EAS system with alternating on/off transmitter operation and loop antenna
US5327118A · kind A · utility
32Cited by
1References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1993 |
| Grant date | Jul 5, 1994 |
| Priority date | — |
| Expiry date | Sep 8, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2474
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
In an EAS system 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.