Apparatus and method for communicating with an RFID transponder
View Patent ↗A system having a UHF RFID transceiver is adapted to communicate exclusively with a single electro-magnetically coupled transponder located in a predetermined confined transponder operating region. The system includes a near field coupling device comprising a plurality of lines connected in parallel with an unmatched load. The near field coupling device may be formed, for example on a printed circuit board with a plurality of electrically interconnected traces and a ground plane. The system establishes, at predetermined transceiver power levels, a mutual electro-magnetic coupling which is selective exclusively for a single transponder located in a defined transponder operating region. Also included are methods for selective communication with the transponder in an apparatus such as a printer-encoder.
1. A method of communicating with a transponder on a carrier substrate in a printer, comprising:
energizing a transceiver to a first power level and writing first data to the transponder while the transceiver is energized at the first power level, wherein the first power level is independent of a writing frequency of a writing wireless signal used to write the first data; and
energizing the transceiver to a second power level that is independent of a reading frequency of a reading wireless signal and reading second data from the transponder while the transceiver is energized at the second power level, the second power level is different from the first power level.
2. The method according to claim 1 , wherein the second power level is lower than the first power level.
3. The method according to claim 1 , further comprising comparing the second data to the first data, the second data including at least a portion of the first data, and thereby determining a defective characteristic of the transponder.
4. The method according to claim 1 , wherein:
said energizing the transceiver to the first power level comprises writing to a first spatial region; and
said energizing the transceiver to the second power level further comprises reading from a second spatial region, the second spatial region is substantially similar to the first spatial region.
5. The method according to claim 1 , wherein:
said energizing the transceiver to the first power level comprises writing to a first spatial region; and
said energizing the transceiver to the second power level further comprises reading from a second spatial region, the second spatial region is of substantially equal area as the first spatial region.
6. The method according to claim 1 , wherein said energizing the transceiver to the first power level comprises writing to the transponder independent of writing to other transponders on the carrier substrate, and wherein said energizing the transceiver to the second power level comprises reading from the transponder independent of reading from the other transponders on the carrier substrate.
7. The method according to claim 1 , further comprising storing values characteristic of a plurality of read power levels and write power levels, each of the read power levels and write power levels being associated with a characteristic of at least one of the transponder and the carrier substrate, wherein each of said energizing the transceiver to the first power level and said emerging the transceiver to the second power level comprises energizing the transceiver at one of the read power levels and write power levels according to the characteristic of at least one of the transponder and the carrier substrate.
8. The method according to claim 1 , wherein said energizing the transceiver to the first power level comprises repeating said energizing the transceiver to the first power level using a power level different than the first power level.
9. The method according to claim 8 , wherein said repeating comprises energizing the transceiver to a higher power level than said first power level.
10. The method according to claim 8 , wherein said energizing the transceiver to the first power level comprises writing to the transponder at the writing frequency and wherein said repeating comprises writing to the transponder at a second frequency that is different than the writing frequency.
11. The method according to claim 1 , wherein the first power level is greater than the second power level, and the first power level is less than three times the second power level.
12. The method according to claim 1 , further comprising:
determining rates of successful communication between the transceiver and the transponder for a plurality of power levels and for a plurality of distances between the transceiver and the transponder; and
selecting the first power level associated with a relatively high rate of successful communication between the transceiver and the transponder for a limited range of distance between the transceiver and the transponder.
13. The method according to claim 12 , wherein said determining rates of successful communication comprises:
determining a plurality of read success rates and a plurality of write success rates for the plurality of power levels and for the plurality of distances between the transceiver and the transponder, and
selecting a select distance, the first power level, and the second power level, wherein the first power level is associated with a relatively high write success rate at a limited range of distances including the select distance and wherein the second power level is associated with a relatively high read success rate at a limited range of distances including the select distance.
14. The method according to claim 1 , wherein said energizing the transceiver to the first power level to write the first data to the transponder occurs before said energizing the transceiver to the second power level to read the second data from the transponder.
15. The method according to claim 1 , wherein said energizing the transceiver to the first power level to write the first data to the transponder occurs after said energizing the transceiver to the second power level to read the second data from the transponder.
16. A method of communicating with a transponder on a carrier substrate in a printer, comprising:
energizing a transceiver to a plurality of power levels with the transceiver disposed at a plurality of distances from at least one transponder to thereby communicate with the transponder, wherein each of the power levels is independent of frequency;
determining rates of successful communication between the transceiver and the transponder for the plurality of power levels and for the plurality of distances between the transceiver and the transponder; and
selecting a first power level associated with a relatively high rate of successful communication between the transceiver and the transponder for a limited range of distances between the transceiver and the transponder.
17. The method according to claim 16 , wherein said determining rates of successful communication comprises determining a plurality of read success rates and a plurality of write success rates for the plurality of power levels and for a plurality of distances between the transceiver and the transponder, and further comprising selecting a select distance, the first power level, and a second power level, the first power level being associated with the relatively high write success rate at the limited range of distances including the select distance and the second power level being associated with relatively high read success rate at the limited range of distances including the select distance.