Microwave absorbing composite lattice grids

Stretching dominated lattice grids reinforced by glass fibers and carbon fibers filled with spongy materials were designed and manufactured to achieve multifunctional structures with microwave absorbing abilities. The reflectivity of the GFRC and CFRC grid panels was measured in the darkroom at normal and oblique incidences, respectively. GFRC grid panels of 20 mm thickness and CFRC panels of 18 mm thickness displayed excellent microwave absorbing abilities in the range from 4 GHz to 18 GHz. The reflectivity of the grid panels is poorer than that of the foam panels in the range from 4 GHz to 10 GHz, but is better in the range from 10 GHz to 18 GHz. That difference in the reflectivity enhancement is explained by the grating lobe mechanism. The studies show that the composite grid panels are structural absorbent with weight efficiency.