通过分析行波管螺旋导电面模型中的电磁场,给出了色散和耦合阻抗计算公式,并深入研究了非线性理论中的空间电荷降低因子.结果表明,螺旋导电面模型相对理想导电圆筒中的空间电荷降低因子在较高频段变化不大.空间电荷降低因子的变化反映了螺旋线外电磁场对电子注的作用,同样的慢波结构,较高频率的电磁场应有较大的影响.因此,使用螺旋导电面模型在较高频段计算空间电荷降低因子是不合适的. By analyzing the electromagnetic field in the TWT model, the formulas of dispersion and coupling impedance are given, and the space charge reduction factor in the nonlinear theory is studied. The results show that the spiral conductor surface model The space charge reduction factor does not vary much at higher frequencies. The change of space charge reduction factor reflects the effect of the electromagnetic field outside the spiral on the electron injection, and the same slow-wave structure and higher frequency electromagnetic field should have a greater impact.Therefore, Calculating the space charge reduction factor in the higher frequency band using the spiral conductive surface model is not suitable.