分析和计算了互作用区折叠波导截面长宽比(b/a)、直边高度和电子束通道大小等结构参数对太赫兹波段折叠波导行波管工作性能的影响。结果表明：互作用区衰减常数随b/a的增大而减小,耦合阻抗和小信号增益则随b/a的增大先增加而后减小,存在最优值。电子束通道越大,衰减常数越大,耦合阻抗和小信号增益降低得越多。相对于电子束通道,增益和损耗对直边高度的敏感程度显著降低。因此为了提高器件功率容量,可适当增加折叠波导的高度；在保证电子束能够顺利传输的前提下,电子束通道越小越好。在折叠波导行波管的实际研制中,可依据具体的实验条件和要求,在适当的范围内合理选取互作用区各结构参数的值。

Effects of the structure parameters, including the ratio of b/a, the height of the folded waveguide, the width of the beam tunnel, on the output characteristics of the terahertz band folded waveguide traveling wave tube are analyzed. Calculation results show that there exists an optimal value of b/a for the maximum small signal gain and the coupling impedance. With the increasing of the width of the beam tunnel, the attenuation constant will increase markedly. Thus the small signal gain and the coupling impedance will decreased markedly. Both the attenuation constant and the small signal gain are relatively insensitive to the height of the folded waveguide. The results are useful to the design of the folded waveguide tube in practical applications.