Direct calculation of permeability and permittivity for a left-handed metamaterial

Recently, an electromagnetic metamaterial was fabricated and demonstrated to exhibit a left-handed (LH) propagation band at microwave frequencies. A LH metamaterial is one characterized by material constants-the permeability and permittivity-which are simultaneously negative, a situation never observed in naturally occurring materials or composites. While the presence of the propagation band was shown to be an inherent demonstration of left handedness, actual numerical values for the material constants were not obtained. In the present work, using appropriate averages to define the macroscopic fields, we extract quantitative values for the effective permeability and permittivity from finite-difference simulations using three different approaches. (C) 2000 American Institute of Physics. [S0003-6951(00)03440-9].