Time-Encoding Design of Digital Coding Metasurface for Independent Control of Multi-Harmonics' Amplitudes and Phases

Space-time-coding digital metasurfaces have expanded the applications of metasurfaces in both space and frequency domains. However, independent control of amplitudes and phases of multiple harmonics remains a challenge. In this paper, a novel time-domain coding strategy is presented to generate multiple harmonics and disentangle their amplitudes and phases. The coding sequences are created by innovatively intertwining a series of sub-sequences, which are designed based on theoretical derivations without any need for a complex optimization process. The proposed approach will provide valuable inspiration for the multi-harmonic regulation of space-time coding metasurfaces and lay a solid foundation for various applications in frequency division multiplexing wireless communications.