How does the RFID anti-metal tag achieve "no interference"
Many RFID tags need to be attached to the surface of a metal object. When a conventional passive UHF RFID tag with a dipole antenna is applied to a metal surface, the performance is drastically reduced and can not even be read effectively.
Metal objects' influence on the label antenna parameters and performance mainly come into two aspects: one is the antenna field, another is the antenna parameters (such as: impedance, S parameters, radiation efficiency).
In the field where the antenna is operated, there are the incident wave emitted by the reader and the reflected wave reflected by the metal plate, and the incident wave and the reflected wave have a certain phase difference, resulting in a certain degree of mutual cancellation between the two. In this way, the tagged antenna operating in this
environment can not sense enough current to provide energy to the tag chip, making the tag chip can not be activated to cause it fail.
And the antenna parameter changes because the antenna works on the metal surface, the metal plate as part of the antenna itself, so that even if the physical size of the antenna does not change, its impedance value, S parameters, etc. have changed, resulting in the antenna Performance degradation.
Therefore, the appropriate anti-metal label, is a prerequisite to ensure RFID system application.
So, what can solve the RFID anti-metal label interference?
1, absorbing material
Nowadays, the most common method is to paste a layer of magnetically absorbing material behind the RFID tag. The permeability of the absorbing material is usually higher than that of the metallic material, so as to change the magnetic field of the RFID tag, and adjust the label and the reader to a same frequency, it can make RFID tags to work normal.
2, producing label mold
Pad the distance between the label and the metal, with a certain distance, the impact of electromagnetic waves on the label will be relatively reduced.
3, ceramic rfid tag
Ceramic molecular gap is relatively large, will not be affected by electromagnetic interference and affect, will improve the efficiency of RFID tags reading.
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