基于馈线结构，分析了影响馈线带宽特性的两个关键因素--谐振和高次模。通过测量馈线的时域阻抗和脉冲频谱范围内的S参数，详细研究了它们的影响并进行了实验验证，测试结果表明: 馈线周期性阻抗不均匀经傅里叶变换可分解成两个谐波分量，它们导致电压驻波比曲线出现谐振峰。馈线不连续结构激励出TE11和TE21高次模，它们在传输损耗曲线上引起损耗峰。馈线-3 dB带宽由一次谐波分量产生的谐振峰决定，但仍能匹配脉冲频谱的主瓣宽度。最后，根据测试结果，对馈线后续优化设计提出了相应的改进措施。

Based on structures in feeder line, two critical factors including resonance and higher mode, which affect bandwidth characteristics of feeder line, are analyzed. By measuring time-domain impedance and S parameters over the range of pulse frequency spectrum, their effect are studied in detail and validated experimentally. The testing results indicate that periodic impedance non-uniformity of feeder line is processed by Fourier transform and can be decomposed into two harmonic components which lead to resonance peaks on voltage standing wave ratio curve. The discontinuous structures in feeder line can excite TE11 and TE21 higher modes which cause loss peaks on transmission loss curve. The -3 dB bandwidth of feeder line is determined by resonance peak that the first harmonic component generates, but it can still match the main lobe width of pulse frequency spectrum. Finally, according to test results, the corresponding improvement measures are put forward to subsequent design optimization of feeder line.