Object identification system and method
An object identification system includes a guided surface waveguide probe that produces a guided surface wave; and an object identification tag having a receive structure and a tag circuit, the tag circuit coupled to the receive structure and electrically powered as a load on the probe by conversion of the guided surface wave to electrical current at the receive structure, the tag circuit configured to emit a return signal containing a tag identifier when electrically powered by presence of the guided surface wave.
1. An object identification system, comprising:
a guided surface waveguide probe comprising a charge terminal elevated over a terrestrial medium that produces a guided surface wave by generating at least one resultant field that synthesizes a wave front incident at a complex Brewster angle of incidence (θ i,B ) of the terrestrial medium; and
an object identification tag comprising a receive structure and a tag circuit, the tag circuit coupled to the receive structure and electrically powered as a load on the probe by conversion of the guided surface wave to electrical current at the receive structure, the tag circuit configured to emit a return signal containing a tag identifier when electrically powered by presence of the guided surface wave.
2. The system of claim 1 , wherein the system further comprises a receiver that receives the return signal.
3. The system of claim 2 , further comprising a computer system operatively coupled to the receiver and that determines the tag identifier and identifies an object that was previously associated with the tag.
4. The system of claim 2 , wherein the tag is addressable and the receiver transmits an addressed message to the tag.
5. The system of claim 1 , wherein the guided surface wave has a first frequency and the return signal has a second frequency higher than the first frequency.
6. The system of claim 1 , wherein the return signal is a radio frequency (RF) signal.
7. The system of claim 1 , wherein the guided surface wave penetrates high permittivity material to power tags located therein.
8. The system of claim 1 , wherein the tag is addressable and the guided surface wave includes an addressed message for the tag.
9. The system of claim 1 , wherein the tag is addressable and, upon receipt of a message addressed to the tag, the tag circuit executes logic to carry out a function corresponding to the message.
10. The system of claim 9 , wherein the function includes reading data from a memory of the tag and transmitting a signal containing the read data.
11. The system of claim 9 , wherein the function includes storing data in a memory of the tag.
12. The system of claim 9 , wherein the function is to not transmit a return signal for at least a period of time.
13. The system of claim 9 , wherein the message is sent by a receiver configured to receive the return signal.
14. The system of claim 1 , wherein the system further comprises a computer system, the computer system configured to manage an inventory of objects for a site, each object associated with a tag and the inventory managed according to tag identifiers in return signals that are respectively received from the tags.
15. The system of claim 1 , wherein the system further comprises a computer system, the computer system configured to identify locations of objects, each object associated with a tag and the locations determined according to return signals respectively received from the tags.
16. An object identification system, comprising:
a guided surface waveguide probe that produces a guided surface wave having a frequency-dependent illumination area in which tags responsive to a frequency of the guided surface wave are powered and emit respective return signals; and
an object identification tag comprising a receive structure and a tag circuit, the tag circuit coupled to the receive structure and electrically powered as a load on the probe by conversion of the guided surface wave to electrical current at the receive structure, the tag circuit configured to emit a return signal containing a tag identifier when electrically powered by presence of the guided surface wave.
17. The system of claim 16 , wherein the guided surface waveguide probe comprises a charge terminal elevated over a terrestrial medium configured to generate at least one resultant field that synthesizes a wave front incident at a complex Brewster angle of incidence (θ i,B ) of the terrestrial medium.
18. The system of claim 16 , wherein one or more tags are queried to each return data in addition to the tag identifier.
19. The system of claim 16 , wherein one or more tags are commanded to not transmit respective return signals for at least a period of time.
20. The system of claim 16 , wherein a size of the illumination area is controlled to be non-overlapping with an adjacent second illumination area that is defined by a second guided surface wave produced by a second guided surface waveguide probe.
21. The system of claim 16 , wherein a shape of the illumination area is controlled by producing the guided surface wave to vary as a function of direction.
22. The system of claim 16 , wherein the illumination area is global.