Reduction of noise factor in TWT with a convergent electron beam

This article describes the results of the work on reducing the noise factor submitted by means of choice the parameters of EOS for broadband traveling wave tube (TWT) with output level 100 W. For reduction the noise factor in this TWT has been increased at a sacrifice of the diameter of the cathode. Thus the amplitude of the magnetic field necessary for focusing the beam of a former has decreased. If P_input is greater than zero (P_input - output power), a noticeable dynamic defocusing took place (body current is greater than 10 mA). The dynamic defocusing has been suppressed due to the 1,2 times increase of the magnetic field at the end of the interaction space. The amplitude of the magnetic field was calculated. If the output power is equal to zero, the body current and the noise factor have not increased.