Electromagnetic Imaging and Sensing with Metasurface-Based Antennas

Computational electromagnetic imaging has emerged as an alternative to conventional imaging systems, such as those based on synthetic aperture radar. This chapter delves into this novel imaging modality, which resorts to compressive antennas to achieve physical layer compression. After presenting the forward model that governs this type of imaging system as well as several reconstruction techniques, the focus is shifted towards the hardware layer. In particular, it is revealed how compressive antennas and, especially, reconfigurable metasurface-based apertures, are instrumental in computational imaging systems. This is because these antennas can be engineered to radiate spatially diverse patterns, which is crucial to encode the scene information into a reduced number of radio-frequency channels. Then, several use cases showcasing the advantages accomplished by this technology in terms of reduced hardware complexity and faster data acquisition speed are presented. Finally, the chapter concludes with some final remarks, emphasizing the potential of computational electromagnetic imaging and further highlighting the key improvements achieved leveraging this technology.