Field propagation of a metallic grid slab that acts as a metamaterial

A metallic grid slab has been shown to work as a novel metamaterial which can shape the divergent field emitted from an embedded monopole microwave antenna into a directive transmission at a specific frequency. The transmission of such subwavelength slab remains an issue of challenge. In this work, we experimentally investigate the transmitted behavior of such subwavelength grid slab to explore the underlying mechanism of wave propagation. It is found that there is a large tolerance of directive emission even with a tilted slab. The deviation along the directive emission direction is analyzed based on the interference theory.