Development of the calculation technique of the three-electrode electron gun modulation characteristic of the microwave devices

The present paper concerns the modulation characteristic calculation technique development for the three-electrode electron gun. This technique is based on the analysis of the field structure made by different focusing potentials along the electron-optical system axis, which was conducted with the finite integration technique. The obtained permeability values of the first anode allowed calculating the modulation characteristic, which defines the type of the cathode emission current in dependence of the focusing potentials in the minor values region.