Analysis of TEM mode on a curved coaxial transmission line

Through the use of a perturbation approach, explicit expressions are derived for the changes in the electromagnetic field structure that occur when a transverse electromagnetic (TEM) mode on a coaxial transmission line enters a bend in the line. All of these changes are evaluated to at least first order in the inverse of the radius of curvature of the first nonvanishing correction term of the propagation constant (which is found to be of second order). Graphical results for the variation of the propagation constant as a function of curvature and other parameters characteristic of the coaxial line are presented