A 3D-Printed Millimeter-Wave Free-Form Metasurface Based on Automatic Differentiable Inverse Design

This paper introduces an inverse design framework of metasurface based on the automatic differentiable rigorous diffraction interface theory. As a technical demonstrator, an optimized dual-layer free-form beam-deflector operating at 19 GHz was optimized through the proposed framework and fabricated employing 3D-printing technologies. The simulated and measured results validate that the optimized meta-device achieved the design goal of boosting the first-order transmission efficiency by close to 50%, covering a bandwidth from 18–20 GHz. The inverse design framework proposed in this work, integrating with the 3D-printing technologies, offers a promising way of fast design and validations of metasurfaces for millimeter-wave applications.