π-Line high power TWT´s

The π-line slow-wave structure (SWS) may be used in high power pulsed S-band or C-band TWTs, delivering peak output power levels from 100 kW to about 1 MW. The average power delivered by such tubes is between 1 kW and 25 kW. The hot band is about 12-15%, with a minimum interaction efficiency of 20% in the band, reaching 35% in the band center, thanks to an original velocity taper. An interesting property of this SWS is the quasi-absence of "rabbit ears" (spurious oscillations on the leading and trailing edges of the HV pulse) when the tube is cathode modulated. Several π-line TWTs are already used in European military radars with this type of modulation.