Experimental investigation of waveguide filled with uniaxial thin-wire-based ENG metamaterial

Recently, it has been shown that a rectangular waveguide filled with uniaxial thin-wire-based ENG filling supports backward-wave propagation below cut-off frequency of the fundamental TM₁₁ mode. The main advantage of this waveguide, comparing to previously investigated dual case (rectangular waveguide with uniaxial MNG filling), is inherently low loss caused by the non-resonant nature of ENG filling. This paper reports experimental investigation of the basic properties of ENG-based waveguide with square and circular cross-section, operating in 10 GHz band. Measured transmission coefficients, inherent phase shift per unit cell and phase distributions were found to be in very good agreement with theoretical predictions