Research Progress of a Second Harmonic Gyrotron

A scheme of a second harmonic gyrotron operating in CW regime is presented. This tube is designed to provide output power about several tens of watts at 330 GHz. - Whispering-gallery mode is selected as the operating mode. The performance of the candidate TE82 and $\mathbf{TE}_{\pmb{92}}$ mode is evaluated by nonlinear code. It is confirmed that TE92 mode can suppress the competing modes successfully. The fabricating key components of this tube is presented.