On the coaxial excitation of the modified Goubau line

The problem of excitation of the modified Goubau line from a coaxial junction is analyzed using the Wiener‐Hopf technique and Fourier transforms in the axial direction. The analytical expressions reduce to those of Ledeboer in the absence of the air gap. The effects of the air gap in reducing the input reflection coefficient and in modifying such other parameters as the launching efficiency and propagation constants for different frequencies are illustrated with numerical examples.