Zero--n Gaps of Photonic Crystals Consisting of Normal and CRLH Transmission Lines

In this paper, we successfully fabricated one-dimensional photonic crystals and quasiperiodic structures composed of positive refractive materials (PIMs) and negative refractive materials (NIMs) by using conventional transmission line units and CRLH-TL units. The dispersion relation of photonic crystals was calculated by transfer matrix with the specific experimental parameters. ^-_n = 0 will result in the existence of the spectral gap that is invariant with respect to the changes of scale length, and the edges of the zero-^-_n gap are determined by ^-_ϵ = 0 and ^-_μ = 0 respectively. We experimentally demonstrate the characteristics of the zero-^-_n gap, which is helpful to design and adjust the special gap to use in microwave engineering