Computational Imaging With Dynamic Metasurfaces: A Recipe for Simple and Low-Cost Microwave Imaging
Timothy Sleasman, Mohammadreza F. Imani, Aaron V. Diebold, Michael Boyarsky, Kenneth P. Trofatter, David R. Smith
Abstract
We review the evolution of metasurface antennas for computational microwave imaging and highlight the advantages and disadvantages of various configurations. As an illustrative example, we examine a computational imaging system comprising dynamic printed metasurface cavities as modular building blocks. These metasurface cavities can generate a multitude of spatially diverse, voltage-controlled illumination patterns, and can therefore encode a scene’s reflectivity distribution into a set of measurements that can be postprocessed to produce an image. These single-port devices act as transmitters (Txs) and/or receivers (Rxs) and can be combined to create an electrically large aperture with a reduced number of (expensive and cumbersome) radio-frequency (RF) components. Here, we present some of the unique possibilities made possible by a dynamic metasurface imager. Specifically, we demonstrate high quality imaging with a reduced bandwidth of operation—as narrow as a single frequency. We then provide performance predictions for the case when dynamic metasurface cavities are used to image humans, as might be relevant in many security-screening applications. We conclude by describing the outlook of metasurfaces for imaging and identifying several future directions.