Synergistic Effect of Multi-dimensional Magnetic Intrinsic Absorption and Porous Structure Scattering for Efficient Microwave Absorption

Wireless communication technology permeates modern society, with low-frequency bands such as the C-band (4–6 GHz) serving as primary operational frequencies. The potential environmental impact of microwave radiation from these bands has garnered significant attention. However, the longer wavelengths characteristic of low-frequency signals necessitate larger absorber dimensions, presenting a critical challenge for developing lightweight microwave absorption materials. Herein, the design idea of synergizing the intrinsic absorption of multi-dimensional magnetic powder and the scattering mechanism of microporous structure was proposed. Lightweight porous polyurethane (PU) composites co-modified by the flaky carbonyl iron (FCI)/spherical carbonyl iron (SCI) were successfully obtained by a one-step foaming method. The FCI/SCI/PU achieved a minimum reflection loss per unit density of − 44 dB·cm 3 /g. This composite foam material shows advantages of easy preparation, low cost, and excellent low-frequency absorption performance, which has a great application prospect in creating an electromagnetic clean and safe environment. Meanwhile, this coordinated design strategy of magnetic constituents and microporous structures provides a reference for the development of low-frequency microwave absorption materials.