Method and apparatus for verifying RFID tags
US6784789B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 1999 |
| Grant date | Aug 31, 2004 |
| Priority date | — |
| Expiry date | Jul 8, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0723
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An RFID tag verifier includes an RF interrogator that transmits a first and second interrogation signal each having a first operational characteristic that differs from the other by a known amount. The RF interrogator receives a first and second return signal corresponding to the respective interrogation signals. A processor determines a response of the RFID tag as defined by a second operational characteristic of the first and second return signals. The verifier can determine the signal strength of the return signal for varying strengths of the interrogation signal. Typically, a flat response is desired Additionally, or alternatively, the verifier can determine the response in terms of signal strength of the response signals for interrogation signals having different frequencies. In some applications frequency selectivity may be desirable. Additionally, or alternatively, the verifier can determine the response in terms of frequency for interrogation signals having varying strengths. A machine-readable symbol verifier can be coupled to, or formed as part of, the RFID verifier. A printer can be coupled to, or formed as part of, the RFID tag verifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.