High‐Speed Wide‐Angle Sensing and Imaging by WideBand Metasurfaces with Joint Frequency, Polarization, and Spatial Diversities
Baiyang Liu, Jinyu Wu, Qingfeng Zhang, Hang Wong
Abstract
Abstract High‐speed wide‐angle radio detection is crucial for intelligent wireless systems, autonomous vehicles, rescue operations in urgent situations, and security in various fields. This can be achieved through diverse controls of electromagnetic waves. Currently, multidimensional manipulations of electromagnetic waves are determined by dynamic antennas like phased arrays, mechanical beam‐steering radars, and programmable metasurface imagers. However, these methods face challenges in achieving rapid responses and large data collection intervals for high‐speed sensing and imaging, due to limitations in the speedy explication of analog‐to‐digital (AD) converters, electronic switches, phase shifters, and stepped motors for radiation beam reconfigurations. To address these challenges, advanced microwave‐to‐millimeter‐wave metasurfaces are introduced, designed to offer joint frequency, polarization, and spatial diversities. The metasurface with a disordered atom permutation enables wide‐angle sensing for accurate trajectory tracking of moving objects. On the other hand, a dispersion‐engineered atom arrangement allows the metasurfaces to facilitate wide‐angle through‐wall imaging, effective in detecting objects of varied shapes and positions. The experiments reveal that these metasurfaces can reconstruct objects at 100 frames per second (fps) from a single‐shot measurement, allowing 0.3x speed playback for detailed analysis. This demonstrates their potential in high‐speed sensing and imaging. Such a breakthrough is pivotal in unveiling new modalities and expanding possibilities in real‐time radio applications, including smart transportation, all‐condition surveillance, perspective radio, and integrated sensing and communication (ISAC) systems, especially relevant to technologies of 6G and beyond.