Optical Transparent Ultrabroadband Metamaterial Absorber With Matching Layer and Gradient Impedance

The optical transparent metamaterial absorber (MA) still faces challenges such as narrow bandwidth, large thickness, and poor low-frequency absorption. In this work, we proposed an MA composed of three layers of transparent resin glass deposited with indium tin oxide (ITO). By adding a matching layer and a dual-periodic pattern, the impedance matching both internally and externally of the absorber is effectively improved, enabling ultra-wideband absorption while reducing thickness. Simulation and measurement results indicate that the absorber can achieve reflectivity below -10dB from 2.91 to 18 GHz with an overall thickness of 11mm, resulting in an absorption bandwidth of 144.3% and figure-of-merit (FoM) of 13.527. Additionally, it exhibits optical transparency, stability under oblique incidence, and miniaturization. The proposed MA holds potential applications across multiple fields and provides innovative insights for the design of high-performance absorbing materials.