A mode-selective circuit for TE01 gyrotron backward-wave oscillator with wide-tuning range

This study proposes a mode-selective circuit to suppress the competing modes in a TE
₀₁
gyrotron backward-wave oscillator (gyro-BWO). The circuit, also functioning as an interaction structure, comprises of several transverse slices. It eliminates the restrictions of the mode-competitions and allows a longer interaction structure to optimize interacting efficiency. Mode-selective effect will be analyzed. Experimental results indicate that the Ka-band TE
₀₁
fundamental harmonic gyro-BWO is capable of continuous tuning from 31.4 GHz to 36.4 GHz with a peak efficiency of 23.7% corresponding to 100 kW at I
_b
= 4.5 A and V
_b
= 93.6 kV.