Antenna system and method for reading low frequency tags
US6750771B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 24, 2001 |
| Grant date | Jun 15, 2004 |
| Priority date | — |
| Expiry date | Nov 25, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10435
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A reader reads identifiers from tags on pallets conveyed past the reader. The reader includes two interleaved linear arrays of antennas with circularly polarized fields. Each antenna is composed of a pair of crossed rods phased to have adjacent antennas of an array generate circularly polarized fields of opposite rotation. The vector components of the polarization in the direction across the width of the conveyor have peaks and nulls, and the interleaved arrays are arranged such that the nulls of one array's fields are covered with the peaks of the other array's fields. This arrangement allows the reader to the identifier from the tag when the tag is at any orientation. A tag at the side of the reader is aligned in the direction of travel by rails on the conveyor. The reader has antennas aligned in the direction of travel to read such tags.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.