NTT DOCOMO working in collaboration with the global glass manufacturer AGC has successfully conducted the world’s first trial of a prototype transparent dynamic metasurface using 28 GHz 5G radio signals.
The new metasurface achieves dynamic manipulation of radio-wave reflection and penetration in a highly transparent package suitable for unobtrusive use in the windows of buildings and vehicles as well as on billboards.
AGC manufactured the optically transparent metasurface using microfabrication techniques, based on a theoretical model proposed and designed by DOCOMO.
The metasurface, an artificially engineered material, comprises a large number of sub-wavelength unit cells placed in a periodic arrangement on a two-dimensional surface covered with a glass substrate. Moving the glass substrate slightly enables dynamic control of radio waves in three modes: full penetration of incident radio waves, partial reflection of incident radio waves and full reflection of all radio waves.
The new technology deployed in the activation of the transparent metasurface also works with frequencies higher than those used for 5G. Going forward, in addition to incorporating the technology in methods for efficiently and flexibly establishing 5G access areas, DOCOMO will further research and develop the technology for use with newer wireless communication systems.
In the trial, radio waves were beamed perpendicularly to measure penetration in two modes: full penetration, where the metasurface substrate and movable transparent substrate were attached to each other, and full reflection, where the metasurface substrate and movable transparent substrate were separated by more than 200 micrometers.
Tests of both modes at 28 GHz produced successful results. Radio waves passed through the substrate in penetration mode and were blocked in reflection mode, in both cases without attenuation.