Physical Design and Experimental Verification of a Huygens' Metasurface Two-lens System for Phased-array Scan-angle Enhancement

TL;DR

This paper presents a physical Huygens' metasurface two-lens system that doubles the scan angle of a phased-array antenna at 10 GHz, verified through simulations and experiments, with minimal scan errors.

Contribution

The work introduces a novel two-lens metasurface system using wire-loop unit cells for high transmission and demonstrates its effectiveness in scan-angle doubling through comprehensive analysis and experimental validation.

Findings

Scan angle doubles for incident angles below 15°

Experimental results show ±2° scan errors

Good agreement between simulation and experiment

Abstract

Over the past decades, many radome designs to extend the angular scan range of phased-array antennas have been devised by utilizing dielectric materials and metamaterials. More recently, metasurface technology such as planar lenses and beam deflectors have been applied to phased arrays, enabling scan-angle enhancers to have a low profile. In this work, a physical Huygens' metasurface (HMS) two-lens system for scanangle doubling of a phased array is presented. For the HMS unit cells, the wire-loop topology is deployed to achieve high transmission for the required phase-angle shift. The proposed two-lens system is analyzed by full-wave simulations and experiments. The simulation results demonstrate that the scan angle doubles when the incident angle is below 15{\deg} in accordance to the design specification. Furthermore, the directivity degradation of the refracted beams by the two-HMS lenses is in good agreement with theory. Finally, a fabricated two-lens system with two 15{\lambda} long by 15{\lambda} wide metasurface lenses and a 16{\times}16-element patch antenna array as a source is experimentally verified at 10 GHz. The experimental results are in good agreement with the simulated results by showing angle-doubling performance with {\pm}2{\deg} scan errors.