Analysis of Scattering and Radiation Characteristics for Stepped Left-handed Slab Waveguide Operating in Evanescent Surface Mode
The scattering and radiation characteristics of a step discontinuity in left-handed (LH) slab waveguide operating in evanescent surface mode are analyzed by a method, which combines the rigorous mode-matching method with the multi-mode network theory. In the analysis the radiation problem is transformed into a propagation problem so as to tremendously simplify the calculation procedure. The backward radiation of the stepped LH guide is clearly demonstrated. The frequency scanning characteristics of the step are just opposite to that of the ordinary antenna, which makes the considered structure promising candidate for new type of planar antennas. Material with both negative permittivity and permeability referred to as left-handed medium was theoretically analyzed by V. G. Veselagop 1 in 1967. In recent years, different fundamental issues related with the medium have been investigated, including the dispersion of guided waves in the LH material 2. The present analysis verifies that there are two kinds of eigen surface waves for LH slab structure, the ordinary surface wave and the evanescent surface wave. The former has real transverse wavenumber and propagating inside the slab; the latter has positive imaginary transverse wavenumber and hence increasing inside the slab. The dispersion properties of both two kinds of surface waves are examined as in Figure 2, from which the existence of the evanescent surface mode is justified in the left-hand region. Figure 3 shows the radiation patterns of the stepped structure at different frequencies, from which the backward radiation property and the opposite frequency scanning characteristic of the stepped LH waveguide is clearly illustrated.
Meng Huang Shanjia Xu
Department of Electronics Engineering and Information ScienceUniversity of Science and Technology of China, Hefei 230027, China
国际会议
Progress in Electromagnetics Research Symposium 2007(2007年电磁学研究新进展学术研讨会)(PIERS 2007)
北京
英文
137-138
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）