The so-called absorbing material refers to a type of material that can absorb or greatly reduce the electromagnetic wave energy received on its surface, thereby reducing electromagnetic wave interference. In engineering applications, in addition to requiring high absorption of electromagnetic waves in a wide frequency band, the absorbing material is also required to have light weight, temperature resistance, humidity resistance, and corrosion resistance.
With the development of modern science and technology, the impact of electromagnetic wave radiation on the environment is increasing. At the airport, the flight cannot take off due to electromagnetic wave interference, and it is delayed; at the hospital, mobile phones often interfere with the normal operation of various electronic diagnosis and treatment equipment. Therefore, the treatment of electromagnetic pollution and the search for a material that can withstand and weaken electromagnetic wave radiation-absorbing materials have become a major issue in materials science.
Electromagnetic radiation causes direct and indirect damage to the human body through thermal, non-thermal, and cumulative effects. Studies have confirmed that the performance of ferrite absorbing materials is very good, and it has the characteristics of high absorption frequency band, high absorption rate, and thin matching thickness. Applying this material to electronic equipment can absorb leaked electromagnetic radiation and achieve the purpose of eliminating electromagnetic interference. According to the law of electromagnetic waves propagating in the medium from low magnetic to high magnetic permeability, high magnetic permeability ferrite is used to guide electromagnetic waves, through resonance, a large amount of radiant energy of electromagnetic waves is absorbed, and then the energy of electromagnetic waves is converted into heat energy through coupling.
Two issues should be considered in the design of absorbing materials:
1. When electromagnetic waves encounter the surface of the absorbing material, pass through the surface as much as possible to reduce reflection;
2. When the electromagnetic wave enters the inside of the absorbing material, the energy of the electromagnetic wave should be lost as much as possible.