GB2598380A - UHF GEN 2 RFID tag embodiment works in conjunction with its location on a bottle neck to provide resonant structure - Google Patents

Abstract

An ultra-high frequency (UHF) radio frequency identification (RFID) tag is positioned on the neck of a vessel, such as a wine bottle 1. The effective length of the tag’s antenna is such that resonance is created at UHF RFID transponder frequencies, such as 886MHz in Europe and 915MHz in USA. This can be achieved by the tag overlapping the bottle’s metallic capsule 7, 10 to create a combined length of one quarter of the transponder’s wavelength. Alternatively, the tag’s integral antenna, such as a squiggle antenna 9, can be used to achieve the required length in the absence of a metallic capsule. A spacer which leaves a residue when removed may be provided between the tag and the capsule. The tag may have a paper circle at its top to aid correct positioning on the bottle. The tag may be constructed as a half wave dipole. The tag may be able to detect tampering by a disconnect though the tag matching loop. The tag may include an integrated chip (IC, RFIC) which may contain both UHF and near-field communication (NFC) transponders.

Description

UHF RFID TAG LOCATION ON BOTTLES AND OTHER VESSELS TO

ENHANCE THE READ RANGE

A long range UHF RFID Tag is located on a bottle so that its location and length create a resonant structure, giving rise to longer range UHF RFID reading and programming ranges.

Abbreviations: UHF = Ultra High Frequency. >100MHz; usually 866MHz in Europe and 915MHz in the USA NFC = Near Field Communication. Uses magnetic coupling between coils. 13.56MHz worldwide RF = Radio frequency HF = High frequency, usually 13.56MHz for short range card transactions etc. IC = Intergraded circuit Chip = Same as:Integrated circuit-but without encapsulation.

RFID = Radio Frequency Identification.

Back Scatter = UHF RFID tags have no batteries they rely on the power transmitted by the reader to power up and work. When powered the tag can vary its reflectivity, this can be picked up by the reader or other readers as data. The data can be the same as the barcode on the bottle or have many more parameters associated with this actual singular bottle of wine or spirit. Gen 2 = the standard which all reader and tag manufacturers use so they remain compatible with each other. Tag ranges can vary between a few cm to 12-F meters depending on the application. The Gen 2 standard in Europe is E N302-208.

Background

This invention describes a specific tag length and positioning which relies on the principles of previous granted patents; GB2493996 and GB1400142.4. The original patent GB2493996 describes how the fluid in a bottle can be used to sink current into the fluid within the vessel to create current flow through a UHF tuned loop to gain excellent UHF range using standard UHF RFID equipment (G en 2 standard at this present time).

Note. Usually UHF tags communicate with the reader over large distances (12-i-meters); this type of tag utilises the electrical part of the electromagnetic wave.

NFC tags communicate with a reader, or smart phone, over short distances 5cm typically; this type of tag utilises the magnetic part of the electromagnetic wave. The embodiment described can be used for tags containing a combination of UHF long range and UHF near field; however, this patent is not relevant to 13.56 MHz standard HF tags when no UHF transponder is present History Before GB2493996 was published, fluid in a bottle was known to absorbed the energy from UHF tags and so severely reduced the tags range 10cm commonly. Before this invention it was always said that you cannot use UHF long range RFID tags on bottles. GB2493996 showed how the fluid absorption properties (like a microwave oven) could be used to enhance the range of a UHF tag rather than decrease its range.

Using the above invention, ranges of 12 meters can be achieved whilst staying within 2W maximum E RP (Effective radiated power) specified in E N302-208. This is the current ETS I regulatory standard; however, A new EU band is now available which will increase tag ranges by a bout 25%.

In the USA, 4W EiRP (Effective isotropic radiated power) is the maximum power stated by the USA FCC regulatory body. (4W EiRP is only slightly higher than the European 2W ER P).

Using this invention extends bottle read ranges to 12 or 15 metres, in good conditions this gives time to do an inventory of 100 bottles down to as little as 1 second.

Inventive Step: This patent describes the precise location on a bottle or vessel where the Tag (known as a Ca pTag) can be placed to create a resonant structure; this is achieved by using the capsule and the tags combined length to achieve a quarter lambda resonant length.

The inventive step in this patent is how the tag length and its position can be used to create a resonant quarter lambda antenna so that the resulting structure becomes a tuned monopole and efficiently collect energy and modulation from a standard UHF RFID reader. Further claims show how this embodiment can be improved by optimising various parameters associated with the structure to maximise efficiency and increase the structures range still further.

The embodiment shown in F igure1 is a resonant structure which is created by adding a specially designed UHF R F ID tag to the conductive capsule on wine/spirit bottles. The special tag must be positioned accurately for a long range R FID:back scatter-structure to be created.

Key to Drawing Figure 1 1. Fluid filled bottle; Glass or Plastic.

2. Thin plastic film carrying the printed Aluminium or other conductive material which forms the tag antenna.

3. Under the tag is a glue which holds the tag to the vessel; between the tag and the glue layer a spacer can be used; this can provide tamper evidence and also create a complex conjugate match between the tag and the bottle, to facilitate maximum power transfer.

4. This is the tuned resonant cavity which is used for tuning the tag to the Integrated circuit again to facilitate maximum power transfer.

5. This is a standard Gen 2 R F ID UHF integrated circuit Many types exist 6. This drawing shows a screw cap wine bottle top with a capsule fig1-10, this Patent functions even more efficiently with a standard corked bottle or bottle with a non conductive capsule.

7. This is the top of the capsule and can be thought of as the top of the antenna, this is part of the resonant property of this embodiment covered by this patent 8. These marks show the position of the twist grip; when opened the screw cap splits from the metallic skirt fig1-10 at point figure1-6. With a corked wine the capsule is usually cut at this point 9. This is a squiggle antenna (inductive) which allows this embodiment to still function when a capsule is not present. The squiggles are used to extend the effective length of the antenna; however, when this structure is used with a capsule this part of the embodiment is optional as it becomes non functional when next to the capsule metal.

10. This is the skirt of the capsule and is usually conductive aluminium. If the capsule is non conductive then the squiggle antenna is required to form a resonant monopole antenna.

11. This is the bottom of the metal capsule. The distance from figure1-7 to figure1-11 is usually 50mm or 60mm. This embodiment can be affected by this length to a small extent.

12. This embodiment gives the greatest range when the wine or other fluid is between figure1-11 and figure1-12. If the fluid goes up inside the capsule the embodiment loses efficiency; fortunately the amount of fluid inside the capsule is usually restricted by the stopper means.

13. This is the conductive part of the tag which is usually aluminium; however, any highly conductive material can be used for this area. It forms a capacitive plate which allows RF energy to pass into the fluid through the glass or plastic.

14. This is the bottom of the tag structure; its position relative to fig1-7 is fundamental to this patent

Detailed Description of the embodiment Figure 1.

As described in previous patent the capsule on a bottle can be used to collect RF energy from a reader and also the fluid can be used to form a path to ground which then creates current flow through the tag; this greatly improves the range of the tag.

This patent extends the range of the CapTag (bottle tag) by adding length to the capsule so that the tag and the capsule combine to become a quarter wavelengths between the top of the bottle to the bottom of the R F ID tag. A quarter wavelength of metal resonates at a particular frequency which can be calculated very easily.

L = C/(4xF) formula for quarter wave resonance.

L = the length of the conductive structure, C = the speed of light 3e8 m/s, F = the frequency, usually 866MHz EU or 916MHz USA. 950MHz is the highest known frequency used for Gen 2 UHF RFID.

Unfortunately, even the longest capsule will not resonate at these frequencies; A 6cm capsule will resonate at a frequency much too high for UHF RFID readers.

We can calculate the resonant frequency of a 6cm capsule as follows: Re arranging the above formula we get F = C/(Lx4) C = the speed of light 2.98e8 which is 298,000,000 meters per second. L = 0.06 meters = 6cm So the capsule on it own will resonate at 1.24 GHz which is far too high; we need the structure to resonate at 866MHz EU or 915MHz USA etc. If we calculate the required length for say 866MHz EU, we need a resonant length (capsule length) of: L=C/(4xF) Which is.086 meters = 8.6cm.

The inventive step in this patent is how to extend the length of the capsule using the bottle tag tail fig1-13 so a resonance occurs at the desired frequency. This inventive step applies to capsules on bottle and other similar glass or plastic vessels.

Even though the tag has no metal to metal contact with the capsule, an excellent RF capacitance connection is established using the large areas of metal shown in fig1-13. This capacitance forms a low impedance path at these ultra-high frequencies.

To achieve the desired resonance, we need to place the tag in a position so that the distance between figure1-7 and figure1-14 is equal to 8.6cm. For the USA the target frequency 916MHz and so, for this region, the tag should be placed so the distance between figure1-7 and figure1-14 is 8.13cm.

Resonant structures like this have a:Q-factor (Quality factor) which is expressed as the tuned frequency divided by the difference between the two -3dB frequencies. This has been measured and found to be wide enough to accommodate worldwide Gen 2 UHF RFID frequencies (the Q factor is approximately 3) The reason for this low Q factor is that lengthening the capsule in one location doesnt completely remove the higher frequency resonant from the 6cm capsule itself. So the resulting wide Q factor is a result of two tuned lengths 8.6cm and 6cm, this low Q factor is actually a benefit to this embodiment.

Graph 1 below shows the typical frequency responses of the embodiment in drawing Figure 1.

Graph 1, shows the 6.0cm capsule resonance in combination with the 8.6cm resonance of the total length of the structure, this is an example embodiment of this invention.

The 866 MHz resonance and the approximate 1.1GHz resonant frequencies can be seen to combine. This test was performed on a full wine bottle as shown in Figure 1-12. The resulting wide:Q -factor creates a structure which will give exceptional range in all UHF RFID regions around the world.

Explanation of other claims.

The loop structure seen on almost all UHF RFID tags acts as a transformer to transforms impedances between the antenna and the integrated circuit this creates maximum power transfer between the antenna and the IC. This is known as complex congregate matching.

Spacer The power match between the tag and the capsule can be further enhanced by the use of a:spacer-between the tag and the capsule; or, between the whole tag and the bottle. Thin spacers can improve the impedance match and at the same time provide tamper evidence.

S

Materials have been found which not only provide the spacing required for maximum power transfer; some material have been designed to leave a tamper evident residue if the tag is removed from the bottle. (Usually the reason for removal is theft) Matching transformer In the embodiment shown in Figure 1 the matching loop containing the chip has been elongated. A normal shaped rounded loop would have two main disadvantages; first it would be severely affected by slightly different location on the capsule; covering all or part or the loop. Secondly it would be too wide to fit onto a lOmm wide tax strip, which is a prime market for this range of security tags. Elongating the loop is a sub claim as it only aides the tuning of the loop, when accurately positioned, a round transformer loop is equally as effective.

Tuning The tag must also be pre tuned to a higher frequency so that it moves down to the correct frequency for UHF R FID when placed on a bottle.

Positioning: To accurately position the tag on a bottle one of the claims describes a paper circle at the top of the tag. When this circle is placed on the top of the bottle and the tag folded down the side of the bottle the tag length and chip position are accurately aligned with the capsule for best performance. This method usually results in a positional accuracy of +-1mm.

The invented tag structure will have double the range when the tag is at the back of the bottle and read from the front! This is completely counter intuitive as you would certainly expect the tag to be used on the same side of the bottle as the reading antenna.

The reason for this anomaly is that the tag is not a conventional dipole like other RFID tags. In this embodiment it becomes a grounded monopole antenna. The fluid acts as the ground to the monopole and when the tag is at the back of the bottle the absorption of signal from the front into the fluid is increased providing a better signal ground for the antenna. The gain of the monopole antenna is in the order of 4dB.

These tags can be further optimised for different capsule lengths by moving the position of the resonant loop either up or down the tag. This allows for more accurate tuning of the loop. Note, by moving the tag up or down, the quarter wavelength accuracy is compromised; however, as the antenna length efficiency is a Cosine function, absolute length accuracy is not required.

Luckily most capsules fall into two sizes either 5.5cm or 6cm so tags can be designed primarily for these two capsule lengths.

The squiggle antenna fig1-9 also has to be positioned so that the tag structure is resonant The distance between fig1-14 and Fig1-6 is crucial for tuning. The squiggle antenna shortens the effective length so that the whole tag is now the tuned length.

Bottles without capsules.

The antenna allows the tag to be used on almost all upright bottles in any RFID region. Bottles on their sides with no stopper still give some usable range; however, this is reduced to just one or two meters. Bottles kept horizontally usually have a stopper means, this assists range by blocking the fluid from fully entering the capsule. (This is a general problem and has been overcome in an earlier patent by creating an insulating gap at the base of the stopper means.) A standard tag used on the bottleneck.

Most UHF R FID tags are constructed using a dipole antenna; however, they can act as a monopole when attached over the capsule and fluid on the neck of a bottle. As one antenna of the tag is over the fluid it acts as a capacitor coupling the signal into the fluid rather than an antenna. Therefore, the use of a dipole tag with one of the antennas over the fluid results in the same embodiment as described in this patent and so would be considered as an infringement [AS All tests have shown better performance and flexibility in comparison to today EAS anti theft systems. Along with the above the tags are low cost and can be left on the bottle for traceability or customer reward schemes. Also, the data on the tag can be erased or the tag killed at the payment point or shop exits. Some UHF Gen 2 tags now carry an E AS protocol.

UHF and HF(NFC) The effective resonant length of the UHF tag can also be extended using an integral NFC 13.56 MHz tag to the bottom of the UHF tag. Either using a dual frequency chip or two separate chips, as long as a direct contact or a close metal overlap is provided between the UHF tag and the NFC low frequency tag, then the NFC tag can be used to extend the length of the capsule to one quarter wavelength and so extend the range of the UHF transceiver. This also allows interaction at close range with smart phones. This inventive step is cover in a previous granted patent and so not part of any claim in this patent General Information: Why tag bottles? Unfortunately, a very high percentage of wines and spirits moving through the supply chain today are known to be fake! Import duty can be avoided by re-filling used bottles with substandard wines or spirits. Faking wine bottles and spirits for black market sales to avoid import taxes or direct profit is more common than you would expect Counterfeit spirit or wines do not only cause significant losses of earnings for the true manufacturer and custom/excise authorities, they also put the public -s health at risk. Some of the brewing and distilling methods used to create the fake wines and spirit have dangerous toxins which can pose serious health problems, like blindness and in some cases death.

Sadly, theft between the store room and the sales shelves is as much of a concern to some shops as theft by customers. Doorway monitoring, and better still, constant real-time automated stock inventory systems can now be implemented to reduce theft. Some systems use covert tags to identify theft by monitoring the bottle movements and registering this with video footage to identify the thief. Sometimes it is better to discourage theft by the use an overt tag to reduce opportunistic theft.

It has been found recently that most of the missing wine bottles were never actually stolen in the first place as they never arrived at the recipient If a company's goods inward checks are substandard, when shortages occur they are frequently assumed to be staff theft rather than shortfalls in the delivery.

Capsule Tags allow accurate inventory of bottles received even without opening the boxes! The capsule tag can be read and logged through the cardboard or wood shipping boxes. It is surprising how theft miraculously reduces when some suppliers are forced to tag product before shipping.

Bottles can now be verified at long range using low cost readers attached to iP hone or Android phones etc. Read ranges are very good when antennas are pointed down at 45 degrees to boxes of upright bottles.

One major advantage of using the tag positioned as shown in this patent is that tags cannot come in contact with each other (shadowing) or come close to the fluid in other bottles, (RF absorption). This dramatically improves the consistency of reads, especially with large numbers of bodes in close proximity.

Overt tagging can also be implemented to discourage theft by printing:radio tagged-or something similar, on the strap or tax strip covering the bottle top. This can be demonstrated to customers and also used as a sales tool to show details of the wine or spirit selected on the closest monitor, mirror or dedicated screen.

Using R F ID to tag bottles is an obvious step forward; however, the costs involved have been two prohibitive until the advent of patented method GB2493996 which adds as little as 6 US cent to the cost of the spirit or fine wine.

New chips are being developed all the time with I/O outputs and I2C two wire communication bus to a plethora of transducers; the principles in this patent can work alongside these transducers to form low cost effective monitoring, customer engagement and inventory systems.

David Mapleston 01/07/2020

Claims (14)

1. CLAIMS1. A UHF RFID tag is positioned in a specific location on the neck of a vessel such as a wine bottle to increase the effective length of the covering conductive capsule such that the resulting structure is resonant at UHF RFID transponder frequencies. The resulting resonant structure gathers increased radio energy from the interigating readers signal to gain increased transponder range.
2. 2. A tag as described in Claim 1 and illustrated in Figure 1 where the tag can still operate without the capsule due to an integral antenna of any type.
3. 3. A tag as described in Claim 1 and illustrated in Figure 1 where the tag uses a spacer between the tag and the capsule to improve the matching and hence improve the maximum power transfer between the capsule and the tag.
4. 4. A tag as described in Claim 1 and illustrated in Figure 1 where the tag spacer leaves a residue when the tag is removed from the vessel to indicate tamper.
5. 5. A tag as described in Claim 1 and illustrated in Figure 1 where the resonant loop feeding the integrated circuit is elongated and narrowed to reduce the de-tuning effect of different tag locations.
6. 6. A tag as described in Claim 1 and illustrated in Figure 1 where the resonant loop feeding the integrated circuit is elongated and narrowed so that it can fit on a standard width bottle tax strip.
7. 7. A tag embodiment as in Claim 1 and the description where the converted tag has a paper circle at the top of the tag to aid easy application and facilitate the correct position on the capsule so it extends the capsule length for resonance.
8. 8. An embodiment as in Claim 1 where the tag is constructed as a half wave dipole.
9. 9. A tag embodiment as in the description and Claim 1 where the integrated circuit power requirement is assisted by a power source of any type.
10. 10.A tag embodiment as in any prior claim where tamper evident means is provided by a disconnect through the tag matching loop.
11. 11.A tag as described in Claim 1 where a dedicated loop is made closed or opened by a tamper attempt.
12. 12.A tag invention as in claim 1 which has the capability of changing its code when a tamper attempt on the UHF tag is made by any means.
13. 13.A tag invention as in claim 1 which has the capability of changing its code when a tamper attempt on the NFC tag is made by any means.
14. 14.An embodiment where the tag is a single chip containing both UHF and HF NFC transponders.