Absorbing materials and their applications

Introduction: In the rapid development of modern technology, stealth technology is undoubtedly one of the shining pearls. One of the secret weapons to achieve invisibility is absorbing materials. This magical material can absorb or scatter radar waves through its special electromagnetic properties, thereby reducing the likelihood of objects being detected. This article will take you in depth to explore the mysteries of absorbing materials and their widespread applications in various fields. What is an absorbing material? Absorbing materials refer to a type of material that can effectively attenuate the energy of incident electromagnetic waves. It achieves this effect through three basic mechanisms: resistance loss, hysteresis loss, and structural resonance. Resistance loss refers to the energy consumed by the resistance of a conductor when electromagnetic waves pass through it; Hysteresis loss is the dissipation of electromagnetic wave energy by utilizing the heat generated by the flipping of magnetic domains inside materials such as ferrite; Structural resonance refers to the resonance effect that occurs within a material’s internal structure at a specific frequency, resulting in efficient absorption of electromagnetic waves. The classification of absorbing materials can be divided into the following categories based on different absorption mechanisms and composition: 1 Conductive coatings and composite materials: These materials usually contain substances with good conductivity such as carbon nanotubes, graphene, metal powders, etc., which can absorb electromagnetic waves through resistance loss. 2. Ferrite material: Ferrite is a typical soft magnetic material, and its internal magnetic domain switching is accompanied by energy loss, making it suitable for manufacturing absorbing materials. 3. Porous materials: such as foamed plastics, honeycomb structures, etc. There are a large number of small air gaps distributed inside them, which have a strong reflection effect on electromagnetic waves, so as to achieve the effect of absorbing waves. 4. Metamaterials: This is an artificially designed material that endows the material with new electromagnetic properties, including negative refractive index, zero reflection, etc., through specific geometric structures and arrangements, thereby achieving efficient band control and wavefront manipulation. The preparation and optimization of absorbing materials depend not only on their composition materials, but also closely related to their microstructure. In order to achieve the best absorption effect, it is necessary to prepare absorbing materials through reasonable formula design, advanced processing technology, and precise control measures. At the same time, it is necessary to continuously test and optimize its performance. The application fields of absorbing materials are very extensive, covering multiple aspects such as military, communication, and electronic engineering. The following are some main application scenarios: 1 Military stealth: Absorbing coatings are widely used in stealth coatings for aircraft, ships, etc. to reduce their visibility on radar and improve battlefield survival capabilities. 2. Antenna cover: The antenna cover made of absorbing material can effectively shield the interference of the surrounding environment and protect the normal operation of the antenna without affecting signal reception. 3. Electromagnetic Compatibility (EMC): In high-frequency electronic devices, the use of absorbing materials can prevent electromagnetic radiation from interfering with other devices and ensure the stable operation of the system. 4. Anti reconnaissance: In fields such as satellite communication and mobile communication, absorbing materials can help conceal the location of ground facilities and prevent enemy reconnaissance. 5. Wireless charging: Through reasonable design, absorbing materials can also improve the efficiency of wireless charging and reduce the impact of electromagnetic field leakage on the outside world. With the continuous advancement of technology, the research and application prospects of new absorbing materials are broad. For example, intelligent responsive absorbing materials can automatically adjust their electromagnetic characteristics according to environmental changes, further improving stealth effects; In addition, research on absorption in the terahertz band is gradually being carried out, which will help solve the application difficulties of existing absorption materials at higher frequencies. Conclusion: As a key component of stealth technology and electromagnetic compatibility, absorbing materials will continue to play an important role in the future. With the increasing concern for information security, national defense needs, and personal privacy, we believe that the research and development of absorbing materials will deepen, bringing more surprises and convenience to our lives. Reference: [1] Yang, Y. M.,& Zhang, W. (2018) A review of electrical wave absorbers: Mechanisms and materials Journal of Advanced Ceramics, 7 (3), 269-298. [2] Li, J., Liu, X., Wang, Z. L.,& Cui, T. J. (2018) Metamaterials for electrical waves: Modulating the promotion of electrical waves with metasurfaces National Science Review, 5 (3), 370-392. [3] Gong, S.,& Cai, B. (2019) Progress in radar cross section reduction technology using frequency selective surfaces IEEE Access, 7, 118318-118332