A new coupled-cavity circuit for high mean power traveling-wave tubes

A technique to increase the mean power capability of coupled-cavity traveling-wave tubes (TWTs) was demonstrated theoretically and practically. Theoretical work involved the investigation of the RF and thermal properties of the structures using experimental and computing techniques. A description is presented of the testing of, and results from, an experimental I-band coupled-cavity TWT containing the novel ferrule bar and ring structure operating at an output power of 50-kW peak, 3-kW mean. A threefold increase in mean power over an existing coupled-cavity TWT, with no degradation in the percentage bandwidth, has been obtained. The extension of this technique to other frequency bands is also discussed.