Waveguiding and Resonant Cylindrical Structures with Time-Varying Permittivity

This paper presents the analytic results of comparison of electromagnetic field transformation in 2D circular resonator and cylindrical waveguide due to time discontinuity in permittivity. The basic interest is to gain insight into details of the electromagnetic field evolution during the transient period and to reveal the common features and distinctive ones that underlie these phenomena. "Time transmitted" and "time reflected" electromagnetic fields of the structures are considered. Possibility of transformation of guided modes into radiated one in a waveguide is considered.