A transparent water-based metamaterial broadband absorber with a tunable absorption band

Abstract

In this study, a tunable and optically transparent water-based wideband metamaterial absorber (MMA) is proposed and verified. By adjusting the thickness of the water layer, the conversion of the absorber absorption band from 7.4-22.4 GHz to 23.1-35.5 GHz can be achieved, which demonstrates the flexibility of MMA. Indium tin oxide (ITO) as the resonant and reflective layers of the material structure. Optically transparent polymethyl methacrylate (PMMA) is used as a medium container to encapsulate the water. Furthermore, the suggested MMA is polarization insensitive and has broad incident angle stability. Experiments verify the excellent properties of the proposed MMA. As a result, the suggested MMA has various applications in military and medical equipment optical windows.

Visible–Infrared Transparent Ultra-Thin Frequency-Tunable Microwave Absorber Based on a Nanometer-Thick Patterned VO2 Film

“…In addition, based on the small duty cycle of the patterned VO 2 film and the metallic mesh, FTMAPV can achieve optical transparency in the visible–infrared band. Compared with the previously reported transparent tunable absorbers, ,,,, our designed FTMAPV has the thinnest relative thickness and the widest optical transparency wavelength range. The proposed absorber prototype is a viable solution for ultra-thin frequency-tunable microwave absorbers with broadband optical transparency and has numerous potential applications in optical and intelligent fields.…”

“…In addition, our absorber has excellent amplitude modulation depth and frequency modulation range. Although the water-based tunable broadband absorber in ref has a wider frequency modulation range, this absorber is three times thicker than our FTMAPV, and the existence of water renders it unsuitable for numerous applications.…”

Low-profile reconfigurable saline water-based ultrawideband metamaterial absorber

“…In 2020, an EM absorber made from polylactic acid (PLA) with swastika-shaped units was created using 3D printing technology, showing a high absorption rate of over 90% across frequencies ranging from 9.3 to 49 GHz [27]. In the study by Yao et al [28], a tunable water-based metamaterial absorber was presented with a classical sandwich-type structure. Interestingly, this absorber can switch between two different absorption bands, 7.4-22.4 GHz and 23.1-35.5 GHz, by injecting or extracting the water layer.…”

A reconfigurable ultra-broadband transparent absorber combined with ITO and structural water

“…29 Yao et al proposed a tunable optically transparent water-based broadband metamaterial absorber, which can be adjusted by the thickness of the water layer to realize the conversion of the absorption band from 7.4-22.4 GHz to 23.1-35.5 GHz. 30 In this paper, we present an ultra-broadband transparent absorber consisting of a double-layer of complementary ITO resonant patterns, PMMA, and a structured water substrate with tunable microwave absorption and high optical transparency. The mutually non-overlapping multi-layer stacked structure produces stable resonance while maintaining high optical transparency.…”

“…29 Yao et al proposed a tunable optically transparent water-based broadband metamaterial absorber, which can be adjusted by the thickness of the water layer to realize the conversion of the absorption band from 7.4–22.4 GHz to 23.1–35.5 GHz. 30…”