Using Controlling Chaos Technique to Suppress Self-Modulation in a Delayed Feedback Traveling Wave Tube Oscillator

Summary form only given. Traveling wave tubes (TWTs) are widely used in communication and radar systems. Recently microfabricated folded waveguide TWT oscillators with external delayed feedback were considered as promising sources of microwave radiation in millimeter and THz band. However such a device is inclined to self modulation instability that result in generation of multiple frequency or spread-spectrum chaotic signal. In this paper we present a method for suppress self-modulation in a delayed-feedback TWT based on controlling chaos technique. One of the most famous methods for chaos control is the method of time-delayed autosynchronization suggested by K. Piragas (1992). This method allows stabilization of an unstable periodic orbit by adding an external feedback with delay time equal of the period of motion to be stabilized. We have developed a modification of the Pyragas´ method for a delayed feedback TWT oscillator. The method is based on splitting the feedback loop into two paths with properly chosen delays and magnitudes. In contrast with a classical Pyragas method it allows control of high-frequency oscillations. The numerical simulation confirms that the suggested method provides suppression of self-modulation and enhances the domain of stable single-frequency generation. Moreover, for some choice of feedback parameters application of the controller increases output power and efficiency.