The pair structure and the photonic crystal heterostructure consisting of ε-negative and μ-negative materials are successfully fabricated by using the transmission line approach.We experimentally investigate the tunneling mode properties by simulating and measuring the scattering parameters and phase shifts.It is shown that the pair structure and the photonic crystal heterostructures possess tunneling modes when the general zero average permittivity and zero average permeability condition are satisfied.At the tunneling frequency,the field (voltage)mainly concentrates in the center of the constructed structures based on the amplification of the evanescent wave.Moreover,the tunneling mode of the photonic crystal heterostructure has zero phase delay.The characteristics have potential applications in design of zero phase delay filters.
