiving zone 114 for receiving a tagged item 116. Each item 116 has an RFID tag 118 with an RFID tag antenna coil 119.

[0052] The receiving zone may be, for example, in the form of a container, a section of a container, a holder, or the like. The antenna portions each effectively form a ring or ring-like shape around a circumference of a respective receiving zone, so that an item placed into the container or holder will fit into and / or be located and / or held within a receiving zone, and thus also be placed and / or positioned within the ring shape of the various antenna portions. The antenna portions may be stacked, spaced, spread, or otherwise provided along and around at least a part of the length of the receiving zone. The antenna portions that are provided relative to the same receiving zone are aligned relative to one another and relative to the receiving zone in such a way that a tagged item moving into, out of, or otherwise through or along the receiving zone will move through one or more of the aligned antenna portions.

[0053] Typically, the tagged item 116 has a passive RFID tag 118, and the RFID tag antenna coil 119 is positioned to be at an outer wall or a perimeter of the item. Forexample, the item may be a test tube, a vial, a bottle, or the like, and the RFID tag may be provided on a sticker or label that is applied to an outside surface of the item. The antenna coil of the tag can be printed on, or otherwise formed to be part of or provided by the sticker or label applied to the item. In order to maximise the area within the coil to increase the coupling between the antennas (as described elsewhere herein), the tag antenna coil may be provided around an edge or close to the edge of the label, i.e. to be as big as possible.

[0054] The respective antenna portions 112 are arranged along the receiving zone 114, thereby extending a reading range of the RFID reader antenna 100 within the receiving zone 114.

[0055] Each antenna portion 112 comprises one or more curved parts 120 to form a ring shape 122 around the receiving zone 114 so that each antenna portion operates like an individual antenna coil when the RFID reader antenna 100 is activated.

[0056] As can be seen from Figure 1, the various parts, portions, sections, etc., of the reader antenna 100 are conductively connected. The reader antenna 100 may, for example, be formed from a single antenna coil, conductor, wire, etc., shaped to form the array 102 comprising a plurality of antenna regions 110.

[0057] The receiving zone 114 has a first end 130 and a second end 132, wherein the first end 130 is a receiving end 131 for receiving the tagged item 116, and the antenna region 110 surrounds a length 134 of the receiving zone 114 extending between the first end 130 and the second end 132.

[0058] The plurality of antenna portions 112 of an antenna region 110, in other words, the coil portions or individual antenna coil rings that form a particular antenna region 110, may be positioned adjacent and close together to one another, abut one another, or may be spaced apart longitudinally around the receiving zone. The spacing between adjacent antenna portions may be based on one or more of the diameter of the receiving zone, the diameter of the ring formed by the antenna portions 112, thediameter of the item, the dimensions of the tag antenna coil, and / or the applied power or field strength.

[0059] The RFID reader antenna 100 may have two or more antenna zone arrays 140. Each antenna zone array defines an antenna coil layer around a perimeter of the array of antenna regions 110 that comprises two halves 142, 144: one on either side of the array of antenna regions. Each antenna zone array conductively connects to at least one of: a subjacent antenna zone array, and / or a superjacent antenna zone array. In Figure 1, for example, an upper antenna zone array is connected to a lower antenna zone array via a conductive connection 146. This example shows two antenna zone arrays 140, and therefore two antenna coil layers 150. The RFID reader antenna 100 may have more than two layers, with each additional layer further extending the reading range along an axis for each antenna region 110 and its respective receiving zone 114.

[0060] When the RFID reader antenna 100 is activated, an RFID tag antenna coil 119 within a receiving zone 114 is then able to couple with the resulting magnetic flux. Specifically, because of the relative orientation of the tag coil and the antenna portions 112 that form the individual antenna coils around the receiving zones 114, the RFID tag antenna coils 119 will couple best with a fringing flux produced by these individual antenna coils, as explained hereafter.

[0061] Figure 2 of the drawings shows a side view of an item 116 positioned in a container that has a floor 202. In this example, an RFID antenna coil arrangement is incorporated in a printed circuit board (PCB) 204 that is placed on the floor 202, or incorporated into the floor in a comparable manner, for example positioned inside or below the floor of the container, or otherwise associated with the floor so that the antenna coils of the antenna arrangement are oriented to lie in the plane of the floor of the container.

[0062] The antenna coil has one or more conductor turns. The antenna coil 213 illustrated in Figure 2 has concentric conductor turns 212, and the resulting magnetic field 220 is illustrated with the curved and spreading magnetic field lines 222. Furtheraway from the coil 213 the magnetic field becomes weaker. Also, further away from the coil 213 the magnetic field has a different orientation as the field lines spread out. This can be understood when comparing the more horizontal angle of arrow 226 associated with the magnetic field line close to the coil 213 with the more vertical angle of arrow 228 associated with the magnetic field line furthest from the coil 213.

[0063] Magnetic flux is a measure of the total magnetic field that passes through a given area. As can be seen in Figure 3 of the drawings, the item 116 has an RFID tag 118 with a tag antenna coil 119. In this example, the tag antenna coil 119 has two coil turns 404 and an inner area 402. Referring again to Figure 2 of the drawings, the magnetic flux that results from the magnetic field that passes through the tag antenna coil’s inner area 402, induces an electromotive force, EMF (or voltage) as defined by the rate of change of the magnetic flux. The more magnetic flux generated by the coil 213 that passes through the inner area 402 of the tag antenna coil 119, the stronger the coupling will be between the reader antenna coil 213 and the tag antenna coil 119. The magnetic field lines that spread out further away from the coil, result in a similarly spreading magnetic flux which is referred to herein as “fringing flux”.

[0064] If the reader coil and tag coil lie in parallel planes, a strong magnetic coupling is possible because of the optimal relative orientation of the two coils. However, for some applications, for example for tagged medical items or other items that have an upright orientation, where the RFID tag 118 is required to be applied to the side of the item 116, the tag coil 119 may be positioned to be in a plane perpendicular to the plane that the antenna coil is in if the coil is incorporated in the floor of a shelf, container, holder, or the like (as illustrated in Figure 2, for example). The result is that a horizontal reader coil is used to read a vertically positioned tag coil. This scenario may be accommodated for by using an array of reader coils, for example with the coils positioned to be aligned with predefined locations that correspond to the locations where tagged items will be positioned. In this way, the RFID tag antenna coils couple with a fringing flux produced by the reader antenna coil as illustrated in Figure 2.

[0065] For cylindrical items such as bottles or test tubes, the orientation of the tag on the item may not be controllable because the item can be turned around its axis and hence the reading of the tag should be orientation-insensitive in a radial direction. If the tagged item is rotated, the magnetic field 220 needs to be directed in such a way that the magnetic flux passes through the inner area 402 of the tag antenna coil 119 irrespective of the orientation. Therefore, in a first orientation the magnetic field 220 would need to be in a first direction for coupling to occur, and in a second orientation the magnetic field 220 would need to be in a second direction (perpendicular to the first direction) for coupling to occur.

[0066] The reading field needs to be arranged to cope with any orientation of the item. This is typically done using a 3D field generated by a complex and expensive antenna arrangement. The RFID system described herein provides a simpler solution that takes advantage of the fixed location of the items and the radial symmetry of the rotation of each item around its central axis.

[0067] As illustrated in the example of Figure 4, where a reader antenna coil 213 similar in size to the item 116 is positioned underneath and centred on the item centre, the coil 213 is aligned with the fixed location of the respective tagged item 116. Figure 5 illustrates the field lines emerging from the coil in perspective and in cross-section. As shown in Figure 6, when the tagged item 116 is placed on the coil, a significant portion of the reading field passes through the coil.

[0068] When viewed from above, as illustrated in Figure 7, the radial symmetry of the reading field and the independence from any effects of item rotation are evident. No matter how the tagged item is rotated, the same amount of field couples to the coil.

[0069] The maximum coupling occurs when the reader’s antenna coil 213 is sized and positioned so that the coil 213 lies along the circumference of the item as shown in Figure 8. In this illustrated example, the label is wrapped around half of the item so that the tag antenna coil 119 extends around half of the item and is aligned with half of the reader’s antenna coil 213. Accordingly, about half of the reading field 220 passesthrough the tag 118 (and this is the maximum coupling achievable consistent with the tag 118 also being used for NFC reading where the tag must be readable by a field that travels from one side of the bottle through the bottle to the other side). If the antenna coil 119 extends more than half way around the item the coupling from the straight through NFC field is diminished.

[0070] In the example illustrated in Figure 9, the reading coil 213 has a circumference that is similar to the circumference of the item 116. In this example, the item 116 is placed above the coil 213. The circumference of the coil 213 is aligned with the circumference of the tagged item 116 so that a portion 1702 of the tag antenna coil and a portion 1704 of the reader antenna coil are aligned. The portion 1702 of the tag antenna coil and the portion 1704 of the reader antenna coil may be parallel to one another.

[0071] The reader coil 213 has N turns. The coil acquires an EMF (or voltage) as defined by the rate of change of the magnetic flux. For the type of tightly wound coil used here, the voltage is proportional to the number of turns, N, of the coil:

[0072] Therefore, the more turns N in the coil, the larger the voltage produced by the coil when interrogated by an RFID reader.

[0073] Referring to Figure 10 of the drawings, each reader coil 213 has N turns, and is connected in series with other coils with one or two pairs of connecting coil conductors 1802. In some embodiments the N turns are concentric, which means that each individual turn has a different radius. In other embodiments, to ensure that the radius of the N turns is similar to the radius of the tag coil positioned around the circumference of the item, the N turns of the reader coil have the same radius or have similar radii.

[0074] In such embodiments, the turns are not concentric, and instead are configured to be stacked or layered. This may be achieved through a helical coil configuration.Alternatively, this may be achieved by multiple layers as illustrated in and described with reference to Figure 1 of the drawings.

[0075] As illustrated in Figure 11, the coils 213 can be series connected to create an array 1900 of reading coils. The inductance of one or more coils can be cancelled by a series-connected capacitor or capacitors (not shown). As illustrated in Figure 12, the array can be extended by series connection of a plurality of reader coils 213. Each coil 213 may have one or more turns, and adjacent coils are connected together via a series connection 2004.

[0076] In one example, an array of antenna coils comprises an input conductor forming a first series of coil elements and an output conductor forming a second series of coil elements. The first series of coil elements and the second series of coil elements are conductively connected, for example the input and output conductor may be the same conductor, or may be connected via a conducting component such as a wire, soldering, one or more capacitors and / or resistors, etc. The first series of coil elements is superjacent or subjacent the second series of coil elements so that each antenna coil 213 comprises a first coil element superjacent (or subjacent) a second coil element. Both coil elements that form the antenna coil comprise turns in an opposite direction, for example, the first element may be wound clockwise while the second element may be wound anti -clockwise. This is so that the direction of current (ingoing in the first element and outgoing in the second element, for example) is the same, thereby resulting in similar magnetic fields that sum together to enhance the magnitude of the magnetic field produced by the antenna coil.

[0077] Referring to Figure 13 of the drawings, an RFID system 300 for tracking tagged items comprises an RFID reader 302 and an RFID antenna arrangement 100. The RFID antenna arrangement 100 comprises an array of antenna regions 110, each antenna region 110 defined by a plurality of coaxially arranged antenna coils 304 (which, in some embodiments, may be equi diametrical), each antenna coil 304 comprising one or more curved parts 306 to form a ring shape 308 around a respective antenna region 110.

[0078] In some embodiments the antenna coils may not be equidiametrical, for example where the container, holder, tagged item, and / or receiving zone does not have a cylindrical shape but some other shape (for example frustoconical, so that the antenna coils (and antenna portions) have increasing or decreasing diameters to match the frustoconical shape).

[0079] The RFID reader is configured to create an extended magnetic flux by activating the antenna arrangement to generate, by the plurality of coaxially arranged equidiametrical antenna coils 304, a cascading magnetic flux fringe. The word “cascading” refers to the repeated and overlapping magnet flux fringes created by the multiple layers of antenna coils.

[0080] Each item has an RFID tag with a tag antenna coil, and the cascading magnetic flux fringe is couplable with a tag antenna coil of a tagged item positioned relative to or moving along an axis 310 of a respective antenna region 110. For example, an item may be placed inside a container so that the tag on the item is positioned relative to a lowermost coil so that the tag antenna coil couples with that lowermost coil. If the item is removed, while the item moves out of the container and outward along its respective antenna region, the changing position of the tag antenna coil will cause the initial coupling to be lost.

[0081] As the tag antenna coil moves into and through a subsequent, adjacent magnetic flux (caused by the next layer of antenna coils), the tag antenna coil can then couple with the magnetic flux fringe generated by that next layer of antenna coils, and so forth. Similarly, if the tags are positioned differently on items (e.g., place lower down on one, and placed higher up on another), then the various tags on the various items will still all be couplable to the magnetic field generated by the antenna arrangement, because the coupling can occur with a magnetic flux fringe of any one of the layered coils depending on the position of the tag on the item with respect to the layers of coils.

[0082] Each antenna region 110 may comprise a plurality of antenna portions 112 around a receiving zone 114 for receiving a tagged item. The plurality of coaxially arranged equidiametrical antenna coils 304 may comprise antenna portions 112 arranged along each antenna region 110. Each equidiametrical antenna coil 304 may comprise one or more discontinuous curved parts 306 to form a ring shape 308 around the respective antenna region 110.

[0083] The antenna coil layers 320 each comprise an array 321 of connected coils 304. In this embodiment, two antenna coil layers 320 are illustrated, and each array 321 includes three coils 304.

[0084] Figure 14 is an example of a holder 500 for items, the holder having an RFID reader antenna incorporated therein. In this example, the holder is a holder for test tubes 502 that can have RFID tags applied on them (e.g. via sticker labels) so that each test tube can be tracked and / or identified by an RFID reader when the holder 500 is connected to the reader via the electrical connector 504.

[0085] The inventors have found that, for this type of holder, having the reader antenna coil underneath or below the items held in the holder (i.e., incorporated in the base of the holder), is not optimal. Because the test tubes are longitudinal and of varying lengths, the tags may be positioned too high up on the side of a test tube for the reader antenna to be able to couple efficiently with the tag antenna.

[0086] However, the inventors have found that providing the reader antenna arrangement within, about, and / or as part of the holder in such a way that reader antenna coils are positioned about the test tube receiving slots 506 (provided by apertures in the holder) results in a more efficient and practical antenna design. This is illustrated in Figure 15, where an antenna arrangement 1500 is configured so that the tagged item 1516 can be received within a receiving zone 1514 formed by antenna portions 1512 that, in combination, form a loop or substantially circular-shaped coil around the receiving zone.

[0087] One example embodiment for this type of holder is a PJM Sample Tube Tracker Reader (PSTTR) designed for sample tubes with a diameter and length of 12mm and 75mm respectively. The length of the sample tubes used varies between 10cm and 12.5cm. This means that the PJM label location on a longer sample tube may be further away from the reader circular coil antenna array rendering the tags unreadable. In this example, the PJM label has dimensions 50mm (L) x 32mm (W).

[0088] In the example of the sample tubes used in pathology labs the lengths of the tubes vary, and therefore the placement of the labels in relation to the circular coil antenna array varies as well. The PJM RFID label that is further away will collect less field. One possible way to mitigate this issue is a dedicated PSTTR for use with a specific sample tube length whereby the circular antenna array position is offset in reference to the position of the PJM RFID label. Figure 16 shows the antenna arrangement 1500 of Figure 15 positioned below a tag antenna coil 1619 on the received item 1616, and in this orientation (as explained with reference to Figures 2 and 6, for example), the resulting coupling between the reader antenna and the tag antenna is optimal.

[0089] The downside in this approach is that the user must put the right sample tubes in the right type of PSTTR. This is because wrong label position referencing to the circular antenna array may render the PJM RFID label unreadable.

[0090] Figure 17 shows the antenna arrangement 1500 of Figure 15 coupling with a tag antenna 1719 on a tagged item 1716. If the tag 1718 is positioned on the item in such a way that the relative position between the reader antenna coil and the tag antenna coil have a weak coupling, as illustrated in this figure, then the information on the RFID tag 1718 may not be read accurately. The worst position is when the circular antenna array is placed in the middle of the label as shown in Figure 17. The flux lines above the circular antenna pass through the label in the opposite direction to the flux lines below it. The net sum vector of all flux lines through the PJM RFID label coil is zero. The label will not be energised.

[0091] The inventors have found a unique solution to this problem. The reading range can be extended by providing multiple antenna coils in vertical layers (in the form of a row or a stack of coils) as described with reference to Figures 1 and 13.

[0092] In some embodiments there may be only one container section and only one receiving zone, so that the antenna coil is helical.

[0093] In embodiments where the holder or container accommodates more than one tagged item and / or has more than one container section, the antenna arrangement 1800 may comprise an array 1810 of helical antenna coils 1813, each defining a receiving zone 1814 for receiving a tagged item, as illustrated in Figure 18.

[0094] In embodiments where the holder or container accommodates more than one tagged item and / or has more than one container section, the antenna coil layers 320 may each comprise an array 321 of connected coils 304 as described with reference to Figures 1 and 13.

[0095] Antenna coil layers, for example in the form of a helix or some other form or layering such as those described herein, extend the magnetic flux in the direction of the layers, thereby enabling the magnetic flux to flow further up / down / away before returning through the outside of the loop as can be understood with reference to Figures 19A and 19B. Figures 19A and 19B show an antenna arrangement 1900 that extends the reading range via an array 1921 of layered antenna coils 1904. The extended reading range results in magnetic flux that couples with a tag 1918a placed low on an item (as shown in Figure 19A), and that is also able to couple with a tag 1918b placed high on a tagged item 1916 (as shown in Figure 19B).

[0096] The RFID reader antenna is configured to form an array of antenna regions, each comprising a plurality of antenna portions around a receiving zone for receiving a tagged item. Because the respective antenna portions are arranged along the receiving zone, the reading range of the RFID reader antenna is extended within the receiving zone.

[0097] Advantageously, this eliminates the dependence of the reader accuracy on the label position relative to the reader antenna array position.

[0098] Figure 20A shows an embodiment of an antenna coil layer 2150 forming an antenna zone array 2140 implemented using a printed circuit board (PCB) 2000.

[0099] Figure 20B shows an embodiment of an RFID reader antenna 2100 with four stacked antenna zone arrays 2140. Each antenna zone array defines an antenna coil layer around a perimeter of an array 2002 of antenna regions 2110, and comprises two halves 2142, 2144: one on either side of the array of antenna regions (visible in Figure 20 A). Each antenna zone array conductively connects to at least one of: a subjacent antenna zone array, and / or a supeijacent antenna zone array. In Figure 20B, for example, each antenna zone array 2140 includes at least one electrical connector 2146 for connecting to another antenna zone array above and / or below. This example has four antenna zone arrays 2140, and therefore four antenna coil layers 2150. The RFID reader antenna 2100 may have more (or less) than four layers, with each additional layer further extending the reading range along an axis for each antenna region 2110 and its respective receiving zone 2114.

[0100] Figure 20C shows an embodiment of an RFID reader 2200 electrically connected to the RFID reader antenna 2100 of Figure 20B.

[0101] It is noted that the foregoing has outlined some of the more pertinent nonlimiting embodiments. It will be clear to those skilled in the art that modifications to the disclosed non-limiting embodiment(s) can be effected without departing from the spirit and scope thereof. As such, the described non-limiting embodiment(s) ought to be considered to be merely illustrative of some of the more prominent features and applications. Other beneficial results can be realized by applying the non-limiting embodiments in a different manner or modifying them in ways known to those familiar with the art. The mixing and matching of features, elements and / or functions between various non-limiting embodiment(s) is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elementsand / or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise, above. Although the description is made for particular arrangements and methods, the intent and concept thereof may be suitable and applicable to other arrangements and applications.

[0102] In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.

Claims

CLAIMS:

1. An RFID reader antenna configured to form an array of antenna regions,each antenna region comprising a plurality of antenna portions around a receiving zone for receiving a tagged item,wherein the respective antenna portions are arranged along the receiving zone thereby extending a reading range of the RFID reader antenna within the receiving zone.

2. The RFID reader antenna of claim 1 comprising a single antenna coil shaped to form the array comprising a plurality of antenna regions.

3. The RFID reader antenna of claim 1 or claim 2, wherein the receiving zone has a first end and a second end, wherein the first end is a receiving end for receiving the tagged item, and wherein each antenna region surrounds a length of the receiving zone extending between the first end and the second end.

4. The RFID reader antenna of any one of the preceding claims, wherein the tagged item comprises a passive RFID tag with an RFID tag antenna coil at an outer wall or a perimeter of the item.

5. The RFID reader antenna of any one of the preceding claims, wherein each antenna portion comprises one or more curved parts to form a ring shape around the receiving zone so that each antenna portion operates like an antenna coil when the RFID reader antenna is activated.

6. The RFID reader antenna of any one of the preceding claims, wherein the plurality of antenna portions of an antenna region are spaced apart longitudinally around the receiving zone.

7. The RFID reader antenna of any one of the preceding claims, comprising two or more antenna zone arrays, each antenna zone array:defining an antenna coil layer around a perimeter of the array of antenna regions;comprising two halves, one on either side of the array of antenna regions; andconductively connecting to at least one of a subjacent antenna zone array, and a supeijacent antenna zone array.

8. An RFID system for tracking tagged items, each item having an RFID tag with a tag antenna coil, the system comprising:an RFID reader; andan RFID antenna arrangement comprising:an array of antenna regions, each antenna region defined by a plurality of coaxially arranged equidiametrical antenna coils, each antenna coil comprising one or more curved parts to form a ring shape around a respective antenna region,wherein the RFID reader is configured to create an extended magnetic flux by activating the antenna arrangement to generate, by the plurality of coaxially arranged equidiametrical antenna coils, a cascading magnetic flux fringe that is couplable with a tag antenna coil of a tagged item positioned relative to or moving along an axis of a respective antenna region.

9. The RFID system of claim 8, wherein each antenna region comprises a plurality of antenna portions around a receiving zone for receiving a tagged item.

10. The RFID system of claim 8 or claim 9, wherein the plurality of coaxially arranged equidiametrical antenna coils comprise antenna portions arranged along each antenna region.

11. The RFID system of any one of claims 8 to 10, wherein each equi diametrical antenna coil comprises one or more discontinuous curved parts to form a ring shape around the respective antenna region.

12. An RFID reader antenna configured to extend a reading range of an antenna region, the RFID reader antenna comprising two or more antenna portions around a receiving zone for receiving a tagged item, wherein the respective antenna portions are provided along the receiving zone thereby extending the reading range of the RFID reader antenna within the receiving zone.

13. The RFID reader antenna of claim 12 wherein the two or more antenna portions are layered to form a helical shape.

14. An RFID antenna arrangement comprising two or more RFID reader antennas according to claim 12 or claim 13, wherein the two or more RFID reader antennas are electrically connected to one another to form a series array of RFID reader antennas, each RFID reader antenna associated with a respective receiving zone and a respective reading range.

15. The RFID reader antenna of claim 12, comprising an array of antenna layers that are layered along and about an array of receiving zones to extend a reading range of each receiving zone,wherein each antenna layer comprises a plurality of antenna portions electrically connected to one another within their layer, and wherein the plurality of antenna portions extend about the array of receiving zones.

Images