Design considerations for linear beam devices employing emittance dominated electron beams

As the frequency of linear beam RF device operation increases, the effect of beam emittance starts to play a more crucial role in the design of real world devices. Several issues related to TWT design in particular have been addressed for devices employing field emitter cathodes through W-Band frequencies. The general formulation is also applicable to emittance dominated thermionic beams operating in the submillimeter and THz regimes.