Phase locking of an S-band wide-gap klystron amplifier with high power injection driven by a relativistic backward wave oscillator

Abstract

Theoretical analyses and preliminary experiments on the phase-locking characteristics of an inductively loaded 2-cavity wide-gap klystron amplifier (WKA) with high power injection driven by a GW-class relativistic backward wave oscillator (RBWO) are presented. Electric power of the amplifier and oscillator is supplied by a single accelerator being capable of producing dual electron beams. The well phase-locking effect of the RBWO-WKA system requires the oscillator have good frequency reproducibility and stability from pulse to pulse. Thus, the main switch of the accelerator is externally triggered to stabilize the diode voltage and then the working frequency. In the experiment, frequency of the WKA is linearly locked by the RBWO. With a diode voltage of 530 kV and an input power of ∼22 MW, an output power of ∼230 MW with the power gain of ∼10.2 dB is obtained from the WKA. As the main switch is triggered, the relative phase difference between the RBWO and the WKA is less than ±15° in a single shot, and phase jitter of ±11° is obtained within a series of shots with duration of about 40 ns.

Injection locking of a two-mode electron oscillator with close frequencies

“…The problem of a high-power multimode electron oscillator injection locking by an external driving signal has attracted a considerable interest. The injection locking allows for controlling the radiation frequency and phase of high-power microwave sources, [1][2][3][4][5] as well as reducing transient times. 5,6 Also, a low-power external driving of a high-power oscillator may result in the fast frequency step tuning owing to the mode switching effect.…”