Comments on "subwavelength focusing using a negative-refractive-index transmission line"

I. CORRECTED THE RADIAL TL IMPEDANCE FORMULAS FOR THE TL MESH AND THE DUAL TL The above paper [1] analyzes 1) negative-refractive-index transmission-line lens; 2) subwavelength focusing. Unfortunately, there are some errors in the derivations of the radial TL impedance expressions for the TL mesh and the dual TL. Despite this, one should honor the achievements in the paper in which Grbic and Eleftheriades present simulations demonstrating subwavelength focusing of electromagnetic waves.