Exploring the use of metamaterial apertures in a millimeter-wave imaging system

We demonstrate a low-profile, holographic imaging system at millimeter wavelengths based on a frequency-diverse metasurface aperture. From measurements of spatially diverse field patterns, diffraction-limited images of human-scale targets can be reconstructed at diffraction and bandwidth limits. The system is driven by a single microwave source swept over a band of frequencies (18–26.5 GHz) and switched between pairs of metasurface panels. High fidelity image reconstruction requires a precise model for each field pattern generated by the aperture. This constraint makes scaling of computational imaging systems to large apertures inherently challenging. To meet the demanding requirements, we introduce computational methods and calibration approaches that enable rapid and accurate imaging performance.