|Title||Experimental demonstration of electromagnetic tunneling through an epsilon-near-zero metamaterial at microwave frequencies|
|Publication Type||Journal Article|
|Year of Publication||2008|
|Authors||R..P. Liu, Q.. Cheng, T..H. Hand, J.J. Mock, T..J. Cui, S..A. Cummer, D.R. Smith|
|Journal||Physical Review Letters|
Silveirinha and Engheta have recently proposed that electromagnetic waves can tunnel through a material with an electric permittivity (epsilon) near zero (ENZ). An ENZ material of arbitrary geometry can thus serve as a perfect coupler between incoming and outgoing waveguides with identical cross-sectional area, so long as one dimension of the ENZ is electrically small. In this Letter we present an experimental demonstration of microwave tunneling between two planar waveguides separated by a thin ENZ channel. The ENZ channel consists of a planar waveguide in which complementary split ring resonators are patterned on the lower surface. A tunneling passband is found in transmission measurements, while a two-dimensional spatial map of the electric field distribution reveals a uniform phase variation across the channel-both measurements in agreement with theory and numerical simulations.