The purpose of this study is the observation of coherent resonance phenomenon in two microwave single-mode chaos generators with a delayed feedback under external noise influence. The first generator is a vacuum chaos generator based on a traveling wave tube and a multi-resonator drift klystron. The second generator is a solid-state chaos generator based on a transistor amplifier and a spin-wave transmission line supporting a magnetostatic surface wave (MSSW) propagation. The chaotic dynamics of the vacuum generator is caused by the presence of a falling section on the amplitude characteristic of the drift klystron. In the solid-state generator, the development of chaotic dynamics is associated with a nonlinear parametric three-wave decay of the MSSW into short-wave spin waves.

Methods. To observe the coherent resonance phenomenon in single chaotic oscillators (the microwave chaos generators), the time filtering method under the noise influence with a limited frequency band is used. The method is based on the effect of forced chaos synchronization (through its suppression) by external noise. The proposed method has the greatest efficiency in frequency separation of the power spectra of chaotic and noise signals (the power spectra of both signals should not overlap).

Results. In the studied microwave chaos generators of various physical natures, the existence of the “on-off” intermittency mode, in that the coherent resonance phenomenon is observed, has been experimentally established. It has been shown that the autocorrelation time of the envelope of a chaotic MW signal has a maximum value at a certain power level of the noise MW signal, and this maximum value depends on the noise MW signal bandwidth.

Conclusion. The developed method for the coherent resonance observation can also be applied to the multimode (broadband) ring chaos generators with the delayed feedback.