GB2493996A - RFID tag interacting with metal seal of bottle producing electric field - Google Patents

Abstract

A near field loop RFID tag 4, 9 interacts with the metal foil cover 1 or metal lid of a bottle 2 so that the tag can communicate via a high range electric field. Ideally the metal seal and the tag have matching impedance. Preferably fluid contained in the bottle 2 absorbs radio waves creating current flow in the loop 7. The tag can be printed with a capsule 1, 5, printed on a label 3, or integrally formed with the lid or foil 5.

Description

Long Range UHF RFID Tag for bottles

Background

Many wines and spirits moving through the supply chain and retail industry are now known to be fake. These counterfeit bottles do not only cause significant losses of earnings for the true manufacturer, they also put the public's health at risk. Some of the brewing and distilling methods used to create the fake wines and spirits create dangerous toxins which can pose a serious health risk.

Using AFID to tag bottles is an obvious step forward; however, the costs involved with all current tags and tagging methods have precluded manufacturers from tagging all but the most expensive wines and spirits.

Although some UHF RFID tags are now down to a traction of a dollar, their range is reduced from meters to just 10cm by the absorption of the RF signal by the fluid in the bottle.

Lower frequency tags at 13.56MHz and below do work on fluids; however, they are costly and cannot be covertly integrated within the aesthetics of the bottle, capsule or label.

This patent describes an attachment method for a low cost near field tag. The tag is changed into a long range far field tag using the metal capsule cover frequently used on wines and spirit bottles.

This metal capsule converts the tag into a long range tag that can be covertly, aesthetically and cost effectively used on bottles and other containers.

An e-Pedigree can be given to each specific bottle; not only authenticity but traceability can be given to each individual bottle.

This type of tagging can also control the production of gray/black market produce as bottles without tags will be obviously identified as fake.

Wines can be dated precisely and also a good deal of other information can be stored in the tag.

Tags can also be used by restaurants to find, identify and to re-order the product automatically.

Other attempts to solve the bottle tagging problem use RF tuned cavities to create decoupling between the tag and the fluid. Omni-ID has such a solution. This method is both too costly and at 1mm thick it cannot be covertly placed on the bottle.

Description of embodiment:

Note, the word bottle used in this description covers glass and plastic containers and other non conductive fluid containing vessels that can be fitted with a capsule or that already have a lid of sufficient physical size to capture the necessary amount of radiated electrical E field energy.

Note,' near field' refers to the H or magnetic part of the radiated electromagnetic field.

In general tags have not been used in the bottling industry due mainly to cost and physical size.

The capsule tag design described in this patent uses a tag that is paper thin measuring typically 19mm X 12.5mm, with the cost down to les than 9c in moderate volumes. The protctype first embodiment tag could be read consistently at over two meters using a conventional full bottle of champagne and radiated energy well within the EN302 208 regulations.

The chip within the tag embodiment can be any of a number of RFID near field tags. The initial tests were performed using a Gen 2 Alien technology Higgs 3 eFC compliant integrated circuit.

This patent describes how a near field tag structure such as the Alien SIT near field tag, Shown in figure 1-4 and figure 2-9, can be attached to a conventional bottle capsule (Fig 2-5) to form a long

range electric field tag.

The near field tag figure 2 -9 is a simple loop of printed, sputtered or etched metal (fig2-7,) connected to an eFC compliant RFID chip Fig2 -8.

This loop has been manufactured for near field use; the loop forms a coil which can pick up the power and data from a 900MHz oscillating magnetic field. It has no antenna and so ts ability to pick up an electric fields at long rang is very limited. This loop structure has a very low range because the magnetic field reduces with distance as a function of the cube of the distance! As the tag must reflect energy back to the reader this range reduction falls at twice this rate. Ranges of just two to five cm can normally be achieved using this simple H magnetic field structure.

The present embodiment of this invention is shown is figurel and is described using a champagne bottle as an example. This invention has been tested on a plurality of bottles containing wines, spirits and beers and using a range of different sizes and shapes of capsule; all gave adequate long range performance using this invention.

The capsule Figure 1-1 is a simple aluminum or other metallic covering over the bottle lid or cork Figure 1 show the placement of the tag (ligurel -4) on a capsule (figure 2-5). The tag must be placed so that the loop (figure 2-7) partially covers the capsule and partly covers the glass of the bottle, as shown in figure 2. No actual electrical DC contact is required as the RF coupling through stray capacitance is sufficient to provide a good reading range; however, Improvements may be made by printing the tag loop as part of the capsule.

The tag can be placed on the capsule before manufacture or on the bottle after manufacture. The tag is so small and thin that it can be covertly placed under the manufacturers Logo/seal or used as a promotional sticker as shown in figure 1-4.

The tag contains a fixed code and a variable pre programmed changeable 96bit code number.

The tag also has a 500bit programmable used data area and a burned in unchangeable UTD identification code.

As the tag is pre programmed there is very little to be gained by writing to the tag unless information needs to be updated; for example on refilling the container etc. Theory of operation of the capsule tag.

The theory of operation is quite complex and mathematical; however, here is a practical description of the method used to acquire adequate range from the Alien SIT near field tag, any other H field UHF tag should perform similarly; however, the Alien Higgs chip exhibits a high level of back scatter modulation depth which aids this invention.

The Alien SIT tag is basically a tuned loop, this SIT tag is designed to respond to close range

magnetic field.

As mentioned the magnetic field is very strong close to the read antenna but dies away at a cube of the distance, conversely the electric field dies away at just the square of the distance from the antenna and so longer ranges can be achieved at low RF power using the electric field.

Applying these tags to a capsule and to a bottle to archive significantly more range has been achieved by using the capsule to turn the H field lag into an electric field tag.

The electric field from a standard RFID antenna is captured by the capsule foil, the near field tag is placed as shown in figure 2 so that a proportion of the tag is capacitive (or DC) coupled to the foil and the other, opposite part of tag loop, is capacitive coupled to the fluid in the bottle.

The above construction has some of the loop connected to the E field on the foil and some of the loop effectively grounded by the absorption of RF by the fluid. This caused high frequency AC current to flow in the loop at a voltage adequate to power up the RFID chip. This is affective; however, not adequate for a range of 2 Meters using just a 2W ERF transmitter. (2E ERP is the legal limit in Europe which is just a few percent below the 4W EIRP allowed in the USA).

Extra range can be achieved by moving the H field loop tag further under the capsule; this effectively reduces the size of the loop and tunes the loop to a higher resonate frequency.

By moving the tag farther under the capsule you are effectively reducing the area (Fgure 2-6) and increasing the resonant frequency of the loop. You are effectively tuning the tag to the desired frequency.

The loop is actually slightly off tune as for maximum range the loop must satisfy two criteria. First it must tune to approximately 900MHz or the UHF RFID frequency were the tag is likely to be interrogated and it must also form a complex congregate match to the RFID chips input impedance so the transfer of energy into the RFID chip is efficiently.

This complex congregate impedance matches from the current and voltage provided by the capsule to the capacitive, resistive and inductive nput impedance of the AFID chip could be maximized using more complex printed structures rather than the simple loop structure shown in this embodiment.

With this simple loop this matching can be adjusted by the location of the tag over the metal capsule; experiments have been performed to find the point of optimum performance where the loop tunes and still provided a good impedance match to the RFID chip.

Experiments have shown that the most effective location in the current embodiment using the Alien SIT tag is when the tag protrudes from under the foil by 12mm. This coincides with approximate calculated values.

The tolerance of 1mm has been chosen as with this error in the location, the tag range is just measurably reduced.

Due to the high RF power used for these application (typically 2W), reflections from other metal/material causes large RF nulls and hence the environment for a practical system will need to be carefully controlled.

Hand held readers can achieve 8 cm range with ease and would be very useful in this industry for identifying wines and spirits in vans trucks or cellars.

This invention therefore provides a cost effective small covert method of RFID tagging bottles and other containers with relatively long range reading ol the tag.

Improved matching circuit shapes, better contact to the capsule and more advanced low power RFID chips will all conspire to achieve much longer ranges with more repeatability in the very near future.

Claims (3)

1. <claim-text>CLAIMS1. A near field loop REID tag implemented as described and illustrated in Figures 1 and 2 functioning to identify a bottle or other fluid containing vessel using the metal foil or lid to change the function of the near field tag into a high range electric field tag.</claim-text> <claim-text>2. A tag embodiment as in the description and claim 1 where the metal foil and the tag are formed as one tag and antenna structure.</claim-text> <claim-text>3. A tag embodiment as in the description and all previous claims where the metal foil and the tag are formed to create a matching impedance transform between the capsule and the REID chip.</claim-text> <claim-text>4. A tag embodiment as in claim 1 where the metal forming the tag loop has a structure which impedance matches the electric field from the capsule directly into the REID chip.</claim-text> <claim-text>5. An embodiment of the tag structure described in all previous claims where the fluid in the bottle is used as an RE absorber to create current flow in a 1oop or coil.</claim-text> <claim-text>6. An embodiment of the tag described in all previous claims where the structure of the tag is printed with the capsule.</claim-text> <claim-text>7. An embodiment of the tag described in all previous claims where the structure of the tag is printed on a bottle label.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS1. A covert long range UHF radio tag on a bottle utilises a near field magnetic coupled REID tag in combination with the metal foil capsule on the bottles which excites current flow in a near field tag ioop to create a higher range electric field tag structure by means of placement of the near field tag loop partly under or over the capsule so that it is excited to resonate by the current flowing between the capsule and the radio absorbent fluid in the bottle; the current in the loop or coil activates a integrated circuit chip in the near field loop; the resulting flat tag. without any form of encapsulation or dielectric separating material between the tag and the bottle, allows the tag structure to be placed covertly under a paper label and directly in contact with the bottle.
2. 2. A tag embodiment as in the description and claim 1 where the metal foil and the tag are formed as a single tag and antenna structure.
3. 3. A tag embodiment as in the description and all previous claims where the metal foil and the tag are formed to create a matching impedance transform between the capsule and the RFID Chip. *4. A tag embodiment as in claim 1 where the metal forming the tag loop has a structure which impedance matches the electric field from the * capsule directly into the RFID chip.5. An embodiment of the tag described in all previous claims where the structure of the tag is printed with the capsule.6. An embodiment of the tag described in all previous claims where the structure of the tag is printed on a bottle label.</claim-text>