介绍了一种电气绝缘柔软复合材料--DMD膜，通过对膜结构的分析，设计了一种串联等效电路模型对其进行分析。运用该模型，对DMD膜在浸渍前和浸渍后两种情况下的介电常数和介电强度进行了求解并给出计算公式。从公式可以看出: DMD膜的介电常数在浸渍前后有明显的变化，浸渍后的介电常数得到了显著的提高，并且变化率较小; 浸渍后DMD膜的介电强度高于未浸渍DMD膜的介电强度。当浸渍料介电常数愈大，聚酯材料上承受的电场强度愈大，浸渍料上承受的电场强度愈小，由于聚酯材料的耐压强度很高，所以整个传输线的介电强度得到提高。

This paper presents a flexible electrical insulating composite film-DMD. Through an analysis of the film structure, a series equivalent circuit model is designed. By using this model, dielectric constant and strength are solved in not oil impregnated and oil impregnated DMD film and formulae are given. The formulae show that the dielectric constants increase obviously after impregnation and the dielectric strength of impregnated DMD film is higher than that of the not oil impregnated DMD film. The electric field strength on polyester material increases and that on impregnated material decreases with the increase of the oil dielectric constant. Due to the high dielectric strength of polyester material, the dielectric strength of the transmission line is increased.