Programmable Coding Metasurface Reflector for Reconfigurable Multibeam Antenna Application

In this article, we propose a method of designing programmable coding metasurface with a reconfigurable number of reflected beams. Each unit cell of the metasurface is loaded with one varactor to enable adjustable phase responses. The bias, beneath the ground drilled with small holes, is connected to unit cells by a thin via through the holes, to avoid adverse influences on unit cells. To simplify the bias network, a super unit composed of
$5 \times 5$
unit cells is taken as the coding element of realizing 2-D coding sequences. With different bias voltages, the unit cell will produce different reflection phases. By programming the bias voltages, the number and directions of reflected beams can be tailored due to different coding sequences. Under normal incident, reflected waves will be split into multiple beams whose directions can be flexibly controlled. We designed a prototype, implemented our design, and carried out experiments. Both the simulation and experiment results show that the number of reflected beams can be reconfigured between 1 and 5. Reflect beam number reconfigurability of such metasurfaces can be readily used as planar reflector of antennas and may find applications in wireless communications.