WIRELESS POWER HARVESTING ALONG MULTIPLE PATHS IN A REVERBERENT CAVITY

• US 20140008989A1
• Filed: 06/26/2012
• Published: 01/09/2014
• Est. Priority Date: 06/26/2012
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Bommer, Jason P., Ayyagari, Arun
• Granted Patent: US 9,853,499 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/225 used in level-measurement devices, e.g. for level gauge measurement
• CPC Class Codes: H01Q 1/28 Adaptation for use in or on aircraft, missiles, satellites, or balloons
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

An apparatus comprises a structure including a cavity that, when excited with electromagnetic energy, produces an electric field having randomized distribution of field amplitude and polarity. The apparatus further comprises a sensor within the cavity. The sensor has a plurality of antennas for wirelessly harvesting operating power along different paths within the cavity.

Claims

1. Apparatus comprising:

a structure including a cavity that, when excited with electromagnetic energy, produces an electric field having randomized distribution of field amplitude and polarity; and

a sensor within the cavity, the sensor having a plurality of antennas for wirelessly harvesting operating power along different paths within the cavity.

2. The apparatus of claim 1, wherein the cavity has changing boundary conditions.

3. The apparatus of claim 1, wherein the sensor includes a circuit for combining the power harvested from the antennas.

4. The apparatus of claim 3, wherein the sensor includes a transducer for using the combined power to perform a measurement.

5. The apparatus of claim 4, wherein the sensor further includes a data transmitter operated by the combined power.

6. The apparatus of claim 1, wherein the sensor is configured to become non-operational during an energy fade within the cavity.

7. The apparatus of claim 6, wherein the sensor stores no more than 200 microjoules of energy.

8. The apparatus to claim 1, further comprising a power supply outside of the cavity and at least one radiating element within the cavity for exciting the cavity with electromagnetic energy.

9. The apparatus of claim 1, wherein the antennas have different planes and orientations.

10. The apparatus of claim 9, wherein the antennas are spatially displaced and orthogonally oriented.

11. The apparatus of claim 10, wherein the antennas are spatially displaced by a fraction of a wavelength at frequency of the electromagnetic energy.

12. The apparatus of claim 1, wherein the antennas are tuned to different frequency bands.

13. The apparatus of claim 1, further comprising at least one additional sensor in the cavity, each additional sensor having a plurality of antennas for wirelessly harvesting operating power along different paths within the cavity.

14. The apparatus of claim 13, wherein different antennas of at least one sensor are turned to different available frequencies.

15. The apparatus of claim 13, wherein all of the antennas of at least one sensor are tuned to a specific frequency.

16. The apparatus of claim 13, wherein different sensors are turned to different frequencies to exploit a physical constraint of the cavity.

17. The apparatus of claim 1, wherein the structure includes a fuel tank.

18. The apparatus of claim 1, wherein the structure includes an aircraft passenger cabin.

19. A method comprising operating a sensor in a reverberant cavity, including:

harvesting energy incident from multiple directions and orientations within the cavity;

combining the harvested energy; and

using the combined energy to power the sensor.

20. A vehicle comprising a fuel tank;

and a fuel tank sensor mounted within the fuel tank, the sensor having a plurality of antennas for wirelessly harvesting energy along different paths within the tank.

21. An aircraft comprising a fuel tank;

and a plurality of fuel tank sensors within the fuel tank, at least some of the fuel tank sensors having a plurality of antennas for wirelessly harvesting operational power incident from multiple directions and orientations within the tank.

22. The aircraft of claim 21, wherein the fuel tank is contained within a wing box, and wherein wires penetrate spars of the wing box and terminate at radiating elements inside the fuel tank.

23. The aircraft of claim 21, further comprising a passenger cabin and a plurality of cabin sensors within the cabin, at least some of the cabin sensors having a plurality of antennas for wirelessly harvesting energy along different paths within the cabin.

24. A sensor comprising

a plurality of antennas directed along different paths, the antennas tuned to different frequencies;

a circuit for combining power harvested on the antennas, the sensor configured to become non-operational if power is not received on any of the antennas; and

a transducer for using the power from the circuit to measure a physical quantity.

25. A sensor system comprising a plurality of sensors for performing measurements of physical parameters, each sensor having a plurality of antennas and a circuit for harvesting operational energy, the antennas tuned to different frequencies.