Mode bifurcation and fold points of complex dispersion curves for the negative index metamaterial Goubau line

In this paper the complex dispersion curves of the four lowest-order transverse magnetic modes of a dielectric Goubau line (epsilon > 0, mu > 0) are compared with those of a weakly dispersive negative index metamaterial (NIM) Goubau line. The vastly different dispersion curve structure for the NIM Goubau line is characterized by unusual features such as mode bifurcation, complex fold points, both proper and improper complex modes, and merging of complex and real modes. (C) 2010 American Institute of Physics. [doi:10.1063/1.3465330]