Flexible Assembled Metamaterials for Infrared and Microwave Camouflage

Abstract

Light, heat, and waves in electromagnetic energy are the foundation for the advancement of human being. Camouflage materials based on metamaterials are used to excel the performance limits by manipulating the electromagnetic energy. However, multispectral camouflage materials with flexibility are difficult to fabricate because required radiative properties in each spectral regime are different and have largely different scales of the unit cell in a single structure. The authors propose flexible assembled metamaterials (FAM) by assembling the flexible infrared (IR) emitter and flexible microwave absorber. The authors adopt the intermediate layer to assemble the IR emitter and the microwave absorber, leading to securing the selective emission in IR wave measured by Fourier-transform infrared spectroscopy (FT-IR) measurement and broadening the wavelength of microwave absorption. They calculate the energy dissipation of accumulated energy due to the lowering the radiative energy in the IR regime similar to that of conventional camouflage materials. The wavelength having required absorption (>0.9) for microwave camouflage is wider 2-12 GHz than the conventional microwave absorber. FAM demonstrate multispectral camouflage performances through the decrease in the contrast radiant intensity for IR wave by 75% and the radar cross section for microwave by 99% compared to reference surfaces.