Highly Visible–NIR Transparent Metamaterial‐Window for Broadband Microwave Absorption and Shielding

Abstract Optically transparent metamaterial absorbers have unexceptionally encountered a great challenge in further improving optical transparency ranging from visible (Vis) to near‐infrared (NIR) and environmental applicability, due to the limitations of constituent materials and multilayer structures. To overcome this limitation, a highly Vis‐NIR transparent metamaterial‐window with outstanding microwave broadband absorption and practical durability is proposed in this paper, which adopts a typical sandwich structure consisting of a cross‐ and cross‐ring‐shaped resonator and a reflective backplane, separated by a quartz glass. Experimental results indicate that the proposed metamaterial‐window achieves >80% absorptivity, covering a wide frequency range of 6.6–13.8 GHz with a relative bandwidth of 70.59%, while the measured shielding effectiveness is >16.94 dB, at 4.0–16.0 GHz. In addition, the corresponding physical mechanism is revealed by exploiting a classical multiple reflections interference model. More significantly, both the patterned resonator and backplane layers are formed by microscale gold meshes with high Vis‐NIR transmittance and environmental resistance, thereby enabling excellent salt spray corrosion resistance and high‐temperature stability, as well as an average optical transmittance of ≈87.35% at 400–1 800 nm. These advantages endow the design a promising candidate for addressing anti‐electromagnetic interference and electromagnetic shielding both in military and civilian.