Organic UWB metamaterial absorber with angle insensitive based on flexible frequency selective surface

An organic metamaterial absorber (OMA) with a total thickness of 2.98 mm composed by multi-layer flexible frequency selective surface (FSS) and worked in ultra wideband (UWB) is investigated. The proposed absorber is stacked on a metal substrate by organic materials layer by layer, such as polyimide and polyvinyl chloride. According to equivalent circuit and electromagnetic field analysis, periodic FSS patterns are printed on organic materials using organic conductive ink. The absorption rate of the structure is high up to 90 % and the fractional bandwidth (FBW) reached 147.7 % at 11.78–78.32 GHz, which shows incident angle insensitive within 50°. In addition, the fabricated prototype with a single unit cell of 0.17 g is measured in an anechoic chamber using free space method. Furthermore, the measurement is in great agreement with the simulation, which demonstrates the reliability and the practical application prospect of the provided OMA with flexible, lightweight and ultrathin construction.