Dispersion analysis and mode suppression of confocal waveguide for gyro-TWT

Theoretical analysis of a broad bandwidth confocal waveguide for W-Band gyro-TWT is presented. This waveguide effectively suppresses the undesired modes, and therefore has extremely low mode density. Stable single-mode, broad bandwidth operation is achieved in the HE
0,6
mode. The confocal waveguide could be used in high-power gyro-TWT, which can provide greater operating stability and bandwidth, especially in an overmoded waveguide structure.