Abstract: In this paper, subwavelength dielectric blocks with varying thicknesses are introduced to realize 0 ~ 2π phase change. Based on Huygens' metasurface principle, such nonuniform building blocks are used to design an electrically- thin all-dielectric electromagnetic (EM) lens operated at 28 GHz communication band. The ratio of the focal length to aper- ture diameter (F/ D) of the lens is 0. 15. The EM lens is fabricated by a three-dimensional (3D) printer, and is integrated with a substrate-integrated waveguide (SIW) patch antenna to form an ultra low-profile lens antenna system. Both the simu- lated and measured results show that the all-dielectric lens can lead to about 7 dB gain increment and the great reduction of the 3 dB beamwidth, as well as very low side-lobe levels.