DUAL-FREQUENCY RFID TAG WITH ISOLATED INPUTS

• US 20110285511A1
• Filed: 08/02/2011
• Published: 11/24/2011
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Impinj, Inc.
• Original Assignee: Impinj, Inc.
• Inventors: Oliver, Ronald A., Diorio, Christopher J., Maguire, Yael
• Granted Patent: US 9,087,281 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G06K 19/0724 the arrangement being a circuit for communicating at a plurality of frequencies, e.g. for managing time multiplexed communication over at least two antennas of different types
• 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: 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 1/248 provided with an AC/DC converting device, e.g. rectennas
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H04Q 2213/095 User access; PIN code

Abstract

An Integrated Circuit (IC) for an RFID tag includes two electrically isolated antenna ports for connecting to two antennas, with each antenna port configured to operate at a different frequency range and/or with a different communications protocol. In some embodiments a rectifier coupled to one of the antenna ports is operable to extract energy from an electromagnetic field in a first frequency range, and a demodulator coupled to the other antenna port is operable to demodulate symbols according to an RFID protocol in a second frequency range. In some embodiments the frequency ranges are disjoint, intersecting, or one is a proper subset of the other. In some embodiments each port is coupled to its own rectifier and/or its own modulator and/or its own demodulator. In some embodiments an RFID tag includes the IC and two antennas, each operable in one of the two frequency ranges.

Claims

1. A Radio Frequency Identification (RFID) tag configured to communicate with an RFID reader, the tag comprising:

an Integrated Circuit (IC) including a first antenna port and a second antenna port;

a first antenna configured to operate at a first frequency range and coupled to the first port; and

a second antenna configured to operate at a second frequency range and coupled to the second port;

wherein

the first port and the second port are electrically isolated and the first frequency range is substantially different from the second frequency range.

2. The RFID tag of claim 1, wherein at least one of the first antenna and the second antenna comprise at least one of:

a patch, a slot, a dipole, a loop, a coil, a spiral, and a horn.

3. The RFID tag of claim 1, wherein the first frequency range is one of:

disjoint with the second frequency range;

intersecting with the second frequency range, wherein the first frequency range extends into the second frequency range; and

a proper subset of the second frequency range, wherein the first frequency range is a narrower subset of the second frequency range.

4. The RFID tag of claim 1, wherein the IC further includes a first rectifier coupled to the first port and a second rectifier coupled to the second port.

5. The RFID tag of claim 4, wherein the first rectifier is configured to operate in the first frequency range and the second rectifier is configured to operate in the second frequency range.

6. The RFID tag of claim 1, wherein the IC further includes a first demodulator coupled to the first port and a second demodulator coupled to the second port.

7. The RFID tag of claim 6, wherein the first demodulator is operable to demodulate symbols according to a first protocol and the second demodulator is operable to demodulate symbols according to a second protocol.

8. The RFID tag of claim 1, wherein the IC further includes a first modulator coupled to the first port and a second modulator coupled to the second port.

9. The RFID tag of claim 8, wherein the first modulator is operable to modulate symbols according to a first protocol and the second modulator is operable to modulate symbols according to a second protocol.

10. The RFID tag of claim 1, wherein the IC further includes a rectifier coupled to the first port configured to extract energy from an electromagnetic field in the first frequency range, and a demodulator coupled to the second port configured to demodulate symbols received in the second frequency range according to an RFID protocol.

11. The IC of claim 10, wherein the rectifier and the demodulator are configured to operate simultaneously.

12. The RFID tag of claim 1, wherein the first and second antennas are formed on a common substrate.

13. An Integrated Circuit (IC) for a Radio Frequency Identification (RFID) tag configured to communicate with an RFID reader, the IC comprising:

a first antenna port;

a second antenna port electrically isolated from the first antenna port;

a first rectifier configured to operate at a first frequency range; and

a second rectifier configured to operate at a second frequency range substantially different from the first frequency range.

14. The IC of claim 13, wherein the first frequency range is one of:

disjoint with the second frequency range;

intersecting with the second frequency range, wherein the first frequency range extends into the second frequency range; and

a proper subset of the second frequency range, wherein the first frequency range is a narrower subset of the second frequency range.

15. The IC of claim 13, wherein the first rectifier is coupled to the first port and the second rectifier is coupled to the second port.

16. The IC of claim 13, further comprising a demodulator coupled to the first port.

17. The IC of claim 16, wherein the demodulator is configured to demodulate symbols received in the first frequency range according to an RFID protocol and the second rectifier is coupled to the second antenna port and configured to extract energy from an electromagnetic field in the second frequency range.

18. The IC of claim 13, further comprising a first modulator coupled to the first port and a second modulator coupled to the second port.

19. The IC of claim 18, wherein the first modulator is configured to modulate symbols according to a first protocol and the second modulator is configured to modulate symbols according to a second protocol.

20. An Integrated Circuit (IC) for a Radio Frequency Identification (RFID) tag configured to communicate with an RFID reader, the IC comprising:

a first antenna port;

a second antenna port electrically isolated from the first antenna port;

a first demodulator configured to demodulate symbols according to a first protocol; and

a second demodulator configured to demodulate symbols according to a second protocol different from the first protocol.

21. The IC of claim 20, wherein the first demodulator is coupled to the first port and the second demodulator is coupled to the second port.

22. The IC of claim 21, further comprising a first rectifier coupled to the first port and a second rectifier coupled to the second port, wherein the first rectifier and the second rectifier are configured to operate at substantially different first and second frequency ranges.

23. The IC of claim 22, wherein the first frequency range is one of:

disjoint with the second frequency range;

intersecting with the second frequency range, wherein the first frequency range extends into the second frequency range; and

a proper subset of the second frequency range, wherein the first frequency range is a narrower subset of the second frequency range.