Dynamic Metasurface Antenna-Based Mills-Cross Aperture for 3-D Computational Microwave Imaging

This work presents a computational imaging (CI) system capable of retrieving 3-D images of the area under inspection. The system is based on the use of two linear dynamic metasurface antennas (DMAs) specifically designed and fabricated for this purpose. The developed DMAs are able to generate the spatially-incoherent radiation patterns (or measurement modes) required by CI systems to compress the scene information by reconfiguring their radiating apertures. This reconfiguration is achieved by tuning the unit cells that populate them on and off using p-i-n diodes. The two DMAs are arranged in a Mills-Cross configuration, which enables to synthesize a 2-D effective aperture and, as a result, to reconstruct 3-D radar images. The performance of the proposed system has been experimentally validated, showing its capability to retrieve high quality images of different targets with a low clutter level. Furthermore, the impact of the number of masks (i.e., sets of tuning states of the diodes) on the quality of the radar images has been evaluated both qualitatively and quantitatively.