Let you know the role of absorbing materials in anti metal RFID tag

Anti metal RFID tag, also called uhf RFID anti metal tag, is electronic tags made of absorbing materials with anti-interference functions. They effectively solve the problem of metal carriers interfering with the radio frequency signals of electronic tags attached to their surfaces.

On metal RFID tags with absorbing materials have the following characteristics:

1. Users of on metal RFID tags can customize the reading of their standard data to improve the efficiency of the application system;

2. Metal mount RFID tags have a long reading distance (the reading and writing distance is related to the RFID reader and antenna);

3. Super strong anti-interference ability;

4. Long data retention time, up to 20 years, high cost performance;

5. Multi-tag reading is not affected or limited by the number of tags in the working area;

6. RFID tags for metal surfaces adopt an ultra-wide working frequency band design, which not only complies with relevant industry regulations, but also can be flexibly developed and applied;

7. The storage area is for users to perform encrypted reading, writing, erasing and rewriting operations, and can also specify a permanent dedicated word area dedicated to users.
With the development of the Internet of Things, the application of absorbing materials in RFID tags is now very common. UHF metal tag is also used in various environments, including logistics management, warehouse management, asset management and other places. So what is the role of absorbing materials in uhf metal tag?

In the RFID frequency range, when electromagnetic waves encounter metal surfaces, due to the eddy current phenomenon, strong electromagnetic wave reflection is generated, and there is a phase difference between the reflected electromagnetic waves and the incident waves, resulting in mutual cancellation. At this time, the truly effective electromagnetic field decreases rapidly, because the lower the resistivity of the metal material, the greater the eddy current loss will be, and the more serious the metal problem caused. Therefore, when the antenna is subject to extreme metal interference, the instructions issued by the card reader will completely disappear, so the data reading result is a failure. The absorbing material mainly utilizes the high magnetic permeability property. When in use, the absorbing sheet is inserted between the circular antenna of the uhf RFID metal tag and the metal substrate, which increases the probability of the induced magnetic field passing through the absorbing material itself and reduces the probability of passing through the metal plate, thereby reducing the induced eddy current generated in the metal plate. The absorbing material further reduces the loss of the induced magnetic field. At the same time, due to the insertion of the absorbing material magnetic isolation sheet, the measured parasitic capacitance will also be reduced, and the frequency offset will be reduced, which is consistent with the resonant frequency of the card reader, thereby greatly improving the card reading effect and distance.

In the RFID frequency range, when electromagnetic waves encounter metal surfaces, due to the eddy current phenomenon, strong electromagnetic wave reflection is generated, and there is a phase difference between the reflected electromagnetic waves and the incident waves, resulting in mutual cancellation. At this time, the truly effective electromagnetic field decreases rapidly, because the lower the resistivity of the metal material, the greater the eddy current loss will be, and the more serious the metal problem caused. Therefore, when the antenna is subject to extreme metal interference, the instructions issued by the card reader will completely disappear, so the data reading result is a failure. The main use of the high magnetic permeability characteristics of the absorbing material is to insert the absorbing sheet between the uhf RFID metal tag's shaped antenna and the metal substrate, increase the probability of the induced magnetic field passing through the absorbing material itself and reduce the probability of passing through the metal plate, thereby reducing the induced eddy current generated in the metal plate, and the absorbing material further reduces the loss of the induced magnetic field. At the same time, because of the insertion of the absorbing material magnetic isolation sheet, the measured parasitic capacitance will also be reduced, the frequency offset will be reduced, and it will be consistent with the resonance frequency of the card reader, thereby greatly improving the card reading effect and distance.

Some projects in life will encounter various environments, such as high and low temperatures, liquids, cement walls, strong magnetism, metal, etc.

For example, in a metal environment, in an ultra-high frequency (UHF) radio frequency identification tag system, it is particularly difficult to identify tags attached to metal carriers because metal obstacles will reflect and interfere with electromagnetic waves. At present, there are mainly four ways to effectively solve the problem of capturing information on metal surfaces:

1. Use absorbing materials to absorb excess electromagnetic waves;

2. Pad height design;

3. The bandwidth of the tag antenna must be sufficient;

4. Grounded antenna design.

At present, our common method is to use absorbing materials and pad height in combination. The ideal method is to design an antenna with a large bandwidth and then use absorbing materials to pad height, which will achieve the best effect.