Scattering and Radiation Characteristics of Step Discontinuity in Left-Handed Slab Waveguide Operating in Evanescent Surface Mode

The radiation characteristics of a step discontinuity in left-handed (LH) slab waveguide operating in evanescent surface mode are analyzed. Our method transforms the radiation problem into a propagation problem so as to tremendously simplify the calculation procedure. The dispersion properties of the slab are examined, from which the left-hand property of the operating mode is testified. The relative scattered power and radiation pattern of the step are given for the first time, from which the backward radiation of the stepped LH guide is clearly demonstrated. The opposite frequency scanning characteristic of the step is illustrated, which makes the considered structure promising candidate for new type of planar antennas.