Evaluation of the group velocity of electromagnetic wave propagation in an inhomogeneous transmission line: the effect of superluminal propagation

In [1] presented results of a study group delay (GD) ripple in a no uniform transmission lines. These results suggest that at frequencies corresponding to the minimum VSWR at the input of the transmission line, reaches a maximum GD , and peak frequency VSWR reaches a minimum GD . At the same time marked by a paradoxical situation – in the bands in the minimum GD ripple group electromagnetic propagation time can be more than the speed of light in vacuum at finite insertion loss of the electromagnetic wave. This article shows the relationship of the group velocity and the values of the coefficient of reflection from irregularities in the transmission line, which is confirmed by the results of measurements. These data imply that in the limit group velocity can be infinitely large, but and the insertion loss in the propagation of electromagnetic waves infinitely large. But there are also intermediate options that are confirmed experimentally. This effect indicates the possibility that in the inhomogeneous line signal can be transmitted with the rate over the speed of light propagation.

group delay, non-uniform transmission line, superluminal signal propagation