Waveguide containing a backward-wave slab

TL;DR

This paper theoretically analyzes a two-layer waveguide with a backward-wave slab, revealing the existence of super-slow waves with extremely short wavelengths and unique eigenwave properties.

Contribution

It introduces a novel waveguide design incorporating a backward-wave material, demonstrating the support of super-slow waves and analyzing their eigenmodes.

Findings

Existence of TE and TM eigenwaves with exponential decay at the interface

Support for super-slow waves with infinite slow-wave factor at low frequencies

Unique spectral properties of the waveguide with backward-wave material

Abstract

We have considered theoretically the waveguide properties of a plane two-layered waveguide, whose one layer is a usual magnetodielectric (forward-wave medium), but another one is a slab of so-called backward-wave material (BW-material), whose both permittivity and permeability are negative. We have analyzed the properties of eigenwaves in this waveguide. In particular, it was found that there exist waves of both TE and TM polarizations, whose fields decay exponentially from the interface of the two slabs inside both layers, and their slow-wave factor tends to infinity at small frequencies. Thus, this waveguiding system supports super-slow waves with extremely short wavelengthes, as compared to the free-space wavelength and the cross section size. Other peculiarities of the spectrum are also discussed.