Screen-printing high/low resistance using only a single silver nanowire ink: Resistance-gradient metasurface application for broadband microwave absorption and optical transparency

Transparent metasurface absorbers are highly sought after for their diverse applications, but achieving broad absorption bandwidths without sacrificing optical transparency remains a challenge. Traditionally, enhancing absorption involves increasing substrate thickness, which reduces transmittance. We address this by introducing a resistance-gradient metasurface (RGM) that combines broad absorption with high optical transparency. Unlike conventional methods requiring various inks for different resistances, our approach uses a single silver nanowire ink and screen-printing to create multiple resistances. This technique allows for flexible design and multiple resonances within the metasurface, achieving broad absorption even with a thin substrate. The RGM demonstrates an absorption bandwidth from 8.68 to 11.48 GHz with a substrate thickness of just 0.045 λ₀, and optical transmittance of 66.3 % at 550 nm. This innovation promises to enhance both substrate efficiency and bandwidth in transparent metasurface absorbers, broadening their application potential in advanced devices.