High-permeability absorbing materials refer to a class of absorbing materials that have a relatively high magnetic permeability real part u'(generally ≥50) around 10MHz. In terms of its magnetic permeability characteristics, high-permeability absorbing materials can be roughly divided into two categories due to their application fields, that is, the different problems they solve:
1. The high permeability absorbing material used to provide EMC/EMI solutions not only requires a higher real part u′ of permeability, but also a higher imaginary part u” (commonly known as “high magnetic permeability”). Analysis principle: the higher the real part of the magnetic permeability can increase the magnetic flux of the interference source, the higher the imaginary part of the magnetic permeability can effectively convert the concentrated magnetic flux into latent heat to be consumed, thereby reducing or Eliminate the electromagnetic radiation interference hazards of interference sources. According to the analysis of the data currently available to marketers, the higher the magnetic permeability of the absorbing material that meets this characteristic, the better the absorption effect of relatively low frequency, and the more effective the absorption frequency is width.
2. High permeability absorbing materials used to provide RFID/NFC anti-metal interference solutions at frequencies of 13.56MHz and below. While a higher real part u'of permeability is required, it is hoped to have a lower permeability The imaginary part u″ (commonly known as “low magnetic loss”), that is, hope to have a higher quality factor (u′/u″). Analysis of the principle: the higher the real part of the magnetic permeability can more bundle the magnetic flux of the communication antenna signal, thereby effectively reducing or eliminating the "metal eddy current" phenomenon generated when the antenna is close to the metal, and at the same time, the lower magnetic permeability is false. The part u" will not excessively lose the energy of the communication signal passed through, ensuring the response of communication identification and the effective identification distance. At present, in the application of RFID/NFC anti-metal interference, the absorbing material can only be 13.56MHz and below Frequency RFID/NFC provides a solution. The reason: when the permeability of general absorbing materials is more than 10 MHz, the real part u′ of the permeability will rapidly decay, while the imaginary part u″ of the permeability will rise rapidly. . Absorbing materials with the characteristics of high permeability real part u'and low permeability imaginary part u” provide solutions for RFID/NFC anti-metal interference at frequencies of 13.56MHz and below. At the same time, due to the change of the insertion of the absorbing material The antenna’s line capacitance, impedance, and the distance (increase) and dielectric constant between the antenna and the metal base plate may cause the resonant frequency of the card reader or tag antenna to shift and affect the actual communication effect. Therefore, the company Technicians must understand the relevant characteristics of their own absorbing material system to guide customers to adjust the antenna resonance frequency to achieve the best communication effect. It can be seen that the absorbing materials are not in EMC/EMI or RFID/NFC. The application of this product will have more or less other impacts on the entire system of the application object. In order to improve market competitiveness, in addition to the quality of the product itself, relevant application research must be strengthened to provide customers with "personal" services.