Radar Infrared‐Compatible Camouflage Performance of High‐Entropy Alloy Coating Enhanced by Double‐Layer Hexagonal Metasurface

Abstract

Recently, high‐entropy alloy (HEA) microwave‐absorbing materials have attracted extensive attention. Herein, a double‐layer structure consists of a low‐infrared emission metasurface and a FeCoNiMn0.5Si0.5Al0.5 HEA coating with enhanced microwave absorption performance is designed. The upper metasurface consisting of periodic hexagonal aluminum structural unit has excellent low‐infrared emission properties, while enabling selective transmission and absorption enhancement of radar waves. The emissivity of the low‐infrared emitting layer is lower than 0.2, and the metastructure on its surface affects more on the high‐frequency absorption performance. The bottom layer made of HEA coating with 1 mm hexagonal etching structure has an effective absorption bandwidth of 2.8 GHz, and its reflection loss (RL) can reach −42 dB. There is a certain fit relationship between the unit size of the periodic structure and the absorption performance of the underlying coating. For the coatings with high‐frequency RL peaks, a larger unit size of the periodic structure will lead to an obvious improvement on the absorption performance. A broad application prospect for multiband compatibility stealth is provided.