An Ultralow-profile Lens Antenna Based on All-dielectric Metasurfaces

In this paper, subwavelength dielectric unit cells (about 0.3 lambda(0) x 0.3 lambda(0), lambda(0) is the operating wavelength in free space) with different thicknesses are introduced to achieve 0 similar to 2 pi phase changes. Such nonuniform building blocks are used to design an electrically-thin electromagnetic lens operated at 28-GHz communication band. Then, the lens is fabricated through a three-dimensional (3D) printer, and integrated with a patch antenna to form an ultralow-profile lens antenna system. The ratio of the focal length to aperture diameter (F/D) is set to be 0.15. Both the simulated and measured results show that the all-dielectric lens can lead to about 7 dB gain increment and very low side-lobe levels.