RFID system with multiple reader transmit frequencies
US8692654B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 2012 |
| Grant date | Apr 8, 2014 |
| Priority date | — |
| Expiry date | Sep 22, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/07327
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An RFID system includes an RF-blocking enclosure having a port with a selected shortest dimension. An active RFID tag including a controller and an interior antenna coupled to the controller is located in the enclosure. The tag responds to a selected RF downlink frequency range. An RFID reader located outside the enclosure simultaneously transmits directional RF signals on a plurality of frequencies corresponding to respective wavelengths smaller than the selected shortest dimension, the plurality including a carrier frequency and an interference frequency. A beat frequency is thus defined between the carrier frequency and the interference frequency and the beat frequency is within the selected RF downlink frequency range, so that the transmitted signals pass through the port and the tag responds to the beat frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.