The application of 8-12 GHz magnetic absorbing materials can be divided into two aspects: military and civilian

In terms of military use, for exampleFerrite absorbing materialIt has been widely used in stealth technology, with the characteristics of strong absorption, wide frequency band, and low cost, but it also has the disadvantages of high density and poor high-temperature characteristics. At present, the coating type absorbing materials with practical value are magnetic loss coatings or film layers made of magnetic compounds such as ferrite or carbonyl iron as absorbers and natural rubber or synthetic rubber as substrates. This type of material can not only be used to suppress mirror echoes, but also to suppress traveling waves, crawling waves, and edge diffraction echoes.
The absorption effect of such materials is closely related to the frequency of the incident wave and the thickness of the coating. Taking the products currently available both domestically and internationally as an example, coatings with a thickness of 1.5-2mm can achieve peak absorption rates of 98% -99% at selected frequencies between 8-12 GHz. Outside of the two peaks, it can absorb 90% -97%. There is another type of thin product, which is a thin film with a thickness of 0.5-1.5mm. It can achieve 97% absorption at 10-12GHz, and when it drops to 6GHz or rises to 16GHz, the absorption decreases to 75%.Coating type absorbing materialThe advantage is that RCS reduction can be achieved without changing the shape of the aircraft.

Microwave anechoic chambers made of magnetic absorbing materials can be widely used for interference of electronic devices, measurement of characteristic impedance coupling of antennas, missiles, aircraft, and satellites in radar or communication equipment, measurement of directional patterns of back shoulder antennas for astronauts, installation testing and adjustment of spacecraft, etc; In addition, magnetic absorbing materials have broad potential in improving the compatibility of airborne and shipborne radar equipment and enhancing overall performance.

On the surface of various military equipmentCoating magnetic medium absorbing materialThis can eliminate the tracking of the equipment by the radar, making it easy for these military equipment to break through the enemy's radar defense zone and defeat the enemy. It is not only a powerful means of anti radar reconnaissance, but also a way for military equipment to avoid being destroyed by infrared and laser guided weapons. In addition, absorbing materials can also be used for concealed landing and other airport navigation equipment, as well as other ground terminal equipment, ship masts, decks, submarine periscope brackets or ventilation pipelines. This is stealth equipment, which has been used in actual combat during the Gulf War and will have broader and more extensive application space in the future military field.

In terms of civilian use, with the rapid development of the telecommunications industry, the application of absorbing materials has broken through the military stealth category and penetrated into many fields such as communication anti-interference, electronic information confidentiality, environmental protection, and human body protection.

As is well known, electronic and electrical equipment not only generate electromagnetic interference, but also cause electromagnetic pollution to the ecological environment. It mainly comes from various electrical devices around us, such as color TVs, mobile phones, mother and child telephones, computers, refrigerators, and transmission stations of various telecommunications systems. Its interference and harm to scientific measurement, hospitals, navigation systems, and electronic systems in various important engineering projects can cause huge economic losses. IfMagnetic medium absorbing materialApplied in electronic devices, it can absorb both external electromagnetic radiation interference and leaked electromagnetic radiation, achieving the elimination of electromagnetic interference (electromagnetic pollution), purifying human living space, and avoiding huge economic losses to society.

We know that electromagnetic radiation causes direct and indirect harm to the human body through thermal, non thermal, and cumulative effects. Applying absorbing materials to household appliances such as televisions, speakers, computers, game consoles, microwave ovens, VCD players, mobile phones, etc. can reduce their electromagnetic wave leakage to below the national health and safety limit (less than 38 microwatts per square centimeter), ensuring people's physical health. Applying it to high-power radar, microwave medical devices, and microwave crushers can prevent their electromagnetic radiation leakage and protect operators from electromagnetic radiation injuries.

The development of modern telecommunications industry has made all our communication methods related to electromagnetic waves; The advent of the internet information age has made electronic currency and paperless trade a reality; How to prevent electromagnetic wave leakage and ensure information security has become a focus of attention in this field. The application of absorbing materials can effectively solve these problems and provide a more reliable guarantee for the implementation of China's "Golden Bridge, Golden Card, Golden Pass, and Golden Tax" projects.

The electric vehicle industry, as the development direction of the current automotive industry, has been put on the global economic strategic agenda by major automobile manufacturers. However, although replacing internal combustion engines with electric motors has solved the chemical pollution of automobile exhaust, the physical pollution caused by the use of electric motors - electromagnetic pollution - is also a thorny problem that humans must solve. The application of magnetic absorbing materials has made electronic and electric vehicles more advanced, safer, and more environmentally friendly.

The production of devices and absorbing materials used to reduce electromagnetic interference is increasing day by day, and new products are constantly emerging. Metal and alloy series absorbing materials have also attracted much attention due to their absorption bandwidth and simple process. In recent years, the Technical Development Institute of Daido Special Steel Company in Japan has developed various productsElectromagnetic wave absorbing materialsTo meet the needs of the market, FeCr series electromagnetic stainless steel was initially used. Flat powder and polyester rubber were mixed and rolled into thin sheets to form a soft rubber containing two phases, which can absorb electromagnetic waves of several hundred MHz with a maximum attenuation of -20dB.
In order to meet the needs of waveguide impedance matching and coupler in modulation amplification in microwave communication, Datong Company has developed Fe7Cr9AI soft magnetic metal powder (average particle size 15 μ m) added to polyvinyl chloride and mixed and rolled into thin plates. This material can adjust the filling rate and plate thickness of the alloy powder according to the needs of different frequencies, meeting the maximum attenuation rate in the frequency range of 10GHz~28GHz.
Subsequently, various heat-resistant thin films (known as DPR-HT, HTY, HTZ) were successfully developed, which were mixed with metal powder (Fe Si Al) and rubber, and then rolled into thin films with a thickness of 100-200 μ m, or directly liquefied into slurry and coated on the device to absorb electromagnetic waves. The operating temperature can reach over 100 ℃. The resistivity is as high as 10-108 Ω· cm. Due to its light weight, softness, and good absorption, it has been widely used in CCD charge couplers and LCD video cable lines for mobile phones, computer CPUs, CD-R, CD-RW, and digital cameras, and has considerable market prospects.
Other companies are not willing to fall behind and are engaged in the research and production of absorbing materials. TDK company uses FeSi series alloy powder to produce an absorbing material called "IR-L", which can meet the absorption requirements of high video frequency range from 10MHz to 10GHz. After mixing FeSiAl metal magnetic powder with resin and rolling it into approximately 1mm plates, a 7-8dB attenuation effect can be obtained. Another example is Tokin's development of an electromagnetic wave absorbing sheet, which uses several micrometer FeSiAl alloy flakes mixed with organic solvents and coated on a polymer film to form an absorbing sheet. It is claimed to absorb radiation ranging from 300MHz to 3GHz.

These thin absorbing materials are mainly used for devices that have adopted anti EMI measures but still do not fully meet radiation standards, and their effectiveness is particularly evident. The application of this thin absorbing sheet can reduce radiation by 3-5 dB. Composite materials with absorbing structures not only have good absorption properties, but also have good rigidity, moisture resistance, and high temperature resistance. Now, composite materials with absorbing structures are being used in mechanical foundation devices and ship and vehicle transmission equipment that generate large vibrations to reduce vibration noise, making them excellent sound-absorbing materials.