Effect of Free-running Magnetron Spectrum on Injection-locking Bandwidth
The output signal of a free-running magnetron usually has a certain bandwidth,rather than an ideal single frequency signal.The effect of the spectrum of a free-running magnetron on injection loc-king is studied.Statistically,it is believed that the output frequency of a free-running magnetron follows a normal distribution.Combined with injection locking theory,the output spectrum of the magnetron at dif-ferent injection frequencies is calculated.Theoretical analysis shows that when considering the output spectrum of a free-running magnetron with a certain bandwidth,the bandwidth of peak frequency variation will be greater than the locking bandwidth under the ideal single frequency assumption.As the free-run-ning bandwidth increases,the bandwidth of peak frequency variation increases and the locking bandwidth decreases.The experimental results of magnetron injection locking show that when the free-running band-width(3dB)is 0.375 MHz and 1.049 MHz,the locking bandwidth is 8.4 MHz and 7.9 MHz,and the bandwidth of peak frequency variation is 10.2 MHz and 13.9 MHz,respectively,which verifies the cor-rectness of the theory.This study develops the magnetron injection locking theory.