A. A. Skvortsov

Interest to electrodynamic parameters of rectangular waveguides with one (RTSW) and two (RDTSW) T-ridges and dielectric cylinder in capacitance gap is conditioned by the fact that considered structures are prototypes in design of microwave devices for thermal processing of dielectric materials. Determination of cutoff wavelength of the dominant wave of structures under consideration is an important task arising in design of microwave devices on the basis of pieces of RTSW and RDTSW with such dielectric filling of capacitance gap. Quasi-analytical (approximate analytical) calculation of cutoff wavelength of the dominant mode of RTSW and RDTSW with dielectric cylinder in capacitance gap is carried out by means of replacing the piece of waveguides under study with unit length by equivalent network in the form of resonance circuit with lumped inductance and capacitance. Parameters of equivalent network for calculation of the cutoff wavelength of the dominant mode of waveguides under consideration are determined taking into account results obtained earlier. In order to confirm the efficiency of technique considered in present work, results of calculations of normalized cutoff wavelength of the dominant mode of RTSW and RDTSW with dielectric cylinder in capacitance gap performed by the equivalent networks method (ENM) and the finite element method are compared. Comparison has shown quite good agreement of both approaches. So, application of ENM has allowed establishing a simple quasi-analytical dependence in an explicit form of cutoff wavelength of the dominant mode of RTSW and RDTSW with dielectric cylinder in capacitance gap upon sizes of the cross section and electrophysical parameters of dielectric filling of capacitance gap providing sufficient accuracy of calculation for engineering practice in designing microwave devices for thermal processing of dielectric materials on the basis of pieces of structures under study.