Transmission Lines Emulating Moving Media

TL;DR

This paper demonstrates how to emulate electromagnetic phenomena of moving media using stationary artificial transmission lines, enabling exploration of superluminal and complex velocities without physical motion.

Contribution

It introduces nonreciprocal periodically loaded transmission lines that mimic moving media, including experimental validation and analysis of composite right/left handed structures.

Findings

Transmission lines can emulate moving media phenomena.

Experimental and numerical validation of the proposed structures.

Potential applications in engineered electromagnetic materials.

Abstract

In this paper, we show how the electromagnetic phenomena in moving magnetodielectric media can be emulated using artificial composite structures at rest. In particular, we introduce nonreciprocal periodically loaded transmission lines which support waves obeying the same rules as plane electromagnetic waves in moving media. Because the actual physical structure is at rest, in these transmission lines there are no fundamental limitations on the velocity values, which may take values larger than the speed of light or even complex values (considering complex amplitudes in the time-harmonic regime). An example circuit of a unit cell of a "moving" transmission line is presented and analyzed both numerically and experimentally. The special case of composite right/left handed host line is also studied numerically. Besides the fundamental interest, the study is relevant for potential applications in realizing engineered materials for various transformations of electromagnetic fields.