High permeability absorbing materials for EMC/EMI solutions

1. High permeability absorbing materials used to provide EMC/EMI solutions not only require a high real part u 'of magnetic permeability, but also hope to have a high imaginary part u "of magnetic permeability (commonly known as" high magnetic loss "). Analysis principle: A higher real part of magnetic permeability can bundle more magnetic flux from interference sources, while a higher imaginary part of magnetic permeability can effectively convert the bundled magnetic flux into latent heat consumption, thereby reducing or eliminating the electromagnetic radiation interference hazards of interference sources. Based on the information currently available to marketing personnel, the higher the real part of the magnetic permeability of the absorbing material that meets this characteristic, the better its absorption effect at relatively low frequencies, and the wider the effective absorption frequency.

2. Used to provide RFID/NFC anti metal interference solutions at frequencies of 13.56MHz and belowHigh permeability absorbing materialAt the same time as requiring a higher real part u 'of magnetic permeability, it is desirable to have a lower imaginary part u "of magnetic permeability (commonly known as" low magnetic loss "), that is, to have a higher quality factor (u'/u"). Analysis principle: A higher real part of magnetic permeability can bundle more magnetic flux of communication antenna signals, effectively reducing or eliminating the "metal eddy current" phenomenon generated when the antenna is closely attached to the metal. At the same time, a lower imaginary part of magnetic permeability u "will not cause excessive loss of communication signal energy, ensuring the response and effective recognition distance of communication recognition. At present, in the application of RFID/NFC anti metal interference,Absorbing materialWe can only provide solutions for RFID/NFC with frequencies of 13.56MHz and below. The reason is that when the magnetic permeability of general absorbing materials is above 10 MHz, the real part u 'of the magnetic permeability will rapidly decay, while the imaginary part u "of the magnetic permeability will rapidly rise.

Absorbing materials with high magnetic permeability real part u 'and low magnetic permeability imaginary part u "characteristics provide a solution for RFID/NFC anti metal interference at frequencies of 13.56MHz and below. However, the insertion of absorbing materials changes the inter line capacitance, impedance, distance (increase) between the antenna and the metal substrate, and dielectric constant of the antenna, which may cause the resonance frequency of the card reader or tag antenna to shift and affect the actual communication effect. Therefore, the company's technical personnel must understand the relevant characteristics of their own absorbing material system to guide customers to adjust the antenna resonance frequency correctly to achieve the best communication effect.
From this, it can be seen that whether absorbing materials are used in EMC/EMI or RFID/NFC applications, they 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, it is necessary to strengthen relevant application research and provide customers with "personalized" services.

In addition, in the application of electromagnetic induction wireless chargers using the Qi standard in WPC (Wireless Charging Alliance), the requirements and principles for absorbing materials are similar to those mentioned above.

At present, there are two main types of absorbing materials in this application field:Ferrite hard plate absorbing materialAnd soft magnetic alloy flexible absorbing materials. From the perspective of market applications, they almost each occupy half of the market share.

Ferrite hard plate absorbing materials have relatively higher magnetic permeability real part u '(up to about 200) and smaller magnetic permeability imaginary part u ", making them superior in application performance. At present, only sintering process can be used to achieve superior magnetic permeability performance. To reduce the negative impact of this process on its mechanical properties, the product size is limited (generally not exceeding 125mm × 125mm), resulting in high losses during processing. At the same time, due to its high brittleness, it requires high equipment for processing and preparation, and has a high scrap rate. In addition, products or products are prone to cracking during processing and storage, causing magnetic leakage and affecting actual performance. Therefore, the market acceptance is not very high.

Soft magnetic alloy flexible absorbing materialThe magnetic permeability performance is weaker compared to ferrite hard sheets, but its flexible size can meet the low loss requirements for product processing. Good product processing performance can reduce scrap rates and processing costs, so the market demand is not low.
If you need this product or would like to learn more about related issues or product information, please contact us. We will solve your problems and provide services: