RFID system utilizing parametric reflective technology

• US 20050280504A1
• Filed: 06/21/2005
• Published: 12/22/2005
• Est. Priority Date: 06/22/2004
• Status: Active Grant

• Current Assignee: Vubiq Networks, Inc.
• Original Assignee: Vubiq, Inc.
• Inventors: Pettus, Michael Gregory
• Granted Patent: US 7,460,014 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G01S 13/751 wherein the responder or reflector radiates a coded signal
• CPC Class Codes: G01S 13/9064 Inverse SAR [ISAR]
• CPC Class Codes: G01S 13/9076 Polarimetric features in SAR
• CPC Class Codes: G06K 19/067 Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 7/00 Methods or arrangements for sensing record carriers, e.g. for reading patterns methods or arrangements for marking the record carrier in digital fashion G06K1/00; pattern recognition G06F18/00; arrangements for image or video recognition or understanding G06V10/00; character recognition, recognising digital ink or document-oriented image-based pattern recognition G06V30/00
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 21/245 provided with means for varying the polarisation polarising devices H01Q15/24; tracking by comparing linear polarisation compounds G01S3/146; reducing depolarisation effects H04B7/00; polarisation diversity H04B7/10

Abstract

A system and method for encoding and decoding information by use of radio frequency antennas. The system includes one or more interrogator devices and RFID data tags. The RFID data tags include a plurality of antenna elements which are formed on a substrate or directly on an object. The antenna elements are oriented and have dimensions to provide polarization and phase information, whereby this information represents the encoded information on the RFID tag. The interrogator device scans an area and uses radar imaging technology to create an image of a scanned area. The device receives re-radiated RF signals from the antenna elements on the data tags, whereby the data tags are preferably represented on the image. The re-radiated RF signals preferably include polarization and phase information of each antenna element, whereby the information is utilized using radar signal imaging algorithms to decode the information on the RF data tag.

Claims

1. A method for reading data stored in an RF data tag, the method comprising:

transmitting electromagnetic radiation at a predetermined polarization to a scanned area, wherein an RF data tag in the area having an antenna element with polarization and phase parameters re-radiates electromagnetic radiation;

receiving the re-radiated electromagnetic radiation;

determining the polarization and phase parameters of the antenna element from the received electromagnetic radiation; and

converting the polarization and phase parameters into data representative of information encoded in the RF data tag.

2. The method of claim 1 wherein determining further comprises calculating elevation and azimuth compression data from the polarization and phase information to identify the RF data tag.

3. The method of claim 1 wherein determining further comprises performing a signal image processing algorithm to the received electromagnetic radiation to calculate the polarization and phase characteristics.

4. The method of claim 1 further comprising producing an image of the scanned area in which the electromagnetic radiation is transmitted and received, wherein the antenna element is present in the image.

5. The method of claim 1 wherein the re-radiated electromagnetic radiation of the RF data tag is received while the RF tag is moving.

6. The method of claim 1 further comprising varying frequency of the transmitted electromagnetic radiation.

7. The method of claim 1 wherein transmitting is performed from a plurality of separate transmitting and receiving sites which are synchronized.

8. A method for encoding information into an RF data tag comprising:

converting information to be encoded into a predetermined bit coding scheme;

converting the bit coding scheme into at least one of a phase characteristic and a polarization characteristics; and

producing an antenna element having the at least one of the phase and polarization characteristics.

9. The method of claim 8 further comprising printing the antenna element on a substrate.

10. The method of claim 8 wherein the antenna element is adapted to re-radiate electromagnetic radiation having the at least one phase and polarization characteristics when receiving incident electromagnetic radiation at a predetermined frequency.

11. The method of claim 8 wherein the antenna element has an orientation and at least one dimension associated with the at least one of the polarization and phase characteristics.

12. The method of claim 8 wherein the antenna element is a reference antenna element.

13. The method of claim 8 wherein the antenna element is adapted to re-radiate an RF signal upon receiving an incident RF signal, wherein the re-radiated RF signal is able to be processed to decode the encoded information in the RF data tag.

14. A method for reading data stored in an RF tag the method comprising:

transmitting a plurality of RF signals, wherein at least two RF signals in the plurality have different polarization characteristics;

receiving a plurality of re-radiated RF signals from an RF data tag having an antenna element with polarization and phase information, wherein each re-radiated RF signal is associated with a corresponding transmitted RF signal and includes polarization information of the antenna element;

comparing the polarization information for each re-radiated RF signal to identify the antenna element; and

converting the polarization and phase information of the identified antenna element into data representative of information encoded in the antenna element.

15. The method of claim 14 further comprising storing the polarization and phase information for each received RF signal.

16. The method of claim 14 wherein comparing further comprises calculating elevation and azimuth compression data from the polarization and phase information to identify the RF data tag.

17. The method of claim 14 further comprising performing a signal image processing algorithm to the re-radiated RF signals to determine the polarization and phase information.

18. The method of claim 14 further comprising producing an image of the scanned area in which the electromagnetic radiation is transmitted and received, wherein the antenna element is present in the image.

19. The method of claim 14 wherein transmitting is performed in at least one of a radial motion and a translational motion.

20. The method of claim 14 wherein transmitting is performed from a plurality of separate transmitting and receiving sites which are synchronized.