Sideband-free space-time-coding metasurface antennas

Authors：Wu, Geng-Bo; Dai, Jun Yan^*; Cheng, Qiang^*; Cui, Tie Jun^*; Chan, Chi Hou^*

Source：Nature Electronics, 2022, 5(11): 808-819.

DOI：10.1038/s41928-022-00857-0

• LIGHT
• METAMATERIALS

Applications such as microwave wireless communications, optical light fidelity, and light detection and ranging systems require advanced interfaces that can couple guided waves from in-plane sources into free space and manipulate the extracted free-space waves. Spatiotemporally modulated metasurfaces can control electromagnetic waves, but such systems are typically limited to free-space-only and waveguide-only platforms. Here we report a 1-bit space-time-coding metasurface antenna that can extract and mould guided waves into any desired free-space waves in both space and frequency domains. The waveguide-integrated metasurface antenna also provides a self-filtering phenomenon that overcomes the issue of sideband pollution found in traditional spatiotemporally modulated metasurfaces. To illustrate the capabilities of the approach, we use the metasurface antenna for high-efficiency frequency conversion, fundamental-frequency continuous beam scanning and independent control of multiple harmonics. @@@ A 1-bit space-time-coding metasurface antenna can extract and mould guided waves into any desired free-space waves in both space and frequency domains.