Title :
Coupled cavities by rods (TWTs)
Author :
Busacca, G. ; Muratore, A. ; Zanforlin, L.
Author_Institution :
Selenia SpA, Palermo, Italy
Abstract :
The average power capability of conventional coupled cavity TWTs (traveling-wave tubes) is limited by the maximum amount of heat transfer from the ferrules to the cooling walls. An unconventional structure, allowing a remarkable improvement in the thermal capability of such tubes, is proposed. It operates in the fundamental backward wave mode. The structure uses two conducting rods: one rod connects alternate pole pieces and the other connects the other pole pieces. Heat transfer capability is improved because of the small dimensions of coupling holes compared to the kidney iris. A preliminary thermal analysis showed that the maximum temperature of the ferrules was decreased by 50-70 degrees C against the more conventional structure (X-band 1.5-kW average power TWT). The performance of an eight-cavity experimental structure is in good agreement with the equivalent model studied; 10% bandwidth and 700-W minimum interaction impedance have been obtained.<>
Keywords :
backward wave tubes; heat transfer; thermal analysis; travelling-wave-tubes; alternate pole pieces; conventional coupled cavity TWTs; coupling holes; eight-cavity experimental structure; equivalent model; fundamental backward wave mode; heat transfer; kidney iris; minimum interaction impedance; thermal analysis; two conducting rods; Capacitance; Coupling circuits; Equivalent circuits; Heat transfer; Impedance; Periodic structures; RLC circuits; Resonance; Resonant frequency; Structural rods;
Conference_Titel :
Electron Devices Meeting, 1989. IEDM '89. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-0817-4
DOI :
10.1109/IEDM.1989.74261
