Broadband radar-absorbing performance of square-hole structure

To broaden the absorbing frequency band of radar-absorbing material (RAM), a simple radar-absorbing structure (RAS) with square pore was designed and prepared by 3D printing and coating dipping methods to verify the reliability of the design in this paper. On this basis, the gradient optimization design of sheet resistance of the structure was carried out to investigate the effect of gradient sheet resistance on the radar-absorbing performance. The results show that the sheet resistance and wall thickness of the structure have significant influence on the reflection loss peak and the absorbing bandwidth. When the side length L = 15 mm, the sheet resistance R = 500 Ω/sq, the height H = 20 mm, and the wall thickness w = 1.0 mm, the effective radar-absorbing bandwidth with a reflection loss below −10 dB can reach 15.82 GHz in the frequency band of 1–18 GHz. After the gradient optimization design of sheet resistance, the radar-absorbing bandwidth is wider and the absorbing curve is flatter, the gradient design of sheet resistance with appropriate tolerance can further improve the radar-absorbing performance of broadband. This RAS provided a new technical way for the development of “thin, light, wide, and strong” RAMs. (1) The schematic diagram and equivalent circuit model of square-hole structure; (2) The simulation and test results of the square-hole structure