Below-Cutoff Propagation in Metamaterial-Lined Circular Waveguides

TL;DR

This study explores how metamaterial liners in circular waveguides enable novel propagation phenomena like backward waves and miniaturization, with theoretical and simulation validation.

Contribution

It introduces a detailed analysis of dispersive metamaterial liners in waveguides, revealing new propagation effects and methods to engineer their spectral response.

Findings

Backward-wave propagation below cutoff

Resonant tunneling of power

Field collimation and miniaturization

Abstract

This paper investigates the propagation characteristics of circular waveguides whose interior surface is coated with a thin metamaterial liner possessing dispersive, negative, and near-zero permittivity. A field analysis of this system produces the dispersion of complex modes, and reveals in detail intriguing phenomena such as backward-wave propagation below the unlined waveguide's fundamental-mode cutoff, resonant tunneling of power, field collimation, and miniaturization. It is shown how the waveguide geometry and metamaterial parameters may be selected to engineer the lined waveguide's spectral response. Theoretical dispersion and transmission results are closely validated by full-wave simulations.