Design aspects of finite periodic transmission lines based on planar structures

The focus of this manuscript is an analysis of various design aspects of composite right-left handed transmission lines (TLs) with emphasis on practical implementation to periodic structures. Existing used design procedures consider the influence of a period to guided wavelength ratio, coupling of parasitic fields, or fabrication inaccuracies to a limited degree. These factors become especially important for composite right/left handed (CRLH) TLs design increasing the frequency of operation. The result of this work is a detailed analysis of finite periodic transmission lines design with regard on the factors mentioned. The optimal value of the period to guided wavelength ratio was found to be 0.1-0.25 for the best trade-off between easy balancing of the unit cell and maintaining the applicability of the Bloch analysis.