Radio pulse propagation in a smoothly bent oversized waveguide

An efficient method to calculate EM pulse dynamics in a wide nonuniform waveguide is proposed. Fourier transformation of the adiabatic approximation into time domain results in a series of traveling pulsed modes whose group velocities depend on the mode number, waveguide cross section and axis curvature. Parabolic equation can be used for numerical implementation of the asymptotic solution.