Surface-wave suppression in a double-negative metamaterial grounded slab

Surface-wave propagation in a metamaterial grounded slab is investigated. In particular, a double-negative (DNG) medium is considered. On the basis of the dispersion equations for TE and TM surface waves supported by such a grounded slab, conditions are presented which ensure the suppression of a guided-wave regime for both polarizations. In contrast with ordinary grounded slabs, two kinds of surface waves (one evanescent only in air, the other evanescent both in air and inside the slab) have to be taken into account. The possible absence of any surface wave makes the considered structure a promising candidate as a substrate for microstrip antennas with reduced edge-diffraction effects and enhanced radiation efficiency.