A low-RCS coding metasurface utilizing 3-D printed ABS shells and carbonyl iron powder/polyimide composite patches via hybrid mechanisms

Based on three-dimensional (3-D) printed acrylonitrile butadiene styrene (ABS) shells and carbonyl iron powder/polyimide (CIP/PI) composite patches, a low-profile and low-radar cross section (RCS) coding metasurface is proposed through the utilization of the hybrid mechanisms of energy absorption and scattering control. By adjusting the geometric parameters of the ABS shells and CIP/PI composite patches, diverse absorptive coding unit cells are designed. The arrangement of these absorptive unit cells is optimized through a genetic algorithm (GA), and the optimal backscattering reduction of the low-RCS metasurface is attained. The ratio of energy dissipation of the proposed metasurfaces clearly explains the effect of absorption and scattering on the RCS reduction. The results from theoretical calculations, full-wave simulations, and experimental measurements are in good agreement. The final experimental results demonstrate that the optimal coding metasurface achieves an RCS reduction exceeding the 10- dB level in the frequency range of 2.22 to 18 GHz, with a thickness of only 7 mm. Therefore, our proposal demonstrates considerable potential for engineering applications in platforms characterized by low-RCS properties.