Compact and Efficient Output Converter for Gyrotron Mode with High Longitudinal Wave Number

This paper presents an external quasi-optical converter for a 28 GHz 20 kW continuous wave gyrotron with TE
1,2
operating mode. The gyrotron has a big output diameter, which leads to a small Brillouin angle of the output mode. The converter changes the angular spectrum of the radiation already in the first element of the converter — the waveguide emitter. Along the way, in the same emitter, the electromagnetic field is grouped into a highly efficient Gaussian beam ready for further transportation. The proposed design allowed to reduce the converter length approximately three times and has efficiency over 97%.