Rigorous mode‐matching analysis of energy tunneling through an ultranarrow epsilon‐near‐zero channel

On the basis of the rigorous mode-matching procedure, we demonstrate theoretically that electromagnetic waves can be squeezed and tunneled through very narrow channel waveguides at cutoff frequency, which mimics the response of e-near-zero (ENZ) materials. Because of the infinite phase velocity of the wave propagation in ENZ material, this tunneling phenomenon possesses distinct anomalous properties: the phase of the wave along the narrow channel is almost uniform and it is fundamentally independent of its geometry. All of these theoretical predictions agree well with the experimental results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 163–166, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23994