Transmission line parameters of video delay lines

The paper investigates the applicability of transmission line concepts to the axially symmetric waves that travel along a coil screened by a coaxial outer conductor. Both the inductance per unit length and capacitance per unit length are frequency dependent and require special definitions to comply with the dispersion relation of the waves. A novel quantity, termed the series capacitance parameter (in Fm) is derived from the electromagnetic theory which models the helix with an anisotropic current carrying sheet. The parameter is related to the radii of coil and screen, and the dielectric constants of the materials interior and exterior to the coil. The theory confirms the value of this parameter previously obtained from experiment.