Magnetic circuit for a sheet electron beam Ka-band microfabricated traveling wave tube

Abstract

A magnetic circuit for a sheet beam Ka-band microfabricated traveling wave tube (TWT) is presented in this paper. The magnetic circuit is designed to provide a uniform solenoidal magnetic field to keep the sheet beam focused. The design of the magnetic circuit has been optimized using the CST EM STUDIO. Neodymium Magnets and Consumet® Electronic Iron have been selected as the materials of magnets and pole pieces in this design, respectively. Simulation results are presented in the form of 3-d vector magnetic field plots. The results show that the magnetic circuit can produce a uniform magnetic field of 0.21 T over a distance of 40 mm. To assemble the magnetic circuit, an aluminum fixture is designed and fabricated to hold the magnets and pole pieces together. Measured results show an excellent match with the simulation results.