The theoretical analysis of abrupt structure loaded with lossy material on both sides has been described.Dispersion equations of waveguides and field matching equations of hybrid modes (HEM) for abrupt structures with absorber are derived.Further
numerical solution of the equations has been used to analyze the field of different modes in each region and study the properties of waveguides and abrupt cavities loaded with lossy material.The theoretical analysis and calculation code are used to design and study the low Q cavities for gyroklystrons.