3-D Printable Metal-Dielectric Metasurface for Risley Prism-Based Beam-Steering Antennas

Abstract

A 3-D printable, planar, metal-dielectric metasurface-based, 2-D beam-steering system for aperture-type antennas is presented in this paper. This beam-steering system, also known as the near-field meta-steering system, comprises two fully passive phase-gradient metasurfaces placed in the antenna’s near-field region to steer the radiation beam. To address the non-uniform electric field phase of the aperture antenna, phase correction is also incorporated into the bottom metasurface placed on top of the antenna aperture in its near-field to enhance the far-field radiation of the antenna. Near-field phase transformation and phased array antenna theory concepts are applied to design the proposed metasurfaces. Two types of metal-dielectric unit cells are implemented to provide a phase range of 360°. The height of each metasurface is only 6.25 mm ( $0.25\lambda _{0}$ ), and the height of the whole system is only $1.56~\lambda _{0}$ at 12 GHz. The proposed beam-steering system with a resonant cavity antenna can steer the beam to a maximum of ±44° in the elevation plane and 360° in the azimuth plane with only a 1.4 dB (17 dB - 15.6 dB) deviation in directivity over the full steering range.

Keywords

• 3-D printing
• beam-steering
• metasurface
• near-field phase transformation
• near-field meta-steering
• resonant cavity antenna