WIDEBAND TRAVELLING-WAVE TUBE Russian patent published in 2013 - IPC H01J25/00 

FIELD: physics.

SUBSTANCE: wideband travelling-wave tube (TWT) has a spiral slow-wave structure whose output section has a screen with longitudinally conducting metal fins, the gap between which and the spiral (not less than twice) increases gradually or in steps towards the end of the slow-wave structure. The length of the section of the slow-wave structure with the increasing gap can range from 20 to 100% of the clean (free from absorbent) section of the output section of the slow-wave structure. The maximum size of the gap between fins of the screen and the spiral can be not less than twice the minimum size of the gap which corresponds to the beginning of the section and can reach a size which corresponds to absence of fins. Increasing the gap increases phase velocity and coupling impedance. Varying these values according to a given law along the length of the spiral slow-wave structure enables to obtain improved characteristics of the travelling-wave tube. Simultaneous variation of the spacing of the slow-wave structure with the varying gap enables to further improve parameters of the travelling-wave tube.

EFFECT: low level of the second harmonic, high resistance to self-excitation on the return wave and high electronic efficiency of interaction of wideband travelling-wave tubes with a spiral slow-wave structure.

4 cl, 2 dwg