Fig. 1. Schematic diagram of terahertz phase shifter
(a): Three-dimensional diagram; (b): Two-dimensional diagram of the bottom silicon grating; (c): Terahertz wave transmission model in the terahertz phase shifter

Fig. 2. Terahertz waves diffraction efficiency under different grating constants

Fig. 3. Terahertz diffraction intensity at different grating constants
(a): d=60 μm; (b): d=61 μm; (c): d=62 μm; (d): d=63 μm; (e): d=64 μm; (f): d=65μm

Fig. 4. Diffraction efficiency of terahertz waves through phase shifter for different liquid crystal materials with dielectric constant ε_⊥=2.47 (without applied electric field) and ε_//=3.26 (with applied electric field)

Fig. 5. Terahertz wave diffraction intensity at different dielectric constants of liquid crystal materials
(a): ε_⊥=2.47; (b): ε_//=3.26

Fig. 6. Phase curves of terahertz waves phase shifter under different dielectric constants of liquid crystal

Fig. 7. Phase curve of terahertz wave transmission through the phase shifter
(a): Single frequency point curve at different incident angles; (b): Single frequency point curve under TE and TM polarization

Fig. 8. Terahertz wave phase shifter loss curve
(a): Return loss; (b): Insertion loss