Method of Coupled Waves in the Theory of Excitation of Waveguides by High-Frequency Currents with Slowly Varying Amplitudes

Abstract

Based on the method of coupled waves, we propose nonstationary equations describing excitation of waveguides in which the energy distribution in wave packets varies due to mutual transformation of the coupled waves. We obtain a universal expression relating the dispersion of a waveguide mode to the frequency dependence of its field, i.e., to a change in the field structure of the mode during a pulse. To illustrate the proposed procedure of constructing nonstationary equations, we apply it to the well-known case of excitation of plane-wave packets by electric currents in a homogeneous isotropic medium with time dispersion.