Reflectionless Sharp Bends and Corners in Waveguides Using Epsilon-Near-Zero Effects

TL;DR

This paper demonstrates that epsilon-near-zero metamaterials enable waveguides with sharp bends and corners that do not cause reflections or losses, leveraging anomalous tunneling effects at the waveguide's cutoff frequency.

Contribution

The study provides experimental evidence that zero-permittivity metamaterials can be used to create reflectionless sharp bends in waveguides, expanding the potential for efficient waveguide design.

Findings

Sharp bends in waveguides cause negligible reflection and loss.

Epsilon-near-zero effects enable energy tunneling through ultranarrow channels.

Experimental validation of zero-permittivity waveguide behavior at cutoff frequency.

Abstract

Following our recent theoretical and experimental results that show how zero-permittivity metamaterials may provide anomalous tunneling and energy squeezing through ultranarrow waveguide channels, here we report an experimental investigation of the bending features relative to this counterintuitive resonant effect. We generate the required effectively-zero permittivity using a waveguide operating at the cut-off of its dominant mode, and we show how sharp and narrow bends may be inserted within the propagation channel without causing any sensible reflection or loss.