Fig. 1. (a) The integration model of an AlGaN/GaN terahertz detector and a metasurface lens; (b) Schematic diagram of phase regulation of metasurface element array; (c) Schematic diagram of terahertz antenna structure

Fig. 2. (a) and (c) show the schematic diagram of single-sided cell structure and its energy distribution; (b) and (d) show the schematic diagram of double-sided cell structure and its energy distribution

Fig. 3. The phase and transmittance curves of the single and double structure of metasurface lens vary with diameter

Fig. 4. The two-dimensional phase distribution of metasurface lens

Fig. 5. (a) The array of single-sided metasurface lens; (b) The array of double-sided metasurface lens

Fig. 6. (a) and (c) show the field intensity distribution on the y-z plane and one-dimensional distribution on the y=0 of a single-sided structure when x =0 ; (b) and (d) are the field intensity distribution on the y-z surface when x=0 and one-dimensional distribution when y=0 of the double-sided metasurface lens; (e) and (g) are the field intensity distribution on the x-y plane and the one-dimensional distribution on y=0 when z=1.026 mm of the single-sided metasurface lens; (f) and (h) are the field intensity distribution on the x-y plane and the one-dimensional distribution on y=0 when z=1.067 mm of the double-sided metasurface lens

Fig. 7. Dispersion characteristics of double-sided metasurface lens

Table 1. The detail parameters of unit structure

Table 2. Design parameters of metasurface lens

Table 3. Performance comparison of metasurface lens in terahertz band