Double-layer stepped metamaterial with broadband and wide-angle electromagnetic wave absorbing performance based on uniform epoxy composite plate from layer-by-layer gel/integrated solidification process

As the frequency range and application scenarios of electromagnetic devices continue to expand and diversify, developing materials with both broad frequency response and excellent wide-angle absorbing performance has become increasingly important. However, research on the mechanisms and strategies for enhancing the wide-angle absorption performance of all-dielectric metamaterials is still limited. Furthermore, stable absorbing plate materials with consistent structural and electromagnetic properties are essential for metamaterial design. The commonly used functional particles often experience uncontrollable sedimentation, leading to significant and irregular changes in the structure and electromagnetic characteristics of composite materials. In this work, a layer-by-layer gel/integrated solidification (LG/IS) process is proposed, enabling the fabrication of a uniform composite plate. Based on this plate, a double-layer stepped metamaterial (DSMM) with cubic copper cores (CCC) embedded in each unit cell is designed and manufactured. The introduction of CCCs strengthens the internal electromagnetic field through mechanisms such as electromagnetic resonance and unit coupling, improving impedance matching and extending the absorption bandwidth to 11.20 GHz, a 10.89 % increase compared to ordinary DSMM. Additionally, embedding CCCs stabilizes the electromagnetic field at large incident angles, significantly enhancing wide-angle absorption performance. This work provides valuable theoretical guidance and technical support for the bandwidth expansion and optimization of wide-angle absorption in all-dielectric metamaterials.