Metamaterial Loadings for Waveguide Miniaturization

TL;DR

This paper demonstrates that loading rectangular metallic waveguides with metamaterial elements like ELCs and SRRs enables operation below cutoff frequency and allows independent control of wave propagation modes.

Contribution

It introduces a novel waveguide loading technique using metamaterials to achieve miniaturization and mode control, including dual loading with ELCs and SRRs for versatile propagation.

Findings

Waveguides loaded with ELCs operate below cutoff frequency.

Doubly-loaded waveguides support both forward and backward waves.

Independent control of propagation characteristics is achieved.

Abstract

We show that a rectangular metallic waveguide loaded with metamaterial elements consisting of electric-field coupled (ELC) resonators placed at the side walls can operate well below the cutoff frequency of the respective unloaded waveguide. The dispersion diagrams indicate that propagating modes in ELC-loaded waveguides are of forward-type for both TE and TM modes. We also study the dispersion diagram and transmission characteristics of rectangular metallic waveguides simultaneously loaded with ELCs and split ring resonators (SRRs). Such doubly-loaded waveguides can support both forward wave and backward waves, and provide independent control of the propagation characteristics for the respective modes.