Ultrathin multifunctional carbon/glass fiber reinforced lossy lattice metastructure for integrated design of broadband microwave absorption and effective load bearing

Microwave absorbers as an effective way to reduce microwave radiation in stealth technologies and electromagnetic compatibility have attracted great attentions recently. Herein, a novel multifunctional carbon fiber (CF)/glass fiber (GF) reinforced lossy lattice metastructure for broadband microwave absorption and effective load bearing is proposed for the first time based on the structural similarity of photonic crystal and lightweight mechanical lattice. The lossy lattice is fabricated with nano lossy composite composed of multiwall carbon nanotube (MWCNT) and spherical carbonyl iron (CI) particles to manipulate complex permittivity and complex permeability. Sub-wavelength effect and structural optimization are applied for the metastructure to extend −10 dB absorption bandwidth from 3.42 GHz to 19.73 GHz with thickness of 3.5 mm. With solid attachment of CF and GF, the metastructure achieves high average equivalent strength of 167.35 MPa and fracture strain of 5.45%. A long plastic stage of the metastructure is observed after GF fracture or GF delamination in three-point flexural test. The integrated design of microwave absorbing and mechanical properties make it promising for practical applications in mass production.