Design Study of Two-Plane Focusing Periodically Cusped Magnets for a 300 GHz Sheet Beam Traveling-Wave Tube

A sheet electron beam is an effective means to increase efficiency of traveling-wave tubes (TWTs). It is known that periodically cusped magnets (PCMs) can stably confine sheet electron beams. Also, PCMs have small volume, so the overall system can be portable. In this work, the magnetic field of PCMs are optimized for a 300 GHz sheet beam TWT. Simulations are done using Warp and CST Particle Studio. Numerical studies show that with peak magnetic field of 0.4 T and period of 3 mm, a sheet beam with size of 0.32 mm * 0.06 mm can stably propagate up to 30 mm.