Study on frequency selective/absorption/reflection multilayer composite flexible electromagnetic wave absorbing fabric

In order to realize wide-band, high-efficiency and flexible electromagnetic wave absorption, an effective method is the combination of different electromagnetic functional materials. How to use and make the multilayer materials with individual absorption, reflection and selective transmission characteristics is very important. In this work, multilayer composite flexible absorbing fabrics made of a frequency selective surface (FSS), carbonyl iron coated fabrics (CIFs) and copper-nickel plated conductive woven fabrics (CWFs) were prepared. The layered composite materials have a thin thickness, good flexibility and adjustable absorption band, which provide a reference for the development of lightweight and efficient electromagnetic wave absorbing materials. The influence of the resonance point, wave absorbent content and conductive layer on the absorbing properties were studied. CIF-3 with a surface density of 2046.9 g/m ² has the best absorption performance with a minimum reflectivity of –20.52 dB at 12.56 GHz. A one-layer FSS can broaden the absorption bandwidth; the broadening degree varies with the resonance point of the FSS, which also makes the absorption band adjustable. The bandwidth of f ₁₂ /CIF-3 with reflectivity of less than –10 dB can reach 5.68 GHz. Besides, CWF is beneficial to increase the absorption intensity, and the best reflectivity of CIF-3/CWF can reach –27.73 dB. Furthermore, three-layer composites can improve the absorption strength and bandwidth of CIF at low frequency. Compared with CIF-3, the reflectivity of f ₁₄ /CIF-3/CWF decreases 8.06 dB at 11.28 GHz, and the bandwidth is 4.72 GHz, which widens by 0.32 GHz.