Design and Experiment of a 200-kW Q-Band Gyro-TWT

In this article, the design and experimental verification of a 200-kW ${Q}$ -band gyrotron traveling wave tube (gyro-TWT) amplifier are presented. A low-velocity spread magnetic injection electron gun (MIG), a new type of multichannel TE₀₁ mode input coupler, and a broadband double-disk output window are adopted in the design to improve the performance of the gyro-TWT. At the same time, the lossy ceramic ring-loaded high-frequency interaction circuit is constructed to provide the required loss for stable operation, and the potential oscillations are effectively suppressed. Saturated peak power of 208 kW and 12.5-kW average output power are measured at 47 GHz by hot test, corresponding to a saturated gain of 50.2 dB, an efficiency of 29.4%, and a −3-dB bandwidth of 5.5 GHz.