RFID tag with modifiable and reversible read range

• US 7,327,257 B2
• Filed: 12/17/2004
• Issued: 02/05/2008
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Posamentier, Joshua
• Primary Examiner(s): Goins, Davetta W.
• Application Number:
  US11/015,071
• Publication Number:
  US 20060145851A1
• Time in Patent Office: 1,145 Days
• Field of Search: 340/572.1, 340/572.4, 340/539.1, 340/539.21, 340/539.23, 340/10.1, 340/10.3, 340/10.4, 340/10.6, 342/42, 342/44
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Abstract

According to some embodiments, read range control update information is received in a radio frequency (RF) signal. The information is used to control a read range of an antenna. The read range of the antenna can be increased or deceased, for example, by changing an impedance of the antenna.

Claims

1. A system comprising

a radio frequency identification (RFID) device and an antenna coupled to the RFID device, the RFID device comprising:

a read range control circuitry coupled to the antenna;

the read range control circuitry to modify a read range of the antenna between a first read range and a second read range;

wherein the RFID device is to obtain its operating power from a radio frequency signal received through the antenna.

2. The system as recited in claim 1, the read range control circuitry to modify the read range of the antenna according to a radio frequency (RF) signal received on the antenna.

3. The system as recited in claim 1, the read range control circuitry comprising an impedance control unit to modify the read range of the antenna between the first read range and the second read range.

4. The system as recited in claim 3, the impedance control unit comprising an impedance mismatch tap.

5. The system as recited in claim 1, the read range control circuitry wherein the first read range is greater than the second read range.

6. The system as recited in claim 1, the read range control circuitry to modify the read range between three or more read range distances.

7. The system as recited in claim 1, further comprising non-volatile memory to store read range information received on the antenna.

8. The system as recited in claim 1, further comprising power harvesting circuitry coupled to the antenna to harvest power from a radio frequency (RF) signal containing read range update information.

9. The system as recited in claim 1, further comprising a modulating switch coupled to the antenna to send a read range update acknowledgement message on the antenna.

10. A method comprising:

receiving, through an antenna of a radio frequency identification (RFID) device, a radio frequency (RF) signal that provides operating power for the RFID device, the RF signal containing read range update information; and

updating a read range capability of the antenna according to the read range update information;

wherein the read range update information specifies one of two or more pre-specified read ranges.

11. The method as recited in claim 10, wherein the two or more pre-specified read ranges comprise a short read range and a long read range.

12. The method as recited in claim 10, wherein updating the read range capability comprises modifying an impedance of the antenna.

13. The method as recited in claim 10, further comprising storing the read range update information in non-volatile memory.

14. The method as recited in claim 10, further comprising authenticating the RF signal.

15. The method as recited in claim 10, further comprising decrypting the RF signal.

16. The method as recited in claim 10, further comprising sending a read range update acknowledgement message through the antenna.

21. The method as recited in claim 10, further comprising receiving a read range update acknowledgement message.

17. A method comprising:

sending a radio frequency (RF) signal containing read range update information to a radio frequency identification device that receives its operating power from the RF signal;

wherein the read range update information specifies one of two or more pre-specified read ranges.

18. The method as recited in claim 17, wherein the two or more pre-specified read ranges comprise a short read range and a long read range.

19. The method as recited in claim 17, wherein the RF signal further contains an authentication.

20. The method as recited in claim 17, wherein the RF signal is encrypted.