Attach an RFID electronic tag to the surface of a metal device and bring the reader close - the reading and writing distance is rapidly reduced to the point where it cannot be recognized at all. This is not because the label is broken, but because the metal has' eaten 'the signal.

Within the frequency range of RFID, electromagnetic waves will generate eddy currents when they encounter metal surfaces. Eddy currents generate strong electromagnetic wave reflections, and there is a phase difference between the reflected electromagnetic waves and the incident waves, resulting in mutual cancellation. At this point, the truly effective electromagnetic field rapidly decreases - the lower the resistivity of the metal material, the greater the eddy current losses generated, and the more severe the metal interference caused. When the antenna is subjected to extreme metal interference, the instructions issued by the card reader completely disappear, and the data reading result is a failure.

2、 How to 'save' RFID signals shielded by metal using absorbing materials

The working principle of RFID absorbing materials can be understood from two levels:

3、 High magnetic permeability and low magnetic loss: a pair of parameters that require precise balance

The core function of RFID absorbing materials is determined by two key parameters: the real part of magnetic permeability (μ ') and the imaginary part of magnetic permeability (μ'), as well as the loss tangent tan δ (=μ '/μ') defined by the ratio of the two.

Frequency constraint:At present, absorbing materials can only provide anti metal solutions for RFID/NFC with frequencies of 13.56MHz and below - the magnetic permeability rapidly decays and increases when it is above 10 MHz.

4、 Material System: From Ferrite to Soft Magnetic Alloy

5、 Key Performance: What Engineers Should Pay Attention to

6、 Typical application scenarios

7、 Selection considerations: from thickness to magnetic permeability

8、 Research Platinum Brand RFID Absorbing Materials

Advanced Institute (Shenzhen) Technology Co., Ltd. (referred to as "Advanced Institute Technology") was established in 2016. It is a national high-tech enterprise specializing in shielding materials, absorbing materials, flexible substrate coatings, and precious metal pastes. It has the independently registered trademark "Research Platinum".

The research platinum brand high permeability absorbing material produced by the company not only has a high real part of magnetic permeability (μ '), but also a low imaginary part of magnetic permeability (μ "), which can effectively reduce electromagnetic radiation and interference. After forming an isolation layer, it can prevent the propagation of electromagnetic waves, improve the anti-interference ability and electromagnetic compatibility of the equipment.

9、 Conclusion

The essence of RFID absorbing materials is to use high magnetic permeability materials to "build a path around the metal" for the magnetic field lines of RFID antennas. It does not change the communication protocol or amplify signal power - it only changes the spatial distribution of magnetic field lines, allowing the magnetic field that should have been "short circuited" by the metal to return to the effective area of the antenna.

Understanding the working logic of absorbing materials - focusing magnetic flux instead of amplifying signals, low magnetic loss instead of high loss - is the key to upgrading this thin film with a thickness of less than 0.1mm from an "accessory" to an "engineering solution". In scenarios such as anti metal tags, asset management, logistics tracking, and smartphone NFC, RFID absorbing materials provide the final piece of the puzzle for RFID to move from "ideal laboratory conditions" to the "real engineering world".