NEAR-FIELD MEASUREMENTS OVER EXPERIMENTAL MODIFIED GOUBAU LINE.

Previous theoretical investigations on the introduction of a narrow circumferential airgap between the conductor and inner dielectric surface of a conventional Goubau line indicated certain improvements in so far as the propagation characteristics are concerned. This paper describes the near-field measurements of an experimental line constructed for the purpose of verification of some of the results. The measured values of the guide wavelength, as determined from the standing waves set up on the line, closely follow the predicted values calculated from the boundary value solution. The power decay in the radial direction also follows the theoretical or calculated pattern, and these results tend to give a qualitative confirmation to the existence of surface waves on such a modification of the Goubau line.