A High-Power Periodically Focused Traveling-Wave Tube

The design considerations, construction, and performance of an S-band, pulsed, kilowatt-level traveling-wave tube, focused by means of periodic permanent magnets are described. The tube exhibits saturated power gain in excess of 30 db, with a bandwidth of approximately 2-4 kmc and weighs 17 pounds or less, complete with package. The results of studies on the electron beam defocusing effect of strong rf fields and on the effect of attenuator design on power buildup and saturation level are reported. Factors affecting the design of a high-power traveling-wave tube using periodic magnetic focusing are described in order to show the design constraints imposed by the periodic focusing system.