A Transmissive Coding Metasurface

A transmissive metasurface is proposed in this paper. The metasurface consists of three substrates gaped by air, where the same metallic slot ring is attached to each substrate respectively. To facilitate the dynamic control of the transmission coefficient, the varactor diodes are employed across the slots in the element. By changing the biasing states of the varactor diodes, the metasurface can switch between two distinct phase states of 0 and π to manipulate wave propagation behaviros. A microstrip array antenna is designed to feed the metasurface in the experiment.