Experimental Observation of Frequency Locking and Noise Reduction in a Self-Injection-Locked Magnetron

We report an experimental observation of frequency locking and noise reduction in a self-injection-locked magnetron oscillator operating at 2.455 GHz. Part of the magnetron output signal is injected into the magnetron through a feedback loop to lock the oscillation frequency. A frequency-tunable high- cavity is placed in the feedback loop to tune the locked frequency. Experimental results show a noise reduction by more than 13 dB at 1 MHz offset and a frequency tuning bandwidth of 0.12% at a center frequency of 2.455 GHz.