Nonstationary electromagnetic field propagation in dielectric waveguide
The paper considers a method for analysis of arbitrary pulse signal propagation in an open dielectric waveguide. The method is based on presenting the sought fields as an expansion over continuous spectrum of some frequency independent modes that are built in a way to account for the boundary conditions at the transverse dielectric inhomogeneity and at the infinity. A pulse wave excitation and propagation in a circular dielectric waveguide has been calculated and analyzed using the presented method. The transient processes occurring in this case have been investigated. It was demonstrated that a precursor in such a waveguide is propagated as a surface pulse wave and an accompanying Cherenkov’s radiation cone inside the dielectric core, the longitudinal propagation speed of which being equal to the speed of light in the surrounding medium.