Large-Signal 2-D Modeling of Folded-Waveguide Traveling Wave Tubes

A new computationally efficient 2-D large-signal code TESLA-FW has been developed to model traveling wave tubes (TWTs) using folded (or serpentine) waveguide (FW) slow-wave structures. The code incorporates a recently published shunt-loaded transmission line model of the structure and takes advantage of a new time advance algorithm recently implemented in the code TESLA-CC. The new code has been applied to modeling G -band (220 GHz) serpentine and FW TWTs. Results compare very favorably with those obtained from the 3-D particle-in-cell (PIC) code MAGIC3D and with experimental data. Typical running times of TESLA-FW are 1-2 orders of magnitude less than those of 3-D PIC codes.