Broadband phase retarder based on one-dimensional Thue-Morse structure containing single-negative materials

By means of transfer matrix method, a numerical study of the properties of the reflection phase shifts and the reflection phase difference between TE and TM waves in a one-dimensional Thue-Morse quasicrystal composed of single-negative materials are presented within the zero-ϕeff gap. The results indicate that the phase difference between TE and TM reflected waves can remain constant in a rather wide frequency range within the gap for a given incident angle. The dependence of the reflection phase difference on the ratio of the thicknesses of the two single-negative materials as well as on the difference scaling factor of the layers is investigated. It is also found that the reflection phase difference between the two polarizations can increase (or decrease) continuously from 0 to π (or 0 to −π) radian with the increasing of the incident angle. Meanwhile, the frequency range with stable phase difference between the two polarizations can be adjusted through changing the permittivity and permeability. These results would be useful to realize the broadband phase retarders within the zero-ϕeff gap.