A hybrid metamaterial with broadband radar cross section reduction and low infrared emissivity for multispectral stealth

Metamaterials exhibiting exotic electromagnetic properties present new opportunities for countering multi-spectrum detection technologies. In this paper, a hybrid metamaterial with broadband radar cross section reduction (RCS) and low infrared (IR) emissivity for multispectral stealth was proposed. This hybrid metamaterial consists of a two-dimensional random array of two hybrid meta-atoms, which include a magnetic absorbing material layer, resistive metasurfaces, dielectric foams, and an infrared stealth layer (IRSL). Such hybrid meta-atoms are designed to be lossy and possess a specific reflection phase difference, enabling the proposed metamaterial to integrate absorption and phase cancelation mechanisms for broadband RCS reduction. The IRSL consists of periodically arranged high-filling-ratio indium tin oxide patches that exhibit high reflectivity to IR waves while allowing high transmittance to microwaves. Based on the equivalent circuit model, we parametrically modeled the hybrid metamaterial and introduced the genetic algorithms for optimization. Ultimately, the optimized hybrid metamaterial achieves an RCS reduction greater than 10 dB from 2.15 to 18 GHz and an IR emissivity of less than 0.2 in 3–14 μm IR band, with a total thickness of 6 mm. The concept and specific design presented in this paper are promising in the realization and application of multispectral stealth materials.