Anomalous dispersion of waves propagating in multilayer metal-dielectric structures

In this paper, we consider the dispersion characteristics (DCs) of a symmetric metal-dielectric structure (MDS) with two electromagnetically coupled wave-guiding layers (WLs) of the same height b₂ and permittivity ε₂. A separating layer (SL) (ε₁) of height 2b₁ is sandwiched between the WLs. Each WL is separated from a metal screen (MS) by and intermediate layer (IL) (ε₃) of height b₃. The permittivities satisfy the inequalities ε₂ > ε₁ > ε₃. We consider an MDS in which ε₁ = ε₃ and b₁ = b₃. For such an MDS, the dispersion equation (DE) can be obtained from the generalized equations.