Electromagnetic Field Distribution in Matched Intervals of Periodically-irregular Waveguides for Gyrotrons

In this paper, T-functions technique and finite element method numerical experiments were provided for TE_0i modes of matched intervals of periodically-irregular waveguides with the account of cut-off modes. The forward and backward wave components interaction, as well as modes conversion, causes complex spatial distribution of the waves. The considered variants specify that the distributions do not match a second-order periodic condition as it was considered earlier. In all considered variants the waveguide intervals are impedance matched at the end sections