turkmath.org

New effects of nonlinear excitation of active GHz devices (specifically, Gunn diodes) will be presented that have been studied through computer simulations of extended microwave circuits (series or parallel networks of transmission lines with active devices) under the conditions of time-delay feedback. Formulations of problems and approaches to their solutions will be discussed for a few cases of microwave networks. New kinds of oscillations will be considered that emerge due to time-delay coupling, e.g., multi-frequency excitation, short-pulse generation, broadband dynamical chaos. Specific properties will be discussed such as conditions for non-conventional regimes of oscillations, generation of trains of high-frequency pulses, hysteresis and bistability of switching and excitation.