RF ID tag device
US8179263B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 2005 |
| Grant date | May 15, 2012 |
| Priority date | — |
| Expiry date | Mar 23, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S7/023
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present invention aims to overcome the drawback with conventional RFID tag devices having a short communication range, and expand the communication range to several times or more that in the conventional scheme. The conventional scheme is based on equilibrium feeding/equilibrium modulation (a two-terminal circuit for antenna operation), whereas the present invention is based on disequilibrium feeding/equilibrium modulation (a three-terminal circuit for antenna operation). The conventional scheme is based on simple rectification of received RF signals, whereas the present invention employs a circuit based on a combination of a stub resonance-based, impedance transformation boosting scheme and a ladder boosting scheme. The conventional scheme is based on ASK or BPSK modulation, whereas the present invention is based on passive modulation, but can employ a QPSK modulation circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.