Analytical method of spiral line

A theoretical analysis of a spiral line based on electromagnetic field theory is attempted. The interdifferential equations that must be satisfied by the voltage and current on the line are derived from electromagnetic theory. When these equations are modified so that the general telegraphic equations are satisfied, the series impedance and the parallel admittance resulting from the primary constants are given by the integrals on the current distributions. These parameters are used in deriving the nonuniform distributed constants for each mode of assumed forward and backward traveling waves, and the propagation characteristics of the spiral line are obtained.