Design of a 330-GHz Frequency-Tunable Gyrotron With a Prebunched Circuit

The design of a 330-GHz second harmonic gyrotron with broadband tunability is presented in this article. Loaded with a prebunched cavity, the output power is almost doubled (~216 W, corresponding to the output efficiency of 3.6%) compared with a conventional open-cavity scheme, and the tuning range is ~1.85 GHz. To further reveal the feasibility of the prebunching section for the harmonic operations, it is theoretically demonstrated that the phase shift inside the prebunching Section plays an important role in improving the interaction performance. The dependence of the phase shift on the cavity dimension and propagation constant is explored, which instructs the circuit optimization. Moreover, the engineering designs of the magnetron injection gun, the output window, and the collector are presented under a 10-T super-conducting magnet. The overall configuration of the tube is exhibited at the end of the article.