NTT DOCOMO in collaboration with the global glass manufacturer AGC recently conducted what is believed to be 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. Compared to conventional methods using semiconductors, this new design offers two advantages: it allows dynamic control while maintaining transparency of the window and it facilitates enlargement of the substrate.
The metasurface can manipulate radio waves in accordance with the specific installation environment, particularly in locations not suited to the installation of base stations, such as built-up areas or in indoor areas where reception needs to be blocked selectively, such as in high-security areas. Also, the transparent substrate does not interfere aesthetically or physically with the surrounding environment or people's line of sight, making it ideal for use within buildings and on vehicles or billboards, for example.
