Experimental Investigations on a Frequency-Tunable Gyrotron With Multiband Radiation

A frequency-tunable gyrotron with multi-band radiation has been designed, manufactured, and investigated experimentally. The frequency tuning scheme utilizing transverse modes switching and axial mode transition is employed to obtain multiband radiation. Three modes TE02, TE43, and TE24 are excited successively with the increase of the magnetic field. The main operating frequency of these modes are 140, 250, and 263 GHz, respectively. Experimental results indicate that a certain frequency-tuning range can be obtained at each frequency band by means of exciting a series of high-order axial modes.