Experimental study of a Q-band gyro-TWT

The experimental study of a Q-band gyrotron-travelling-wave tube (gyro-TWT) amplifier operating in the circular TE
₀₁
mode at fundamental cyclotron harmonic is presented. A periodic dielectric loaded structure is adopted in the interaction circuit of the gyro-TWT to suppress spurious modes TE
₁₁
and TE
₂₁
. A saturated peak power of 175 kW is obtained corresponding to saturated gain of 53 dB and an efficiency of 38% with -3dB bandwidth of 3 GHz(~7%). The gyro-TWT is found to be zero-drive stable at these operating points.