Propagation properties of the surface-wave-like mode in slot line are
investigated with the spectral domain analysis, This surface-wave-like
mode is an odd dominant mode with a magnetic wall symmetric plane pla
ced at the center of the slot, Its field distribution is similar to th
at of the TM(0) mode supported by the surrounding structure, It exists
in the lower frequency regime and evolves into a nonphysical and nons
pectral real mode in the higher frequency regime, Unlike other surface
-wave-like modes in planar transmission line, the surface-wave-like mo
de in slot line does not evolve into a leaky mode.