Design of highly reflective film for smart radiation device

Smart radiation device (SRD) based on the asymmetrical Fabry-Perot cavity automatically tune its IR emittance depending on the ambient temperature, making it an ideal choice for thermal control system of spacecrafts. The low solar absorption is desirable for SRD to prevent the spacecraft from overheating by sun light. In this paper, a multilayer highly reflective film with (LH)k stacking layers is designed to reduce the solar absorptance (As) of the Ag/Al₂O₃/VO₂ structured SRD. The reflective film achieves a high reflection band in ~220 nm bandwidth from 460 nm to 680 nm, which results in a reduction of the solar absorptance by 25.56 % for SRD working at low temperature and 24.27 % at high temperature as the stacking factor k = 5. The simulation results indicate that an economic reflective film with k = 3 can achieve effective suppression of As of SRD, demonstrating the promising potential of the proposed reflective film in thermal control application of spacecrafts.