Infrared/radar stealthy metasurface design method based on the equivalent circuit model

In this paper, the mapping relationship between circuit components and metal patches on metasurfaces is investigated from the equivalent circuit model, and a method for designing metasurfaces based on equivalent circuits is proposed. Metasurfaces have a wide range of applications in electromagnetic absorption and polarization conversion, etc. However, the development progress of metasurfaces has lagged behind because of the inefficiency of full-wave simulation and unclear mechanism. Circuit simulation, thanks to the integration of momentum functions, has a great advantage over full-wave simulation in terms of time and efficiency; at the same time, it is easy to adjust the direction of improvement due to its clear mechanism. Experiments have proved that the method of metasurface design based on equivalent circuit is accurate, fast, and effective. Based on this method, a double-layer metasurface with infrared/radar stealth performance is designed using indium tin oxide/polyethylene terephthalate conductive film as the impedance-matching layer material and polyvinyl chloride as the dielectric layer material. The metasurface is characterized by transparency and flexibility and is experimentally proved to have an absorption bandwidth of 7.7–18 GHz and a relative bandwidth of 80.16%. The double-layer metasurface can isolate electromagnetic waves in the infrared band through infrared thermography test, realizing the radar wave-absorbing function with infrared stealth effect at the same time.