Sensormatic Electronics Corporation

Sylvie R Morin

Harry E Watkins

Frank Drucker

Kevin Robert Coffey

Wing Kei Ho

A harmonic-type electronic article surveillance marker includes a thin, elongated active element and flux concentrators provided at the ends of the active element. The flux concentrators have magnetic anisotropies that are oriented perpendicular to the length of the active element. The orientation of the magnetic anisotropies and the anisotropy field of the flux concentrators stabilize the switching threshold of the marker. The switching threshold level can be controlled by varying parameters such as the angle of the magnetic anisotropies relative to the length of the active element, the strength of the anisotropy field of the magnetic anisotropies, and the geometry of the active element and the flux concentrators.

EAS marker with flux concentrators having magnetic anisotropy oriented

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.

EAS system loop antenna having three loops of different area

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.

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Boca Raton, FL, United States of America

Sylvie R Morin