In this paper, TE guided modes of a grounded left-handed (LH) slab waveguide are theoretically investigated. It will be demonstrated that LH slab waveguides, unlike right-handed (R wa veguides, possess stop-bands in two frequency ranges. It is also discussed that LH slab waveguides can
support propagation of slow waves and show stopbands for these waves at higher frequencies. Existence of the stop-bands is an indication of LH properties, so that it can be exploited to identify LH dielectrics form RH ones
