Nonlinear signal suppression in a traveling wave tube

The results of an experimental and theoretical study of the passage of monochromatic and pulse-modulated microwave signal through a traveling wave tube operating in the nonlinear suppression mode are presented. It was found that the TWT can operate either as a saturable absorber or as a power limiter and these regimes depend on the magnitude of the accelerating voltage and beam current. In the first case, the maximum signal suppression level corresponding to the Kompfner dip is realized in the linear mode, and in the second case - in the nonlinear mode, at a certain input signal power. It is shown that in the case of maximum suppression, a short pulse is formed at the front of the radio pulses. In the nonlinear Kompfner dip mode, the duration of such pulse is decreased with an increase in the power of the input radio pulse. The simulation results obtained using the nonlinear nonstationary theory of a traveling wave tube are in good qualitative agreement with the experimental data.