Effects of beam tunnel on 220GHz rectangular beam folded Waveguide Traveling Wave Tubes

A novel rectangular beam folded waveguide traveling wave tube (RBFWG-TWT) was proposed for higher output power. In this paper, effects of beam tunnel on transmission properties was studied to investigate the proper size to prevent electromagnetic wave leaking from the electron port. Then a RBFWG-TWT operating at 220GHz was simulated by the Particle-in-cell (PIC). To obtain the optimized aspect ratio of the electron beam and beam tunnel, influence of broad and narrow sides on output power was also simulated and analyzed.