The compatible method of designing the transparent ultra-broadband radar absorber with low infrared emissivity

The multi-spectrum compatible design of electromagnetic (EM) waves has captivated great interest since metasurfaces emerge as a novel structure design method in researchers' eyesight. However, it is difficult to tailor the cross-spectrum performance simultaneously, which makes EM compatible design is still a challenging work. Here, we propose a design paradigm to endow the proposed metasurface with visible transparent, low infrared emissivity and microwave absorption. As a proof, the transparent materials indium tin oxide (ITO) films and polymethyl methacrylate (PMMA) are selected as the surface atom and substrate, respectively. To achieve the low infrared emissivity, the 6 omega/sq ITO film with a high duty cycle serves as the frequency selective surface (FSS) on the top layer. To obtain the absorption structure, the dimension of PMMA, distribution and sheet resistivity of the ITO film are searched by genetic algorithm (GA). As a result, both simulation and experiment show that the proposed metasurface realizes more than 76% visible transmittance, less than 0.24 infrared emissivity and over 90% absorption from 4 GHz to 18 GHz. Moreover, the most of PMMA between the FSS and absorption ITO has been hollowed out by laser cutting, which will make the top structure 90% lighter.

Automated summary

The compatibility of visible light transparency, low infrared emissivity, and microwave absorption in metasurface design is a challenging task. In this study, a design paradigm using transparent materials ITO and PMMA, with the optimization of dimensions and distribution through genetic algorithm, was proposed. The results showed that the designed metasurface achieved high visible transmittance, low infrared emissivity, and high microwave absorption within a specific frequency range.