Electromagnetic functionalization of mechanical lattice to metastructure with oblique incident broadband microwave absorption

Electromagnetic functionalization of mechanical lattice is an important method to integrate mechanical and electromagnetic properties into one structure with effective load bearing and broadband microwave absorption. Herein, the gradient lattice metastructure (GLM) is fabricated by dielectric-magnetic lossy nano composite strengthened by carbon fiber and glass fiber reinforced polymer. A large mutation genetic algorithm is developed to optimize the GLM with fine convergence property. Several large mutation modules are incorporated into the program to speed up the optimization process and improve global convergence. The measured −10 dB absorption bandwidth covers 2–5 GHz and 6.5–17.3 GHz while −9.5 dB absorption bandwidth covers 2–17.3 GHz. The oblique incident broadband absorption is achieved from normal incidence to the grazing incidence of 85° in traverse electrical (TE) and traverse magnetic (TM) polarization. Gradient lattice design is effective to overcome systemic oblique incident absorption deterioration originating from enhanced tangential electric field intensity in large incident angles. The nominal tensile strength of GLM reaches 108.4 MPa with maximum flexural load of 1.83 kN. The high electromagnetic and mechanical properties are achieved simultaneously by electromagnetic functionalization of mechanical lattice.