Excitation of the chaotic oscillations in millimeter BWO

In the paper the characteristic properties of the chaotic oscillation excitation in millimeter Backward-Wave Oscillators are investigated. To enhance the interaction efficiency and provide the strong nonlinear working regimes of the oscillator the weak-resonant oscillatory system with large electrical length is proposed to use. It is shown, that in this case the oscillation automodulation with complicated power spectrum are developed for the smaller values of the working current to starting current ratio in comparison with BWO having matched oscillatory system. This allows to oscillate with high efficiency the continuous millimeter chaotic (noise) signals which have a wide enough power spectrum and integral power of about several watts.