Fig. 1. The real parts (a) and imaginary parts (b) of the BDS perimittivity under different Fermi energies varying from 40 meV to 160 meV； the real parts (c) and imaginary parts (d) of the STO permittivitry under different temperatures increasing from 250 K to 400 K

Fig. 2. Schematic designs of the dual-tunable absorber model：（a） three-dimensional view；（b） two-dimensional top view；（c） two-dimensional side view

Fig. 3. The equivalent circuit model （ECM） of the proposed dual-tunable absorber

Fig. 4. (a) Simulated absorption, reflection, transmission of the designed absorber；(b) the comparison between the simulated and theoretical absorption spectrum

Fig. 5. The distributions of electric field at the frequency of 2.613 1 THz in the X-Y plane for （a） X-polarized wave；（b） Y-polarized wave

Fig. 6. (a) The comparison between the simulated absorption spectrum and the theoretical absorption spectrum analyzed by CMT；(b) the change laws of impedance of the proposed absorber under different frequencies

Fig. 7. Frequency dependence of absorptivity as (a) the BDS thickness increases；(b) the STO thickness increases；(c) the gold ground plane thickness increases

Fig. 8. Frequency dependence of absorptivity with (a) period；(b) polarization angle；(c) length of BDS rods

Fig. 9. (a) The change laws of absorption spectra under different Fermi energies of BDS；(b) the change laws of absorption spectra under different temperatures of STO