D.R. Smith

Department of Physics, 0319

University of California, San Diego

9500 Gilman Drive

La Jolla, CA 92093-0319

USA

We have demonstrated, using simulations and microwave experiments,
that a composite medium possessing a frequency band over which the
electric permittivity and magnetic permeability are simultaneously
negative can be constructed. This composite medium, termed a
``left-handed'' medium by V. G. Veselago, has an index of refraction
that is also negative, a property not found in naturally occurring
materials. The fabricated material is a periodic array comprised of
two interleaved composite arrays: a conducting rod medium and a
conducting Split Ring Resonator (SRR) medium. Both of these
constituent materials have been recently analyzed by J. B. Pendry et
al., who showed that the rod medium has a negative permittivity below
a cutoff (or ``plasma'') frequency, and that the SRR medium has a region
of negative permeability. While not immediately obvious, combinations
of these medium result in a composite in which the properties of each
sub-array are retained that is, interaction effects between the rod
and SRR arrays are minimal.

We have utilized a variety of techniques to characterize the composite
media in terms of the bulk material parameters epsilon and mu.
Typically, we perform finite-difference or finite-element simulations
of either a finite or infinite structure, and then interpret the
results by either averaging the local fields to find the ``macroscopic''
fields (for an infinite structure), or performing an S-parameters
inversion (for a finite structure). Both methods provide a means of
characterization, and produce results in agreement with each other and
experimentally obtained data.