RFID system with multiple tag transmit frequencies
US8937531B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 2012 |
| Grant date | Jan 20, 2015 |
| Priority date | — |
| Expiry date | Jun 11, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10069
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An RFID system has an active tag with one antenna inside, and one outside, an RF-blocking enclosure having a port with a selected shortest dimension. The RFID reader is located outside the enclosure and uses a selected RF read frequency range. The RFID tag simultaneously transmits on a plurality of frequencies corresponding to respective wavelengths smaller than the selected shortest dimension, so that a respective beat frequency is defined between two of the frequencies. The beat frequency is within the selected RF uplink frequency range. The tag transmits a first signal at a first one of the plurality of frequencies using the interior antenna and a second signal at a second, different one of the plurality of frequencies using the exterior antenna.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.