EAS system loop antenna having three loops of different area
US5404147A · kind A · utility
7Cited by
8References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1992 |
| Grant date | Apr 4, 1995 |
| Priority date | — |
| Expiry date | Oct 28, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2474
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An EAS system in which a transmitter alternately drives first and second antennas with the same coded message signal in its entirety. The antennas, in turn, transmit first and second signals each containing the coded message signal into respective first and second partially overlapping parts of an interrogation zone. Also disclosed is an antenna structure comprised of a plurality of loops extending one after the other and successive ones of which are of opposite phase. One of the loops circumscribes an area which is smaller than each of the other loops to realize reduced coupling to adjacent structures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.