Synthesis of folded waveguide TWT

Abstract

The folded waveguide traveling-wave tube (FWTWT) has the advantage of higher power capability, with reasonable bandwidth, compared with helix TWT and coupled-cavity TWT. The method of synthesizing the main parameters of FWTWT is studied and used for designing Ka-band devices. To verify the synthesis, the results are compared with those generated by simulation codes such as HFSS and three-dimensional particle-in-cell (PIC) code for the estimation of cold and hot characteristics. From the synthesis, based on Pierce's small signal theory, it is shown that plasma frequency sensitivity affects the growth rate. A Ka-band folded waveguide TWT has been designed from the synthesis and is under fabrication. Theoretical and experimental details are presented.