Propagation characteristics of a loose braid coaxial cable in free space

A loose braid coaxial cable is studied and two possible interpretations of the surfacetransfer impedance sign give two mathematical solutions of the characteristic equation; the two solutions correspond to two different modes, the coaxial and the `Goubau¿ modes, which maypropagate according to two different launching processes. Solutions for the propagation constant, distribution of power between the inside and the outside of the coaxial structure, and outside radial decay are presented.