X-band SAR imaging with a liquid-crystal-based dynamic metasurface antenna

Synthetic aperture radar (SAR) synthesizes a large effective aperture via coherent processing of multiple measurements taken from a moving platform. We present an approach for SAR imaging using an X-band (10–13.7  GHz) dynamic metasurface antenna (MSA). This newly developed antenna has over 6000 liquid-crystal-switched radiating elements that cover a circular area with an approximate diameter of 0.45 m. The MSA’s main beam can be steered electronically to spherical angles of up to ±70°. To the best of our knowledge, we present the first-reported laboratory-scale imaging experiments with a liquid-crystal-switched MSA. We leverage the beam-steering capabilities of the MSA in a spotlight SAR mode to achieve a measured cross-range resolution of 1.6 cm, a 62% improvement over the 4.2 cm cross-range resolution achieved with the same aperture without the metasurface-enabled beam steering. The dynamic MSA offers the superior image resolution of a beam-steering device without the hardware burden of conventional phased array antennas.