Pseudo-passive transponder device
US5822683A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1996 |
| Grant date | Oct 13, 1998 |
| Priority date | — |
| Expiry date | Apr 5, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0723
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a wireless transponder system. The transponder system includes a transponder device which is capable of operating over a relatively long range without the need for frequent battery replacements. The transponder device includes both an antenna means and a signal modification means. The signal modification means is operative for modulating an interrogation signal received from a reader device. The modulation means may utilize low power switching components that allow it to operate continuously while drawing very little current from an internal battery. In this way, the battery within the transponder will not become prematurely drained and can last up to substantially the shelf-life of the battery. In one embodiment, the transponder of the present invention utilizes a retrodirective array antenna for achieving increased antenna gain in the direction of a reader device, and therefore increased range, without an associated reduction in effective antenna coverage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.