Hello everyone, I am the editor. Today, I will introduce the absorbing materials to you. The following content is organized by the editor, and the relevant content is for reference.
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 the absorbing material to have a high absorption rate of electromagnetic waves in a wider frequency band, it is also required to have the properties of light weight, temperature resistance, humidity resistance, and corrosion resistance.
1. Stealth technology
Coating absorbing materials on various weapon equipment and military facilities such as aircraft, missiles, tanks, ships, warehouses, etc., can absorb reconnaissance radio waves and attenuate reflected signals, thereby breaking through enemy radar defenses. This is a kind of anti-radar reconnaissance. A powerful method to reduce the weapon system from being attacked by infrared guided missiles and laser weapons. For example, because the American B-1 strategic bomber is coated with absorbing material, its effective reflection cross section is only 1/50 of that of the B-52 bomber; after coating the absorbing material on the fairing of the 0H-6 and AH-1G Cobra helicopter engines The infrared radiation of the engine can be reduced by about 90%. In the 1990 Gulf War, the first F-117A aircraft that the United States entered Iraqi territory were stealth aircraft coated with absorbent materials. They effectively avoided Iraq’s radar monitoring. It is reported that the world's first stealth warship successfully developed by the Swedish Navy has been put into use. The United States, Britain, Japan, Russia and other countries have all developed their own stealth tanks and other stealth combat vehicles. In addition, electromagnetic wave absorbing materials can also be used to conceal landing lights and other airport navigation equipment and other ground equipment, ship masts, decks, submarine periscope brackets and air ducts and other equipment.
2. Improve the electromagnetic compatibility of the whole machine
The false signals generated by the reflection of electromagnetic waves by the aircraft fuselage may lead to false interception or false tracking of highly sensitive airborne radars; when several radars on an aircraft or a ship are working at the same time, the crosstalk between the radar transmitting and receiving antennas is sometimes very serious , The jammer on the plane or on the ship will also interfere with the radar or communication equipment that comes with it....... In order to reduce such interference, the excellent magnetic shielding of absorbing materials is commonly used abroad to improve the performance of radar or communication equipment. For example, coating absorbing materials on the fuselage of radar or communication equipment, antennas and all surrounding interferences can make them more sensitive and accurate to find enemy targets; coating absorbing materials on the surrounding walls of the opening of the radar parabolic antenna, It can reduce the side lobe's interference to the main lobe and increase the distance of the transmitting antenna, and it can reduce the interference of false target reflection on the receiving antenna; the application of absorbing materials in the satellite communication system will avoid the interference between communication lines and improve The sensitivity of the spaceborne communicator and the ground station, thereby improving the communication quality.
Three, RFID antenna anti-metal isolation application
This application mainly utilizes the high track rate characteristics of a type of high magnetic track rate, low loss type wave absorbing material; when in use, insert the wave absorbing plate between the 13.56MHz loop antenna and the metal substrate to increase the induced magnetic field through the wave absorbing material In itself, it reduces the chance of passing through the metal plate, thereby reducing the induced eddy current in the metal plate, thereby reducing the loss of the induced magnetic field. At the same time, because of the insertion of the absorber, the measured parasitic capacitance will also be reduced, and the frequency offset will be reduced. It is consistent with the resonant frequency of the card reader to improve the reading distance. Of course, the degree of improvement depends on the goodness of the characteristics of the absorbing material.
Four, safety protection
Due to the application of high-power radars, communication devices, microwave heating and other equipment, preventing electromagnetic radiation or leakage and protecting the health of operators is a new and complex topic, and absorbing materials can achieve this goal. In addition, there is a widespread problem of electromagnetic radiation in today's household appliances, which can be effectively suppressed through the rational use of absorbing materials and their components.
Five, microwave anechoic chamber
The space formed by the wall surface decorated by the absorber is called a microwave anechoic chamber. An equivalent non-reflective free space (no noise zone) can be formed in a dark room. The electromagnetic waves reflected from the surroundings are much smaller than the direct electromagnetic energy and can be ignored. Microwave anechoic chambers are mainly used for the measurement of characteristic impedance and coupling degree of radar or communication antennas, missiles, airplanes, spacecrafts, satellites, etc., the measurement of astronauts' shoulder antenna pattern, and the installation, testing and adjustment of spacecraft, etc. It can eliminate external clutter interference and improve measurement accuracy and efficiency (indoors can work around the clock), and it can also keep secrets.