  A backward-wave slab based on a capacitively and inductively loaded
three-dimensional transmission-line network is designed in such a way that
impedance-matching with free space is obtained. To enable field propagation
from free space to the network and vice versa, the use of a transition layer is
proposed. Matching of the designed network with free space and negative
refraction occurring at the slab interfaces are confirmed with full-wave
simulations.
