As far as everyone knows, the absorbing material is a kind of functional composite material that mainly absorbs electromagnetic waves, eliminates the back and forth reflection of electromagnetic waves in the shielding cavity, reduces the interference of clutter to its own equipment, and effectively prevents electromagnetic radiation from harassing surrounding equipment and personnel And injury is an advanced method to eliminate electromagnetic wave pollution. According to the current market demand, the editor has sorted out several popular models:
Wedge absorbing material
The absorber used in the microwave anechoic chamber is often made into a wedge shape (the shape of a tower of gold), which is mainly composed of polyurethane foam type, non-woven fabric flame-retardant type, and silicate plate metal film assembly type. As the frequency decreases (wavelength increases), the length of the absorber also increases greatly.
Only coating-type absorbing materials can be used on the surface of the aircraft, which broaden the frequency band and generally use composite coatings. For example, when the thickness of the lithium cadmium ferrite coating is 2.5mm～5mm, it can attenuate 8.5dB in the centimeter band; when the thickness of the spinel ferrite coating is 2.5mm, it can attenuate 24dB at 9GHz; the ferrite is chlorinated When the thickness of the butadiene rubber coating is 1.7mm～2.5mm, the attenuation is about 30dB at 5GHz～10GHz.
Structured Absorbing Material
Incorporating absorbent materials into engineering plastics makes them both absorbent and load-bearing, which is a direction for the development of absorbent materials.
Single-layer flat-shaped absorbing material
Its thickness is thin, light weight, but the operating frequency range is narrow.
Double-layer or multi-layer flat-shaped absorbing material
This kind of absorber can work in a wide operating frequency range and can be made into any shape. For example, in Japan, ferrite and short metal fibers are uniformly dispersed in a suitable organic polymer resin to make composite materials, and the working frequency band can be expanded by 40% to 50%. Its disadvantages are large thickness, complicated process and high cost.
Today, in order to further improve the performance of absorbent materials, our technical engineers are also studying the production of complex absorbent bodies with combinations of shapes.