This paper presents the design of a metamaterial in planar form by focusing on the phase properties of its basic elements. These elements must transmit a wave with phase advancement to get a metamaterial showing a negative refractive index. This is obtained by delaying the phase within the basic element by almost −2π, which from outside the element looks like an advancing phase. Simulations demonstrate the behavior of one element, a 1D structure and a 2D structure. The propagating backward wave is traced on terminals of particular elements.