Broadband trifunctional metasurface and its application in a lens antenna

Multifunctional metasurfaces have attracted extensive attention due to their ability to achieve diversified wavefront controls in flat devices. To date, most designs through metasurface are confined to realize one or two functionalities. In this work, we implement a broadband trifunctional metasurface by using different meta-atoms of the same type. The meta-atoms can independently manipulate the amplitude and phase of transmitted waves and the phase of reflected waves in a wide frequency range. Thus, they help the metasurface achieving the functionalities of beam deflection, diffuse scattering, and beam focusing according to the polarization and the direction of incident waves. The metasurface is applied to a metalens antenna, which features broadband, low side-lobe, and stealth. The metalens antenna works at the frequency range 9.8 GHz to 11.6 GHz with gain over 25 dBi. Experiments verify the functions of the trifunctional metasurface and are in good agreement with the designs. Our approach provides a solid platform for high-efficiency wideband metadevices with diverse functionalities.