实验研究发现，射频滤波器在连续波和超宽带脉冲条件下其带外传输性能基本一致，但在带内某些频段，超宽带脉冲环境下滤波器的传递函数远大于1。此外，滤波器在超宽带脉冲下的时域响应还出现了脉冲振荡特征。针对这些现象，从滤波器的非线性无源互调和Q值效应的两个方面，分析了滤波器在超宽带脉冲作用下的响应机理，初步解释了上述现象。此外，通过不同辐射场强下的测量结果可知，滤波器无源互调还出现了非线性现象，使得测量结果的普适性受到一定限制。基于传递函数的预测结果表明，连续波测量结果的预测波形无论是从能量上还是从峰值功率上都明显小于实测结果。这些都反映出，滤波器在超宽带脉冲环境下的响应机理与在连续波环境下的响应机理明显不同，其预测结果也差异较大。也就是说，连续波测量结果不可用于超宽带脉冲的效应分析和评估。

The experiments reveal, for the RF filter, the out-off-band transfer property under ultra wide band (UWB) pulses is essentially in agreement with that of continous wave (CW). However, for some frequencies in the in-band of the filter, the transfer function of UWB is much larger than 1. Moreover, the oscillating property is found in the time domain response of the filter. Therefore, based on the nonlinear passive intermodulation (PIM) and the Q-value, the response mechanisms of the filter are studied. The PIM of the filter shows nonlinear effects under the two different field strengths, which results in the limited universality of measurement results. Furthermore, the signal through the filter is predicted by making use of the two measured transfer functions. The predicting results under CW pulse are smaller than the measured ones in energy and peak power. In a word the response mechanisms of the filter under UWB pulse does differ from the that under CW pulse, i. e., the measured results of CW can’t be applied for the UWB effect analysis and evaluation.