This letter presents a thermal-switchable absorbing metasurface (TSAM) based on the phase-change material vanadium dioxide (VO₂). A thin film of VO₂ was deposited on a sapphire substrate by a magnetron sputtering and then sliced into tiny chips, which can be regarded as thermal-switchable resistors. The surface structure of the thermal-switchable absorbing metasurface element is realized by loading four VO₂ chips into a square metallic loop. Polytetrafluoroethylene (PTFE) is used as the substrate due to its high thermal conductivity compared with foam. The TSAM is on “absorbing” mode when it is heated underneath, and is switched into “reflecting” mode at room temperature. The absorbing mode is characterized by a wideband absorption (8 - 22 GHz). A TSAM prototype was fabricated and measured to verify this design.

This article presents a thermal-switchable metamaterial absorber (TSMA) based on the phase-change material of vanadium dioxide (VO₂). VO₂ thin film was deposited on sapphire substrate by magnetron sputtering followed by vacuum annealing treatment. Then, the prepared VO₂ film was sliced into tiny chips for thermal-switchable elements. The surface structure of TSMA was realized by loading four VO₂ chips into a square metallic loop. The absorption frequency of TSMA was located at 7.3 GHz at room temperature and switched to 6.8 GHz when the temperature was heated above the critical phase transition temperature of VO₂. A VO₂-based TSMA prototype was fabricated and measured to verify this design. The design is expected to be used in metasurface antennas, sensors, detectors, etc.