Method for optimizing the design and implementation of RFID tags

• US 7,516,057 B2
• Filed: 04/21/2004
• Issued: 04/07/2009
• Est. Priority Date: 04/21/2003
• Status: Expired due to Fees

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Bridgelall, Raj
• Primary Examiner(s): Shah; Kamini S
• Assistant Examiner(s): Saxena; Akash
• Application Number:
  US10/830,273
• Publication Number:
  US 20050030201A1
• Time in Patent Office: 1,812 Days
• Field of Search: 703/13, 340/572.1, 340/572.4, 340/572.5
• US Class Current: 703/13
• 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

A method is provided for optimizing the design parameters of a RFID tag for use with a RFID reader in a RFID system. In the method, a desired frequency band that the RFID tag will operate in is chosen. Additionally, a maximum acceptable cost for the RFID tag, a minimum acceptable data range for the RFID tag and a minimum operating voltage for the RFID tag are chosen. For a given cost, an optimal data rate is calculated by varying a carrier modulation period of an interrogation signal generated by the RFID reader and antenna capacitance of the RFID tag. Next, an optimal range for a given operating voltage is calculated using the optimal data rate.

Claims

1. A method for optimizing the design parameters of an RFID tag for use with a RFID reader in a RFID system based on selected design constraints, the method comprising the steps of:

receiving a first desired frequency band that the RFID tag will operate in;

receiving a first desired data range between the RFID tag and the RFID reader;

receiving a first desired cost for the RFID tag;

receiving a first desired data rate for the RFID tag;

receiving a first desired operating voltage for the RFID tag;

receiving a first carrier modulation period of an interrogation signal generated by the RFID reader within a range of carrier modulation periods, wherein the range of carrier modulation periods is constrained by each of the first desired frequency band, the first desired data range, the first desired cost, the first desired data rate, and the first desired operating voltage;

varying an antenna capacitance of the RFID tag to a desired first capacitance value in conjunction with the first carrier modulation period to generate a first plurality of operating data rates for the RFID tag;

selecting a first operating data rate of the RFID system, the first operating data rate being the operating data rate of the first plurality of operating data rates nearest to the first desired data rate;

calculating a first operating data range based on the first desired operating voltage and the first operating data rate; and

displaying a representation of the first operating data rate and the first operating data range.

2. The method of claim 1, further comprising the steps of:

receiving at least one of a second desired frequency band, a second desired data range, a second desired cost, a second desired data rate, and a second desired operating voltage;

receiving a second carrier modulation period of the interrogation signal within the range of carrier modulation periods, wherein the range of carrier modulation periods is constrained by the received first or second desired frequency band, first or second desired data range, first or second desired cost, first or second desired data rate, and first or second desired operating voltage;

varying the antenna capacitance to a desired second capacitance value in conjunction with the second carrier modulation period to generate a second plurality of operating data rates;

selecting a second operating data rate, the second operating data rate being the operating data rate of the second plurality of operating data rates nearest to the second desired data rate;

calculating a second operating data range based on the received first or second desired frequency band, first or second desired data range, first or second desired cost, first or second desired data rate, and first or second desired operating voltage to determine a second operating data range and a second operating data rate; and

displaying a representation of the second operating data rate and the second operating data range.

3. The method of claim 2, further comprising the steps of

comparing the first operating data rate, the first operating data range, and the first desired cost to the second operating data rate, the second operating data range, and the second desired cost;

and

selecting a final operating data range and a final operating data rate based on the comparison, the final operating data rate being a data rate closest to the first desired data rate or the second desired data rate, and the final operating data range corresponding with the final operating data rate.

4. The method of claim 3, wherein the determining step comprises the steps of:

calculating a first vector sum for the first operating data rate, the first operating range, and the first desired cost;

calculating a second vector sum for the second operating data rate, the second operating range, and the second desired cost;

determining which of the first vector sum and the second vector sum is a smaller total vector distance from its respective desired data range, desired data rate, and desired cost; and

selecting the final operating data rate, the final operating range, and the final desired cost based on which set of operating data rate, operating range, and desired cost has a vector sum with the smaller total vector distance.

5. The method of claim 1, wherein the first desired frequency band is the ultra-high frequency band.

6. A computing device configured to optimize design parameters of an RFID tag for use with a RFID reader in a RFID system based on selected design constraints, the computing device comprising:

a first receiver configured to receiver a first desired frequency band that the RFID tag will operate in, a first desired data range between the RFID tag and the RFID reader, a first desired cost for the RFID tag, a first desired data rate for the RFID tag, and a first desired operating voltage for the RFID tag;

a second receiver configured to receive a first carrier modulation period of an interrogation signal generated by the RFID reader within a range of carrier modulation periods, the range of carrier modulation periods constrained by each of the first desired frequency band, the first desired data range, the first desired cost, the first desired data rate, and the first desired operating voltage, the second receiver in communication with the first receiver;

variable means for varying an antenna capacitance of the RFID tag to a desired first capacitance value in conjunction with the first carrier modulation period to generate a first plurality of operating data rates for the RFID tag, the variable means in communication with the second receiver;

first selection means for selecting a first operating data rate of the RFID system and in communication with the variable means, the first operating data rate being the operating data rate of the first plurality of operating data rates nearest to the first desired data rate;

first calculation means for calculating a first operating data range based on the first desired operating voltage and the first operating data rate, the first calculation means in communication with the first selection means; and

a display in communication with the first calculation means and configured to generate a representation of the first operating data rate and the first operating data range.

7. The computing device of claim 6, wherein:

the first receiver is further configured to receive at least one of a second desired frequency band, a second desired data range, a second desired cost, a second desired data rate, and a second desired operating voltage;

the second receiver is further configured to receive a second carrier modulation period of the interrogation signal within the range of carrier modulation periods, the range of carrier modulation periods being constrained by the received first or second desired frequency band, first or second desired data range, first or second desired cost, first or second desired data rate, and first or second desired operating voltage;

the variable means is further configured for varying the antenna capacitance to a desired second capacitance value in conjunction with the second carrier modulation period to generate a second plurality of operating data rates;

the first selection means is further configured for selecting a second operating data rate, the second operating data rate being the operating data rate of the second plurality of operating data rates nearest to the second desired data rate;

the first calculation means is further configured for calculating a second operating data range based on the received first or second desired frequency band, first or second desired data range, first or second desired cost, first or second desired data rate, and first or second desired operating voltage to determine a second operating data range and a second operating data rate; and

the display is further configured to generate a representation of the second operating data rate and the second operating data range.

8. The computing device of claim 7, further comprising:

comparison means for comparing the first operating data rate, the first operating data range, and the first desired cost to the second operating data rate, the second operating data range, and the second desired cost, the comparison means in communication with the first calculation means; and

first determination means for selecting a final operating data range and a final operating data rate based on the comparison, the final operating data rate being a data rate closest to the first desired data rate or the second desired data rate, and the final operating data range corresponding with the final operating data rate, the first determination means in communication with the comparison means.

9. The computing device of claim 8, wherein the first determination means comprises:

second calculation means for calculating a first vector sum for the first operating data rate, the first operating range, and the first desired cost and for calculating a second vector sum for the second operating data rate, the second operating range, and the second desired cost;

second determination means for determining which of the first vector sum and the second vector sum is a smaller total vector distance from its respective desired data range, desired data rate, and desired cost, the second determination means in communication with the second calculation means; and

second selection means for selecting the final operating data rate, the final operating range, and the final desired cost based on which set of operating data rate, operating range, and desired cost has a vector sum with the smaller total vector distance.

10. The computing device of claim 6, wherein the first desired frequency band is the ultra-high frequency band.

11. A computer-readable medium comprising instructions for optimizing the design parameters of an RFID tag for use with a RFID reader in a RFID system based on selected design constraints, the instructions, when executed by a processor, cause the processor to perform a method comprising the steps of:

receiving a first desired frequency band that the RFID tag will operate in;

receiving a first desired data range between the RFID tag and the RFID reader;

receiving a first desired cost for the RFID tag;

receiving a first desired data rate for the RFID tag;

receiving a first desired operating voltage for the RFID tag;

receiving a first carrier modulation period of an interrogation signal generated by the RFID reader within a range of carrier modulation periods, wherein the range of carrier modulation periods is constrained by each of the first desired frequency band, the first desired data range, the first desired cost, the first desired data rate, and the first desired operating voltage;

varying an antenna capacitance of the RFID tag to a desired first capacitance value in conjunction with the first carrier modulation period to generate a first plurality of operating data rates for the RFID tag;

selecting a first operating data rate of the RFID system, the first operating data rate being the operating data rate of the first plurality of operating data rates nearest to the first desired data rate;

calculating a first operating data range based on the first desired operating voltage and the first operating data rate; and

displaying a representation of the first operating data rate and the first operating data range.

12. The computer-readable medium of claim 11, further comprising instructions that cause the processor to perform the steps of:

receiving at least one of a second desired frequency band, a second desired data range, a second desired cost, a second desired data rate, and a second desired operating voltage;

receiving a second carrier modulation period of the interrogation signal within the range of carrier modulation periods, wherein the range of carrier modulation periods is constrained by the received first or second desired frequency band, first or second desired data range, first or second desired cost, first or second desired data rate, and first or second desired operating voltage;

varying the antenna capacitance to a desired second capacitance value in conjunction with the second carrier modulation period to generate a second plurality of operating data rates;

selecting a second operating data rate, the second operating data rate being the operating data rate of the second plurality of operating data rates nearest to the second desired data rate;

calculating a second operating data range based on the received first or second desired frequency band, first or second desired data range, first or second desired cost, first or second desired data rate, and first or second desired operating voltage to determine a second operating data range and a second operating data rate; and

displaying a representation of the second operating data rate and the second operating data range.

13. The computer-readable medium of claim 12, further comprising instructions that cause the processor to perform the steps of:

comparing the first operating data rate, the first operating data range, and the first desired cost to the second operating data rate, the second operating data range, and the second desired cost; and

selecting a final operating data range and a final operating data rate based on the comparison, the final operating data rate being a data rate closest to the first desired data rate or the second desired data rate, and the final operating data range corresponding with the final operating data rate.

14. The computer-readable medium of claim 13, further comprising instructions that cause the processor to perform the steps of:

calculating a first vector sum for the first operating data rate, the first operating range, and the first desired cost;

calculating a second vector sum for the second operating data rate, the second operating range, and the second desired cost;

determining which of the first vector sum and the second vector sum is a smaller total vector distance from its respective desired data range, desired data rate, and desired cost; and

selecting the final operating data rate, the final operating range, and the final desired cost based on which set of operating data rate, operating range, and desired cost has a vector sum with the smaller total vector distance.

15. The computer-readable medium of claim 11, wherein the first desired frequency band is the ultra-high frequency band.