Fig. 1. Schematic mechanism of the AIHM for the holographic image.

Fig. 2. Holographic images including Arabic numbers of “1,” “2,” “3” and alphabet letters of “A,” “B,” “C.”

Fig. 3. Geometrical structure of this proposed meta-atom and corresponding propagation characteristic. (a) Geometric modeling for meta-atom simulation. (b) Maximum equivalent impedance for different gap sizes between adjacent meta-atoms. (c), (d) Equivalent impedance for surface wave propagation direction θk, on the interface with fixed gap ga=0.3  mm, θs=30°, 120°, respectively, at a frequency of 21 GHz.

Fig. 4. Tensor impedance components distributed on different positions. (a) and (d) Arabic numerals “1.” (b) and (e) Arabic numerals “2,” (c) and (f) Arabic numerals “3.”

Fig. 5. Tensor impedance components of position function. (a) and (d) Capital letters “A.” (b) and (e) Capital letters “B.” (c) and (f) Capital letters “C.”

Fig. 6. Geometrical parameters at different positions. (a) and (d) Arabic numerals “1.” (b) and (e) Arabic numerals “2.” (c) and (f) Arabic numerals “3.”

Fig. 7. Geometrical parameters of position function. (a) and (d) Capital letters “A.” (b) and (e) Capital letters “B.” (c) and (f) Capital letters “C.”

Fig. 8. Simulated near-field holographic images of Arabic numerals “1,” “2,” “3” distributed on the plane 38 mm away from the developed AIHM working at (a), (f), (k) 18 GHz, (b), (g), (l) 19 GHz, (c), (h), (m) 20 GHz, (d), (i), (n) 21 GHz, and (e), (j), (o) 22 GHz.

Fig. 9. Simulated near-field holographic images of capital letters “A,” “B,” “C” distributed on the plane 38 mm away from the developed AIHM working at (a), (f), (k) 18 GHz, (b), (g), (l) 19 GHz, (c), (h), (m) 20 GHz, (d), (i), (n) 21 GHz, and (e), (j), (o) 22 GHz.

Fig. 10. Tensor impedance components of position function for different radiation angles of (a) and (e) (θs=0°,φs=0°), (b) and (f) (θs=10°,φs=0°), (c) and (g) (θs=−15°,φs=0°), (d) and (h) (θs=20°,φs=0°) operating at 21 GHz.

Fig. 11. Geometrical parameters of position function for different radiation angles of (a) and (e) (θs=0°,φs=0°), (b) and (f) (θs=10°,φs=0°), (c) and (g) (θs=−15°,φs=0°), (d) and (h) (θs=20°,φs=0°) operating at 21 GHz.

Fig. 12. Simulated near-field holographic images of capital letters “B” distributed on the plane 80 mm away from the developed AIHM with different radiation angles operating from 18 GHz to 22 GHz.

Fig. 13. Prototype of our designed AIHMs for holographic images of (a) Arabic numerals “1,” (b) Arabic numerals “2,” (c) Arabic numerals “3,” (d) capital letters “A,” (e) capital letters “B,” (f) capital letters “C,” (g) capital letters “B” with radiation angle of (θs=0°,φs=0°), (h) capital letters “B” with radiation angle of (θs=10°,φs=0°), (i) capital letters “B” with radiation angle of (θs=−15°,φs=0°), (j) capital letters “B” with radiation angle of (θs=20°,φs=0°).

Fig. 14. Environment of near-field measurement in microwave anechoic chamber for (a) broadside holographic imaging and (b) tilt radiation hologram.

Fig. 15. Measured reflection coefficient of the developed metasurface for (a) broadside holographic imaging and (b) tilt radiation hologram.

Fig. 16. Measured near-field holographic images of Arabic numerals “1,” “2,” “3” distributed on the plane 38 mm away from the developed AIHM working at (a), (f), (k) 18 GHz, (b), (g), (l) 19 GHz, (c), (h), (m) 20 GHz, (d), (i), (n) 21 GHz, and (e), (j), (o) 22 GHz.

Fig. 17. Measured near-field holographic images of capital letters “A,” “B,” “C” distributed on the plane 38 mm away from the developed AIHM working at (a), (f), (k) 18 GHz, (b), (g), (l) 19 GHz, (c), (h), (m) 20 GHz, (d), (i), (n) 21 GHz, and (e), (j), (o) 22 GHz.

Fig. 18. Measured near-field holographic images of capital letters “B” distributed on the plane 80 mm away from the developed AIHM with different radiation angles operating from 18 GHz to 22 GHz.