VO2 Thin Film as a Temperature Activated Electromagnetic Shield

This communication presents the fabrication, characterization and performance of a vanadium dioxide (VO2) thin film deposited on a c-cut sapphire substrate, and used as an electromagnetic screen whose shielding effectiveness is controlled through heating/cooling. The film is first deposited at high temperature on the substrate using a radiofrequency magnetron sputtering technique, and is then annealed in-situ in pure dioxygen atmosphere, to obtain the required oxide stoichiometry. The screen shielding effectiveness is measured using the nested reverberation chamber method at room temperature and at 75°C. At 65°C, VO2 undergoes an insulator to metal transition and the material conductivity drastically increases, resulting in a significant shielding effect of the VO2 layer at microwaves (2 – 34 GHz). The experimental results are in accordance with theoretical values predicted by an analytical model. The VO2- based electromagnetic shield is therefore a promising solution to protect sensitive electronics from high intensity radiated field by using the temperature rise as the trigger to rapidly improve the shielding effectiven