How electronic tags address the anti-metal issue

How electronic tags address the anti-metal issue
For ordinary passive UHF tags, when attached to metal surfaces, due to the matching of the tag antenna's impedance, radiation efficiency and directionality change, causing the tag's reading distance to rapidly decrease and even become difficult to read. Therefore, special treatment or special labeling is required to enable application on metal surfaces.

There are generally three solutions:
1. Uses wave-absorbing materials to adhere to metal surfaces to overcome metal reflections.
2. Raise the label to a certain height to reduce the impact of metal boundary conditions.
3. Specialized anti-metal label antenna design methods are adopted.

The first two methods can restore a certain reading distance to ordinary tags to some extent, but they are not the best solutions; either performance is limited or the label thickness cannot meet practical application needs. To achieve this, some specially designed antennas can be used as tag antennas to overcome the effects of metal surfaces. Generally, metal-resistant labels refer to a special type of tag: a label specially designed to be applied to the surface of metal objects.