Transponders
US6657580B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 2001 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | Dec 27, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/78
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A transponder comprises a retro-reflective antenna array in which the length of the transmission lines is given by I=±A n&lgr; where: A is an arbitrary length; n is zero, or an integer, &lgr; is the wavelength of the retro-reflected signal. The array is fabricated on a board (71) of insulating material, using microstrip techniques. Rectangular patches (not shown) form the individual antennae and these are interconnected by transmission lines (75 to 82), each of which pass through a respective modulation device (43) whereby the retro-reflected signal is modulated. A positioning/tracking system incorporating one or more modulated transponders is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.