Non-monochromatic fields in a dispersive electrodynamic line. I. the discrete approximation [microwave tubes]

Simulations of signal spectra in microwave tubes are topical, e.g., because of the EMC problem or development of digital telecommunications, where radio pulses are short and signals are wideband. One of stages of the spectral method is the time domain evaluation of arbitrary non-harmonic fields in a dispersive electrodynamic line with an electron beam (this might be a delay structure for TWTs and CFDs or smoothbore waveguide for fast wave devices). The FDTD and FETD methods are the most appropriate, but they are too computationally intensive. Instead, the variable separation method may be used. This paper outlines this method and its application to the analysis of microwave tubes.