Implementation and Characterization of a Two-Dimensional Printed Circuit Dynamic Metasurface Aperture for Computational Microwave Imaging

We present the design, fabrication, and experimental characterization of a 2-D, dynamically tuned, metasurface aperture, emphasizing its potential performance in computational imaging applications. The dynamic metasurface aperture (DMA) consists of an irregular, planar cavity that feeds a multitude of tunable metamaterial elements, all fabricated in a compact, multilayer printed circuit board process. The design considerations for the metamaterial element as a tunable radiator, the associated biasing circuitry, as well as cavity parameters are examined and discussed. A sensing matrix can be constructed from the measured transmit patterns, the singular value spectrum of which provides insight into the information capacity of the apertures. We investigate the singular value spectra of the sensing matrix over a variety of operating parameters, such as the number of metamaterial elements, number of masks (aka tuning states), and number of radiating elements. After optimizing over these key parameters, we demonstrate computational microwave imaging of simple test objects.