Radio frequency identification architecture

• US 7,965,189 B2
• Filed: 04/16/2007
• Issued: 06/21/2011
• Est. Priority Date: 02/12/2001
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Shanks, Wayne E., Arneson, Michael R., Bandy, William R., Powell, Kevin J.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US11/785,215
• Publication Number:
  US 20070194933A1
• Time in Patent Office: 1,527 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.7, 340/571, 340/568.1, 340/10.2, 340/10.3, 340/10.4, 340/10.41, 343/872, 343/873, 343/700.MS, 341/53, 455/41.1
• US Class Current: 340/572.4
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 19/0713 the arrangement including a power charge pump
• 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 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• 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
• CPC Class Codes: G06K 7/10039 interrogator driven, i.e. synchronous
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: G06K 7/10108 interrogating only those RFIDs that fulfill a predetermined requirement, e.g. selecting all RFIDs having the same speed and moving in a cloud like fashion, e.g. on the same train; interrogating only RFIDs having a certain predetermined temperature, e.g. in the same fridge, another possibility being the active ignoring of a group of tags that fulfill a predetermined requirement, equivalent to the Boolean NOT operation
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G08B 13/2485 Simultaneous detection of multiple EAS tags
• CPC Class Codes: G11C 5/142 Contactless power supplies, e.g. RF, induction, or IR
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence

Abstract

A radio frequency identification (RFID) architecture is described. RFID tags are interrogated by a reader, which may be located in a network of readers. The reader transmits symbols to the tags. Tags respond to the interrogations with symbols that each represent one or more bits of data. An RFID tag includes an antenna pad, a receiver, a state machine, and a modulator. The receiver is coupled to the antenna pad. The receiver receives a symbol from the antenna pad and outputs a received signal. The state machine is configured to determine a response symbol from the received signal and an operating state of the tag. The modulator is coupled to the antenna pad. The modulator is configured to backscatter modulate the received symbol with the response symbol. The modulator is configured to output the backscatter modulated symbol to the antenna pad.

Claims

1. A radio frequency identification (RFID) integrated circuit (IC), comprising:

an antenna pad;

a sensor pad;

a state machine coupled to the sensor pad that receives sensor information from the sensor pad; and

a modulator coupled to the antenna pad, wherein the modulator is configured to backscatter modulate a carrier signal received from the antenna pad with an output value received from the state machine, wherein the modulator is configured to output the backscatter modulated symbol to the antenna pad.

2. The RFID IC of claim 1, further comprising:

an analog-to-digital converter that couples the state machine to the sensor pad, wherein the analog-to-digital converter receives the sensor information from the sensor pad, and outputs the sensor information to the state machine in digital form.

3. The RFID IC of claim 1, further comprising:

a receiver coupled to the antenna pad, wherein the receiver receives a symbol on the carrier signal from the antenna pad and outputs a received signal that is input to the state machine.

4. The RFID IC of claim 3, further comprising:

a storage unit that stores a tag identification number.

5. The RFID IC of claim 4, wherein the state machine is configured to read the stored tag identification number, wherein the state machine is configured to generate the output value using at least one bit of the read tag identification number.

6. The RFID IC of claim 3, further comprising:

a storage unit that stores the sensor information.

7. The RFID IC of claim 6, wherein the state machine is configured to read the stored sensor information, wherein the state machine is configured to generate the output value using at least one bit of the stored sensor information.

8. A radio frequency identification (RFID) integrated circuit (IC), comprising:

an antenna pad;

a sensor;

a state machine coupled to the sensor that receives sensor information from the sensor; and

a modulator coupled to the antenna pad, wherein the modulator is configured to backscatter modulate a carrier signal received from the antenna pad with an output value received from the state machine, wherein the modulator is configured to output the backscatter modulated symbol to the antenna pad.

9. The RFID IC of claim 8, further comprising:

an analog-to-digital converter that couples the state machine to the sensor, wherein the analog-to-digital converter receives the sensor information from the sensor, and outputs the sensor information to the state machine in digital form.

10. The RFID IC of claim 8, further comprising:

a data programming unit that stores the sensor information.

11. The RFID IC of claim 10, wherein the state machine is configured to read the stored sensor information, wherein the state machine is configured to generate the output value using at least one bit of the stored sensor information.

12. The RFID IC of claim 8, wherein the sensor is a gas sensor, a temperature sensor, an accelerometer, an optical sensor, a pressure sensor, a tamper sensor, an electromagnetic field sensors, a radiation sensor, or a biochemical sensor.

13. A radio frequency identification (ID) tag, comprising:

a substrate;

an antenna on the substrate;

a sensor on the substrate;

a state machine coupled to the sensor that receives sensor information from the sensor; and

a modulator coupled to the antenna, wherein the modulator is configured to backscatter modulate a carrier signal received by the antenna with an output value received from the state machine, wherein the modulator is configured to output the backscatter modulated symbol to the antenna.

14. The RFID tag of claim 13, further comprising:

an analog-to-digital converter that couples the state machine to the sensor, wherein the analog-to-digital converter receives the sensor information from the sensor, and outputs the sensor information to the state machine in digital form.

15. The RFID tag of claim 13, further comprising:

a receiver coupled to the antenna, wherein the receiver receives a symbol on the carrier signal from the antenna and outputs a received signal that is input to the state machine.

16. The RFID tag of claim 15, further comprising:

a data programming unit that stores a tag identification number.

17. The RFID tag of claim 16, wherein the state machine is configured to read the stored tag identification number, wherein the state machine is configured to generate the output value using the received signal and at least one bit of the read tag identification number.

18. The RFID tag of claim 13, further comprising:

a data programming unit that stores the sensor information.

19. The RFID tag of claim 18, wherein the state machine is configured to read the stored sensor information, wherein the state machine is configured to generate the output value using at least one bit of the stored sensor information.

20. The RFID tag of claim 13, wherein the sensor is a gas sensor, a temperature sensor, an accelerometer, an optical sensor, a pressure sensor, a tamper sensor, an electromagnetic field sensors, a radiation sensor, or a biochemical sensor.