Fig. 4: Schematic diagram of the experiments and experimental results.
a The schematic of the dual static experiment for S21. The metasurface or the metal plate is placed on the turntable, and the two horns are used to obtain S21. b The illustration of the blind area between two horns due to the support arms. c The schematic of the single static experiment for S11. The metasurface or the metal plate is placed on the turntable, and the single horn is used to obtain S11. d The illustration of the traveling standing wave resulting from the highly efficient retroreflection. The schematics of the measurement of the abnormal-harmonic reflection (e), dual-beam splitting (i), and three-channel retroreflection (m). The photos of the actual experimental scenes (f the abnormal-harmonic reflection, j dual-beam splitting, and n three-channel retroreflection). The fabricated metasurfaces for the abnormal-harmonic reflection (g), dual-beam splitting (k), and three-channel retroreflection (o). h The comparison of results for the abnormal harmonics reflection (solid lines represent theoretical results, and the circle, square, and triangle represent experimental results). l The comparing results for the beam splitter (solid lines represent theoretical results, and the triangle represents experimental results). p The comparing results for the three-channel retroreflector (solid lines represent theoretical results, dashed lines represent simulation results, and the triangle represents experimental results). In retroreflection, the energy distributions of different spatial harmonics under d −39°, e 39°, and f 0° incidence, respectively. The results of the far-field radiation under q −39°, r 39°, and s 0° incidence, and the inserts represent the energy distributions of different spatial harmonics (0th, −1st, −2nd), respectively
