title: Comment I on "Resonant and antiresonant frequency dependence of the effective parameters of metamaterials".
abstract: Noting that the imaginary parts of the permittivity and permeability of any linear, homogeneous, passive, dielectric-magnetic material are always positive, independent of the signs of their real parts, we conclude that recent claims by Koschny et al. [Phys. Rev. E 68, 065602 (2003)] are unphysical.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Depine
authors.forename: Akhlesh
authors.initials: A
authors.lastname: Lakhtakia