Radio frequency identification tag antenna configurations

• US 7,102,523 B2
• Filed: 04/06/2005
• Issued: 09/05/2006
• Est. Priority Date: 02/12/2001
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Bandy, William R., Powell, Kevin J., Shanks, Wayne E., Arneson, Michael R.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US11/099,473
• Publication Number:
  US 20050174239A1
• Time in Patent Office: 517 Days
• Field of Search: 340/572.7, 340/572.8, 340/572.4, 340/572.1, 340/571, 340/568.1, 340/10.2, 340/10.3, 340/825.49, 343/872, 343/873, 343/700.MS, 257/673, 257/679
• US Class Current: 340/572.7
• 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) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to, said substrate, said IC die having first and second radio frequency (RF) input pads;

a first antenna formed on said substrate, and coupled to said first RF input pad; and

a second antenna formed on said substrate, and coupled to said second RF input pad;

wherein said IC die comprises a first modulator, a second modulator, a first charge pump, and a second charge pump;

wherein said first modulator is coupled to said first RF input pad, wherein said first modulator is configured to backscatter modulate a first symbol received from said first RF input pad with a response symbol, wherein said first modulator is configured to output said backscatter modulated first symbol to said first RF input pad;

wherein said second modulator is coupled to said second RF input pad, wherein said second modulator is configured to backscatter modulate a second symbol received from said second RF input pad with the response symbol, wherein said second modulator is configured to output said backscatter modulated second symbol to said second RF input pad;

wherein said first charge pump is coupled to said first RF input pad, said first charge pump configured to convert a first high frequency signal from said first RF input pad to a first substantially direct current (DC) voltage;

wherein said second charge pump is coupled to said second RF input pad, said second charge pump configured to convert a second high frequency signal from said second RF input pad to a second substantially direct current (DC) voltage; and

wherein said first antenna is configured to operate in a first frequency band and said second antenna is configured to operate in a second frequency band, wherein said first frequency band is different from said second frequency band.

2. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a plurality of radio frequency (RF) input pads; and

a plurality of antennas formed on said substrate, each coupled to a corresponding one of the plurality of RF input pads;

wherein said IC die comprises a plurality of modulators and a plurality of charge pumps;

wherein each modulator of said plurality of modulators is coupled to a corresponding RF input pad of said plurality of RF input pads;

wherein each charge pump of said plurality of charge pumps is coupled to a corresponding RF input pad of said plurality of RF input pads; and

wherein each of said plurality of antennas is configured to operate at a corresponding frequency band different from frequency bands of the others of said plurality of antennas.

3. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having first and second radio frequency (RF) input pads;

a first antenna formed on said substrate and coupled to said first RF input pad; and

a second antenna formed on said substrate and coupled to said second RF input pad;

wherein said IC die comprises a first modulator, a second modulator, a first charge pump, and a second charge pump;

wherein said first modulator is coupled to said first RF input pad, wherein said first modulator is configured to backscatter modulate a first symbol received from said first RF input pad with a response symbol, wherein said first modulator is configured to output said backscatter modulated first symbol to said first RF input pad;

wherein said second modulator is coupled to said second RF input pad, wherein said second modulator is configured to backscatter modulate a second symbol received from said second RF input pad with the response symbol, wherein said second modulator is configured to output said backscatter modulated second symbol to said second RF input pad;

wherein said first charge pump is coupled to said first RF input pad, said first charge pump configured to convert a first high frequency signal from said first RF input pad to a first substantially direct current (DC) voltage;

wherein said second charge pump is coupled to said second RF input pad, said second charge pump configured to convert a second high frequency signal from said second RF input pad to a second substantially direct current (DC) voltage; and

wherein said first antenna has a first orientation and said second antenna has a second orientation, wherein said first orientation is different from said second orientation.

4. The RFID tag device of claim 3, wherein the first orientation provides a substantially maximum gain for the first antenna in a first direction, and wherein the first direction correlates to a direction of non-optimum gain for the second antenna.

5. The RFID tag device of claim 4, wherein the second orientation provides substantially maximum gain for the second antenna in a second direction, and wherein the second direction correlates to a direction of non-optimum gain for the first antenna.

6. The RFID tag device of claim 3, wherein the first antenna is a first dipole antenna and the second antenna is a second dipole antenna.

7. The RFID tag device of claim 3, wherein the first orientation is at a 90 degree angle to the second orientation.

8. The RFID tag device of claim 3, wherein said first antenna is configured to operate in a first frequency band, and wherein said second antenna is configured to operate in a second frequency band.

9. The RFID tag device of claim 3, wherein said first antenna and said second antenna are configured to operate in a same frequency band.

10. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a plurality of radio frequency (RF) input pads; and

a plurality of antennas formed on said substrate, each antenna coupled to a corresponding one of the plurality of RF input pads;

wherein said IC die comprises a plurality of modulators and a plurality of charge pumps;

wherein each modulator of said plurality of modulators is coupled to a corresponding RF input pad of said plurality of RF input pads;

wherein each charge pump of said plurality of charge pumps is coupled to a corresponding RF input pad of said plurality of RF input pads; and

wherein each of said plurality of antennas has a corresponding orientation different from orientations of others of said plurality of antennas.

11. The RFID tag device of claim 10, wherein said plurality of antennas are oriented such that an average gain over all orientations of said plurality of antennas is increased with respect to each of said plurality of antennas separately.

12. The RFID tag device of claim 10, wherein each of said plurality of antennas is configured to operate in a corresponding frequency band different from the frequency band of the others of said plurality of antennas.

13. The RFID tag device of claim 10, wherein said plurality of antennas are configured to operate in a same frequency band.

14. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having first and second radio frequency (RF) input pads;

a first antenna formed on said substrate and coupled to said first RF input pad; and

a second antenna formed on said substrate and coupled to said second RF input pad;

wherein said first antenna is positioned on said substrate at distance from said second antenna, wherein said distance is approximately equal to ½

of a wavelength of a radio frequency (RF) signal of interest.

15. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a first radio frequency (RF) input pad, a second RF input pad, and a ground pad;

a first antenna formed on said substrate and coupled between said first RF input pad and said ground pad; and

a second antenna formed on said substrate and coupled between said second RF input pad and said ground pad;

wherein said IC die comprises a first modulator, a second modulator, a first charge pump, and a second charge pump,

wherein said first modulator is coupled to said first RF input pad, wherein said first modulator is configured to backscatter modulate a first symbol received from said first RF input pad with a response symbol, wherein said first modulator is configured to output said backscatter modulated first symbol to said first RF input pad;

wherein said second modulator is coupled to said second RF input pad, wherein said second modulator is configured to backscatter modulate a second symbol received from said second RF input pad with the response symbol, wherein said second modulator is configured to output said backscatter modulated second symbol to said second RF input pad;

wherein said first charge pump is coupled to said first RF input pad, said first charge pump configured to convert a first high frequency signal from said first RF input pad to a first substantially direct current (DC) voltage; and

wherein said second charge pump is coupled to said second RF input pad, said second charge pump configured to convert a second high frequency signal from said second RF input pad to a second substantially direct current (DC) voltage.

16. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a first radio frequency (RF) pad, a second RF pad, a third RF pad, and a fourth RF pad;

a first antenna formed on said substrate and coupled between said first RF pad and said second RF pad; and

a second antenna formed on said substrate and coupled between said third RF pad and said fourth RF pad;

wherein said IC die comprises a first modulator, a second modulator, a first charge pump, and a second charge pump,

wherein said first modulator is coupled to said first RF input pad, wherein said first modulator is configured to backscatter modulate a first symbol received from said first RF input pad with a response symbol, wherein said first modulator is configured to output said backscatter modulated first symbol to said first RF input pad;

wherein said second modulator is coupled to said third RF input pad, wherein said second modulator is configured to backscatter modulate a second symbol received from said third RF input pad with the response symbol, wherein said second modulator is configured to output said backscatter modulated second symbol to said third RF input pad;

wherein said first charge pump is coupled to said first RF input pad, said first charge pump configured to convert a first high frequency signal from said first RF input pad to a first substantially direct current (DC) voltage; and

wherein said second charge pump is coupled to said third RF input pad, said second charge pump configured to convert a second high frequency signal from said third RF input pad to a second substantially direct current (DC) voltage.

17. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a plurality of radio frequency (RF) input pads; and

a plurality of antennas formed on said substrate, each antenna coupled to a corresponding one of the plurality of RF input pads;

wherein each of said plurality of antennas has a corresponding orientation different from orientations of others of said plurality of antennas; and

wherein said plurality of antennas are oriented such that an average gain over all orientations of said plurality of antennas is increased with respect to each of said plurality of antennas separately.

18. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a plurality of input/output (I/O) pads, said plurality of I/O pads consisting of a first radio frequency (RF) input pad, a second RF input pad, a ground pad, and a fourth pad;

a first antenna formed on said substrate and coupled between said first RF input pad and said ground pad; and

a second antenna formed on said substrate and coupled between said second RF input pad and said ground pad.

19. A radio frequency identification (RFID) tag device, comprising:

a substrate;

an integrated circuit (IC) die mounted to said substrate, said IC die having a plurality of input/output (I/O) pads, said plurality of I/O pads consisting of a first radio frequency (RF) pad, a second RF pad, a third RF pad, and a fourth RF pad;

a first antenna formed on said substrate and coupled between said first RF pad and said second RF pad;

a second antenna formed on said substrate and coupled between said third RF pad and said fourth RF pad;

wherein said first modulator is coupled to said first RF input pad, wherein said first modulator is configured to generate a backscatter modulated first symbol that is output to said first RF input pad; and

wherein said second modulator is coupled to said third RF input pad, wherein said second modulator is configured to generate a backscatter modulated second symbol that is output to said third RF input pad.