Broadband, Wide-Angle, and Versatile Metasurface Illusions with Inverse Synthetic Aperture Radar Imaging.

Generation of controllable illusions has raised widespread interest. Over the past few decades, this field has been revolutionized by the emergence of metamaterials and metasurfaces. However, current efforts utilizing single-layer metasurfaces are limited to simple illusion demonstrations by reproducing electromagnetic field distributions, which also struggle to achieve both broad bandwidths and wide angular ranges. Here, a nontrivial multi-layer illusion strategy is proposed utilizing the inverse synthetic aperture radar imaging. The customization of illusions is facilitated by correlating the phase dispersion of meta-atoms within the target frequency interval with the positioning of the structure. The approach enables the creation of illusions across a broadband of 8 to 12 GHz and a wide angular range from -30° to 30°. As a proof of principle, several illusions are experimentally demonstrated, showcasing the diversity of the approach. This work presents a viable illusion strategy that is more feasible for practical applications in the microwave domain, paving the way for future advances of customizable illusions.