Ultra-wideband metasurface absorber based on ITO material

At present, transparent conductive materials have been widely used in high-performance electromagnetic absorbers, especially the transparent conductive oxide indium tin oxide (ITO). This paper designs and studies an ultra-wideband transparent absorber based on the ITO material. This absorber adopts a multi-layer structure of four layers of the ITO conductive film and three layers of the polyvinyl chloride dielectric material, achieving over 90% efficient absorption in the 2–18 GHz frequency band, covering the four key electromagnetic wave segments, S, C, X, and Ku, with a relative absorption bandwidth as high as 156.4%. This structure not only possesses ultra-wideband absorption characteristics but also demonstrates wide incident angle stability, polarization insensitivity, and excellent flexible transparency. Through the comparative analysis of numerical simulation and experimental tests, the rationality and feasibility of the design were verified. Compared with the existing transparent wideband absorbers, this design shows significant advantages in the low-frequency band (especially in the radar band of 2.5–18 GHz), while featuring a thinner thickness and higher optical transparency. This innovative design provides a new technical path for the development of a new generation of stealth skin technology and intelligent electromagnetic shielding windows, especially demonstrating a significant technical potential in weight-sensitive application scenarios such as unmanned aerial vehicles.