Steerable and compact antenna using a cavity-based metamaterial

During recent years partially reflective surface´s based on artificial conductor are used to create the design of directive and compact cavity antenna. In this paper, we study a design of a locally phase-varying metamaterial working near 10 GHz. It is made from a capacitive and an inductive grid. The phase-varying behavior is obtained with a regular increment of the gap between each unit cell of the capacitive grid in E field direction. This composite metamaterial is used as a partially reflecting surface in a resonant Fabry-Perot type cavity together with a patch antenna to constitute a compact (λ/28) steerable directive printed antenna. An 18° deflection of the antenna beam clockwise and 7° anticlockwise in H plane are obtained and a gain improvement is realized.