Asymmetric transmission and absorption generated with three-dimensional metamaterials at oblique incidence

A novel metamaterial device with simultaneous asymmetric transmission and absorption has been proposed. The proposed device is made of two artificial metallo-dielectric layers which are perpendicular to each other. The three-dimensional structure is light-weight and does not alter the polarization of waves for the lack of Faraday rotation. The transmission is asymmetric, when TE wave propagates from the front side to back side at 30°. In such a case, the transmission coefficients are 0.81, 0.17 and 0.82, at f1 = 1.72GHz, f2 = 2.3GHz, and f3 = 3.48GHz, respectively. When the TE wave is back propagating (from the back side to front side) at the same incident angle, the transmission coefficients are changed to 0.81, 0.17 and 0.82, at f1 = 1.72GHz, f2 = 2.3GHz, and f3 = 3.48GHz, respectively. The similar asymmetric phenomena also can be seen in the absorption. The asymmetric transmission and absorption have been elucidated with tangential surface parameters, which provides the physical intuition. Finally, the proposed device has been fabricated and measured, and the experimental results agree reasonably well with theoretical simulations.