Transponding tag and method
US5430441A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 1993 |
| Grant date | Jul 4, 1995 |
| Priority date | — |
| Expiry date | Oct 12, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q13/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A transponding tag (14) and method for responding with a unique code signal (18) when it receives an interrogation signal (16). The tag (14) waits a random duration before responding to avoid interference with response code signals (18) from other tags (14). The tag (14) includes two antennae (22, 24) formed on opposing sides of a dielectric planar substrate (20). A protective coating (52) and printed indicia (72) overlie the antennae. An electrical circuit (34), decoupling capacitor (44) and inductive pickup coil (46) are embedded within the substrate (20). The electrical circuit (34) and capacitor (44) reside between the antennae (22, 24) to receive RF shielding from the antennae and to reduce thickness of the tag (14). A capacitance exists between the antennae (22, 24). This capacitance stores DC electrical energy for the electrical circuit (34). The tag (14) is programmed through a modulated magnetic field detected at the inductive pickup coil (46).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.