Low-frequency Microwave Absorption of CIPs@Mn_0.8Zn_0.2Fe₂O₄-CNTs Composites

Development of 5 G wireless communication and low-frequency radar detection has made low- frequency electromagnetic wave radiation a serious problem today. Although research on medium and high frequency band absorbing materials is now relatively mature, designing low frequency band absorbing materials remains a major challenge. Here, we designed a low-band composite absorbing material of 0.5-3 GHz based on the quarter-wavelength cancellation mechanism. A CIPs@Mn0.8Zn0.2Fe2O4-CNTs ternary composites were prepared by using a simple one-step hydrothermal method, which involved growing ferrite on the surface of carbonyl iron powder and carbon nanotubes. The influence of carbon nanotube content on the absorption peak frequency of the material was investigated. Experimental results show that carbon nanotubes enhances the material's attenuation coefficient by introducing additional interfacial polarization, dipole polarization and other loss mechanisms. Furthermore, coupling of high dielectric and high permeability enables the material to achieve better impedance matching in the low frequency band based on the quarter-wavelength cancellation mechanism. At a thickness of 4 mm, the reflection loss of the samples was obtained at 2.11 GHz and 1.75 GHz, with a -10 dB bandwidth of 1.70-2.70 GHz and 1.40-2.20 GHz, respectively. The composites exhibit excellent low-frequency absorption performance, endowing it highly suitable for applications helped by its simple preparation process and well low-frequency absorption. This research provides a new method for developing more effective low-frequency absorbing materials.