Vertically incident light reflecting thermal emitters using metal-dielectric-vanadium dioxide thermochromic metamaterials

<p dir="ltr">A thermal radiator with smart VO2-based metamaterials is investigated that passively adjusts its radiative properties as a function of temperature. At high temperatures, the proposed device exhibits low absorption at the vertical angles but high emission at high angles, facilitating effective heat dissipation even under solar irradiance, while at low temperatures it acts as a low-emitting material. It can be applied to a radiator used in spacecraft. The device property is experimentally demonstrated by measuring the reflectance at different temperatures and angles. The results demonstrate that the temperature change caused by the difference in solar illumination is reduced from 210.6°C for blackbody radiators to 120.8°C, even while maintaining a similar maximum temperature level when exposed to full sunlight.</p>