Application of harmonic perturbations to the calculation of periodically corrugated waveguides

Harmonic perturbation of the profile of an infinite axisymmetric periodically-corrugated waveguide is used for the calculation of its electrodynamic characteristics. The analysis is based on the method of Fredholm-type integral equations of the second kind. The problem is solved analytically for the perturbation of a cylindrical waveguide. These analytical results serve as the basis for the solution of the inverse problem of recovery of the waveguide profile from the given dispersion curve.