GB2542574A

GB2542574A - A UHF RF radio power harvesting method for vessels

Info

Publication number: GB2542574A
Application number: GB1516794.3A
Authority: GB
Inventors: Bernard Mapleston David
Original assignee: Captag Solutions Ltd
Current assignee: CAPTAG SOLUTIONS LTD
Priority date: 2015-09-22
Filing date: 2015-09-22
Publication date: 2017-03-29
Also published as: GB201516794D0

Abstract

A liquid container 5 has an RF collector 1 which receives transmitted power, and a capacitive connection 8 through the container to the liquid 6 such that when placed in an RF field a current is generated to flow through an electrically powered device 7 placed between the RF collector and the capacitive connector. The device may be an RF transponder such as an RFID tag, a display such as an LED, an audio emitter, a temperature sensor, a vibration sensor, or a humidity sensor. The device may signal that a tamper event has occurred, and the arrangement may be such that damage to the circuit disrupts current flow. The container is preferably a bottle, with the RF collector 1 comprising a lid, cap, or metallic foil capsule of the bottle, or an antenna placed on or around the bottle (see figure 1).

Description

This invention describes a method of supplying harvested power to low power circuits on bottles, containers, jars and other non conductive vessels. It relies on the principles of my previous granted patent; GB2493996. This granted patent describes how the fluid in a bottle can be used to sink current and create current flow through an RFID tag to obtain excellent reading range, using standard UHF RFID equipment. The range improvement, using the fluid in the bottle to create a dispersive ground, is from approximately 0.5 meters to 10 meters using a standard Gen2 RFID reader.

This new invention uses the fluid in vessel in the same way as GB2493996, with the inventive step that any low power display or audio circuit, not just a tag, can be powered using the fluid in the bottle to dissipate energy and create useful current flow.

This patent is described as A UHF Energy Harvesting method and allows almost any glass or plastic vessel to collect enough energy to power circuits to create changing displays or sounds when the vessel is located within a suitable RF field. Batteries or super-caps can be used to store the energy collected if required. For example a super-cap could be used if the display or sounder should need continued power to make a sound or change the displayed when the vessel is no longer powered by the radio field; or, if a large burst of current is required by the circuit.

Figure 1 shows a typical embodiment of this invention, where the circuit to be powered is a display device. In this embodiment a simple LED fig1,7 is used to demonstrate the high amount of power harvested by a vessel which is placed in a UHF radio field.

Figure 2 shows another embodiment of the above but this time using an antenna structure to allow the invention to work on bottles which have non metallic capsules or no capsule at all.

The embodiment shown in Figure2 has optional pads strategically placed along the antenna; these allow this embodiment to work on bottles with or without a metal capsule. When the antenna embodiment Figure2 is placed over a metal capsule the pads form a capacitive connection to the capsule which reduces the function of the antenna but increases the RF signal pickup from the capsule.

It should be noted that the capsules don’t need to be tuned to the radio signal as they have a large radar capture area within the UHF band. This principle also applies to jars with metal lids etc.

The LED can be replaced with any type of display device or audio device as this patent is concerned with the method of providing power to such devices using harvested UHF radio energy and not just an LED. UHF stands for Ultra High Frequency which is defined as frequencies between 300MHz and 3GHz. The embodiments described will work outside this frequency band but in general with less efficiency.

Fig1,1 is the metal capsule used on wine, champagne, beer, larger and some spirits bottles. In this invention this capsule collects the radio electromagnetic wave which is used to power the LED shown in Fig1,7

Alternatively bottles with no metallic capsule can use the antenna which can stretch over the top of the bottle, this Embodiment is shown in Figure2 and the antenna shown as Fig2,2. A short antenna tuned to 866MHz gives about the same performance as the capsule. So the two Embodiments Figurel and Figure2 show how energy can be harvested on bottles with or without metallic capsules. Fig2,1 is a glass or plastic bottle with no metallic capsule. Both embodiments work perfectly well if the bottle has a metallic cap. A Functional description of the demonstration Embodiments, shown in Figurel and Figure2 and is described as follows.

The radio energy which is picked up by the capsule or antenna would not create current flow to power a device unless it had a path to ground or to something which absorbs or disperses this current. The use of the fluid in the bottle to absorb and disperse the radio energy, somewhat like a ground connection, is fundamental to this patent. This path to ‘ground’ creates current flow through the LED shown in the embodiments or in the Device to be powered.

First a connection is made between the capsule Fig1,1 and the circuit board Fig1,3 this connection can be a direct DC connection; however, at high frequencies a simple capacitive plate Fig1,2 can be used. In this embodiment copper tape was used for Fig1,2. and Fig1,8.

The Circuit Board Fig1,3 if for the demonstration embodiments only; actual products using this patent will most likely be paper or plastic with printed electronics.

As most circuits require a DC power source the UHF RF signal can be rectified by the optional diodes shown Fig1,4. High frequency Schottky diodes were used in the Embodiments.

The voltage on the LED is clamped by the RED LED from about 1.4V and at this point DC current will flow through the LED as long as enough radio energy is available to be harvested. The voltage will reach about 1.6V at higher RF power levels and the current will then increase rapidly which will light the LED brightly.

With high power 866MHz and 915MHz RFID GEN2 bands opening up around the world the LED can be lit from more than a meter away from a 2W ERP transmitter and as the polar plot of the embodiments is almost omni directional a bottle can have a display on the front whilst being lit from an antenna behind. In combination the energising field can also flash the LED or display and at the same time read a tag on the bottle to provide a good ‘tag not seen’ security system.

The RF signal can flow easily into the fluid using the capacitive plate Fig1,8; this again is stick on copper tape in both embodiments. As the fluid level Fig1,6 is above the capacitive plate Fig1,8 or Fig2,5 the RF signal couples directly into the fluid which acts as the ground for the circuit above, as described earlier.

The capacitive coupling to the fluid is greatly enhanced by the dielectric properties of the glass which helps to give a very good RF connection by increasing the capacitance and hence increasing the coupling. Obviously, with plastic bottles the distance is far less and so again this increases capacitance; the plate Fig1,8 can easily give an adequate RF connection to the fluid in both cases as the capacitance is inversely proportional to the thickness of the container material and proportional to the materials dielectric constant.

The embodiment shown in Figurel will still function with the fluid level Fig1,6 inside the capsule Fig1,1; however, performance is reduced depending on how much fluid is capacitive connected to the inside of the capsule. This fluid presents itself as a resistive path across the circuit Fig1,3 and so reduces the current flowing to the circuit being powered. This can be overcome, if required, by creating an insulating gap in the foil capsule above the fluid level (cork or stopper level). The circuit Fig1,3 can then be placed across this insulating gap to gain back full performance. This method also has the advantage of providing full power to the circuit requiring power when the bottle is on its side. It has the one disadvantage that the capsule needs to be customised.

The embodiment shown in Figure 2 is enhanced if the antenna reaches over the top of the bottle. With this enhancement the end on read null is reduces and the circuit on the bottle can still be powered effectively from a radio source above the bottle. This is ideal when large numbers of vessels are tightly packed in cardboard containers, for example in pharmaceutical shipments.

The effects of both embodiments can be made much more visible using a flashing circuit. The LEDs average power will then be less; also capacitors can be used to store energy between LED flashed to give more range or brightness.

In another embodiment the connection between the capsule Fig1,1 and the circuit board Fig1,3 was replaced by a common Gen2 RFID near field tag. This embodiment lit the flashing LED as the TAG identity was read by the interrogator.

The circuits which can be powered by this harvesting method are too numerous to include in this patent; however, for example a piezo sounder could be made to sound when the vessel is in the RF field or super-caps can be charges to change displays or even play recorded voice; it is also possible for the power to be used to drive a temperature sensor or other sensor which can then report the measurement back to the system via the UFIF RFID tag or directly by some other means.

Many low power displays are now on the market which take micro amps of current to change state. Low power LCD for example or more recently Monochrome active matrix technology which only uses power when the display is changed, these would be ideal for use with this new invention. Other electro chemical displays could also make good use of this UFIF energy harvesting invention.

The results from the Demonstration Embodiments show that the LED current would go from a few micro amps at distance to over 10mA at close range.

Claims

1. A UHF RF energy harvesting method for a container with liquid has an RF collector to receive transmitted power and a capacitive connection through the insulating container to the fluid in the container to create current flow through any device requiring power which is placed between the RF collection means and the capacitive connection means to the fluid.

2. An RF energy harvesting method as in claim 1 where the RF energy collector is the metallic foil which forms the capsule for a vessel.

3. An RF energy harvesting method as in claim 1 which uses an antenna structure to collect the radio energy instead of the conductive capsule on the vessel.

4. An RF energy harvesting method as in claim 1 which uses a second capacitive coupling means to collect radio energy from the capsule instead of a direct connection.

5. An RF energy harvesting method as in claim 1 and Claim 3 which uses a second capacitive connection means to couple to an antenna.

6. An RF energy harvesting method as in any previous claim which uses a diode rectifier to create DC power for the device which is required to be powered by the harvested radio energy.

7. An RF energy harvesting method as in any previous claim which uses a diode detector to create DC power for the device to be powered.

8. An RF energy harvesting method as in any previous claim where the device to be powered is a radio identification transponder of any type.

9. An RF energy harvesting method as in any previous claim which uses a capacitor or super-cap to store the energy collected by this method.

10. An RF energy harvesting method as in any previous claim where the device to be powered is a display of any type.

11. An RF energy harvesting method as in any previous claim where the device to be powered is an audio device of any type.

12. An RF energy harvesting method as in any previous claim where the device to be powered measures temperature.

13. An RF energy harvesting method as in any previous claim where the device to be powered measures Vibration.

14. An RF energy harvesting method as in any previous claim where the device to be powered measures humidity.

15. An RF energy harvesting method as in any previous claim where the capsule of the vessel is replaced with a metal cap or lid.

16. An RF energy harvesting method as in any previous claim where the capsule on the vessel has an insulating gap with this invention placed across this insulation gap.

17. An RF energy harvesting method as in any previous claim where the capsule on the vessel has been replaced by conductive areas of any kind to simulate the effect of the capsule

18. An RF energy harvesting method as in any previous claim where the capsule is replaced by an area of metal connected to the circuit to be powered.

19. An RF energy harvesting method as in any previous claim where the circuit to be powered is used with an RFID tag either in a series or parallel configuration.

20. An RF energy harvesting method as in the description and all prior claims where the current flow through the device to be powered is disrupted by damaging the signal path by any means.

21. An RF energy harvesting method as in the description and all prior claims where the device to be powered signals that a tamper event has taken place by any means.

21. An RF energy harvesting method as in the description and all prior claims where the device to be powered signals that a tamper event has taken place by any means. CLAIMS

1. A UHF RF energy harvesting method for a container with liquid has an RF collector to receive transmitted power and a capacitive connection through the insulating container to the fluid in the container to create current flow through any display device requiring power which is placed between the RF collection means and the capacitive connection means to the fluid.

10.An RF energy harvesting method as in any previous claim where the device to be powered is a display of any type.

15.An RF energy harvesting method as in any previous claim where the capsule of the vessel is replaced with a metal cap or lid.

17. An RF energy harvesting method as in any previous claim where the capsule on the vessel has been replaced by a conductive areas of any kind to simulate the effect of the capsule.