The Design of Broadband, Volumetric NRI Media Using Multiconductor Transmission-Line Analysis

Multiconductor transmission-line (MTL) analysis is used to model a broadband, volumetric negative-refractive-index (NRI) medium. Equations for the two-dimensional dispersion characteristics and the Bloch impedance are derived using a simplified periodic MTL analysis that provides insight into the operation of the NRI structure, while still accounting for spatial dispersion. Equations for the resonant points of the NRI medium are also derived, including the magnetic and electric plasma frequencies and the low-frequency backward-wave cutoff. The nature of each resonant point is discussed as well. Finally, this paper presents the modeling of finite structures with rigorous MTL analysis. Using this method, the reflection and transmission coefficients for normal incidence on a four-cell slab of the NRI medium are calculated and compared to full-wave simulation.