Stacked complementary metasurfaces for ultraslow microwave metamaterials

We have experimentally realized at microwaves a dual-band ultraslow regime by constructing a metamaterial based upon the alternative stack of conventional-and complementary-split-ring-resonators-surfaces. The group delay reaches values larger than two orders of magnitude than those obtained when the electromagnetic wave propagates the same thickness in free-space. The ultraslow waves have been initially predicted by a numerical eigenmode analysis and finite-integration frequency domain simulations. Such ultraslow modes can be integrated into free-space technology for spatial delay lines, and traveling wave amplifier as well as sensors due to the enhanced interaction between different beams or radiation and matter. (C) 2010 American Institute of Physics. [doi:10.1063/1.3413958]