Effects of normal and oblique incidence on zero-(n)over-bar gap in periodic lossy multilayer containing double-negative materials

In this paper the transmission of electromagnetic waves through a one-dimensional lossy photonic crystal consisting of layers with negative and positive refractive indices is investigated. The behavior and characteristics of the bandwidth, the depth and the central frequency of the zero-(n) over bar gap for different incidence angles, polarization, loss factor and ratios of thickness of the layers are studied. The results show that the gap is very sensitive to the incidence angle, polarization and the thickness ratio, but it is nearly insensitive to small loss factor. Such properties are quite useful in designing new types of edge filters and other optical devices in microwave engineering. (C) 2012 Elsevier B.V. All rights reserved.