Experimental demonstration of multi-frequency-band frequency tunability with Gyrotron FU CW XA

Frequency tunability in multi frequency bands was experimentally demonstrated in Gyrotron FU CW XA. Frequency tunable modes were searched for with measurement of the radiation pattern outside the vacuum window of the gyrotron with no mode converter. The frequency variation is due to the gyro-BWO mechanism and the same radiation pattern is kept within a finite range of the magnetic field for each oscillation mode. Five transverse modes showing the frequency variation more than 1 GHz were obtained.