Characteristics of waves guided by a grounded "left-handed" material slab of finite extent.

The properties of waves guided by a plane-parallel finite slab of material having an ideal, homogeneous, and causal permittivity epsilon (f) , and permeability mu (f) , are investigated analytically and numerically through simulations done via a finite difference time domain (FDTD) code. Lorentzian functional forms are chosen for epsilon (f) and mu (f) . Wave guidance is examined for frequency ranges where the material in the slab is in the left-handed material (LHM) regime, i.e., the real parts of epsilon (f) and mu (f) are negative. It is shown that for reasonably thin slabs, and unlike ordinary materials, there is a unique power recirculation or feedback mechanism wherein the fields in the vicinity of the slab exchange power across the free-space/LHM slab interface. Within the LHM slab, the power travels backwards towards the source. This results in significant but bounded energy accumulation near the edge of the slab closest to the source. The energy exchange across the slab interface is necessary in order to sustain the resulting backward wave in the slab. Slabs thicker than a wavelength are also analyzed, leading to a reversal of the power loop description. The agreement between analytical and numerical results is excellent. They confirm the guided wave physics of a LHM slab.