Title :
High power X-band helix TWT for airborne radar applications
Author :
Dionisio, R. ; Andriolo, G.
Author_Institution :
Microwave Tubes R&D Dept., Alelco S.p.A, Palermo, Italy
Abstract :
A PPM-focused, X-band, pulsed helix TWT for airborne radar applications has been designed. The main requirements for this tube are a minimum output power of 8 kW peak with 5% duty cycle over a 10% bandwidth with an efficiency of 30%. The requirements for high average power and efficiency dictate the selection of the design parameters. The electron beam is focused with samarium cobalt periodic permanent magnets and a shadowed control grid allows fast modulation. The rf interaction structure consists of a wound helix supported by three APBN rods inside the vacuum envelope. It comprises two amplifying sections separated by a sever section. The PPM magnetic structure is optimised in order to reduce dimensions and weight at the required focusing axial magnetic field level of about 2800 Gauss. A two stage depressed collector is used to obtain the required overall efficiency.
Keywords :
airborne radar; electron beam focusing; permanent magnets; travelling wave tubes; 2800 G; 30 percent; 8 kW; APBN rods; Sm-Co periodic permanent magnets; SmCo; airborne radar applications; amplifying sections; design parameters; duty cycle; electron beam focusing; fast modulation; focusing axial magnetic field; high power X-band helix TWT; minimum output power; overall efficiency; rf interaction structure; sever section; shadowed control grid; two stage depressed collector; vacuum envelope; Airborne radar; Bandwidth; Cobalt; Electron beams; Magnetic modulators; Optical modulation; Permanent magnets; Power generation; Samarium; Wounds;
Conference_Titel :
Vacuum Electronics Conference, 2002. IVEC 2002. Third IEEE International
Print_ISBN :
0-7803-7256-5
DOI :
10.1109/IVELEC.2002.999421
