3-D-Printed Dielectric Metasurfaces for Antenna Gain Improvement in the Ka-Band

Abstract

In this letter, we design and fabricate a three-dimensional printed all-dielectric planar metalens for microwave focusing into a receiving antenna. The structure allows the antenna gain to be increased by 7.5 dB at 32.5 GHz with a bandwidth of 2.4 GHz. The metalens has a focus full-width at half-maximum of ~0.85λ with a 3 dB depth-of-focus of approximately 5 cm. We show that the antenna half-power beamwidth can be reduced from 36° to 3° in the azimuthal plane and from 4.5° to 3° in the elevation plane with the help of the metalens. In addition, we demonstrate that the metalens performs equally well at oblique incidence, with a 50° and 40° span in the azimuthal and elevation planes, respectively.