High power S-band traveling-wave tube

The design and performance characteristics of a prototype high power, coupled-cavity traveling-wave tube are described. The tube incorporates periodic permanent magnet focusing and a "shadow-grid" electron gun. It provides greater than 125 kW of peak output power at six percent duty cycle over the frequency range 3.1 to 3.5 GHz with 50 dB of gain. Up to 10.5 kW of average output power has been demonstrated. This represents the highest average power that has been obtained from a PPM focused tube of this type. This outstanding performance is a result of excellent electron gun and magnetic focusing structure design in conjunction with a novel liquid cooling technique that passes the coolant close to the circuit drift tubes. Mechanical features, electrical design parameters and detailed operating data will be presented.