Fig. 2. Mm-wave dielectric properties of the VO₂ nanolayer at low input power and increasing temperature.

(A) Mm-wave transmittance T, reflectance R, and absorptance A of the VO₂-on-sapphire wafer at 95-GHz input power of ≤10 mW and successively increasing temperature θ. (B) Temperature-dependent real (ϵ′_VO2) and imaginary (ϵ ′′_VO2) parts of the relative permittivity of the VO₂ layer at 95 GHz, determined from the measurements of the insertion loss and phase of the VO₂-on-sapphire wafer (solid lines) and transmittance measurements of the photonic limiter (dashed lines).