The dielectric absorbing material refers to a type of material that gradually changes its electrical properties along the thickness of the material to achieve loss of electromagnetic energy (released in the form of thermal energy).
The dielectric absorbing material is composed of a matrix material (organic or inorganic binder) and an electrical loss filler (carbon black, graphite, conductive particles or conductive fibers, etc.). The important physical parameters of the dielectric material are the dielectric constant and the loss tangent value (that is, the loss factor), the value of which is related to the nature of the base material filler.
The dielectric absorbing material should have a matching surface impedance similar to that of free space, so as to guide most of the electromagnetic waves into the material, and then dissipate and be absorbed therein.
According to its electrical design principles and geometric shapes, dielectric absorbing materials can be divided into multilayer absorbers and angular (round) cone absorbers. This type of material is usually thicker and has a wide absorption frequency band, and it is mostly used in microwave anechoic chambers.
The so-called absorbing material refers to a type of material that can absorb or greatly reduce the electromagnetic wave energy projected on its surface, thereby reducing the interference of electromagnetic waves. In engineering applications, in addition to requiring a high absorption rate 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.
Electromagnetic radiation causes direct and indirect damage to the human body through thermal, non-thermal, and cumulative effects. Studies have confirmed that ferrite absorbing materials have the best performance, which 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 electromagnetic wave radiation energy is absorbed, and then the electromagnetic wave energy is converted into heat energy through coupling