| 摘要 |
The magnetic element part of the tag is wire, strip or band that has a length chosen to give the desired resonance at the electromagnetic signal frequency, and the element is exposed to one or more modulation fields in the detection zone, the signature(s) for which is/are detected and analysed in order to reveal the presence of the tag or its identity. The coating for the magnetic element has a higher conductivity than the element. The deactivation field has a greater amplitude than the detection field. The modulation effect is made to disappear by disturbing the magnetic properties. DETAILED DESCRIPTION - The magnetic element comprises an amorphous or nanocrystalline alloy and is designed to respond to an electromagnetic signal within a detection zone in order to reveal its presence or identity. The element is provided with a high conductivity coating except in the centre, and can be deactivated by exposing it to an electromagnetic field that heats up the uncoated centre of the element due to its higher resistance, until the crystallisation temperature is exceeded and the magnetic properties of the element are destroyed. |
