In this note, we present the analysis for the radiation from a traveling-wave infinitely-extent sheet of monochromatic electric current that is placed at the interface between a conventional lossless dielectric and a lossless material possessing negative real permittivity and permeability. The field distributions and the direction of the Poynting vectors in both half spaces are discussed, and some physical remarks are provided. A brief note about launching Zenneck waves by a line current along this interface is also mentioned.