Design of a system converting an output radiation of frequency tunable gyrotron into a gaussian beam

A novel design of a versatile quasi-optical system for conversion of gyrotr on radiation into collimated gaussian beams is presented and discussed. The proposed system consists of a quasi-optical antenna, two ellipsoidal mirro rs and a spatial filter which truncates the sidelobe radiation. The system is appropriate as a transmission line for frequency tunable gyrotrons opera ting at TE0n and TE1n modes. As an illustration of our approach, we present results which demonstrate the applicability of the developed system for co nversion of the radiation generated by the Gyrotron FU IVA. The examples in clude conversion of four TE1n mode outputs (TE12, 170 GHz; TE13, 271 GHz; T E14, 372 GHz; TE15, 472 GHz) into gaussian-like beams and three TE0n modes (TE02, 223 GHz; TE03, 323 GHz; TE04, 423 GHz) into bigaussian-like beams.