随着载波功率不断提高及通信设备精巧化的发展趋势，无源器件固有的非线性会引起严重的无源互调(PIM)干扰，由此产生的影响不可忽略。针对此现象，以微波矩形波导为研究对象，考虑PIM的主要产生机理: 量子隧穿效应和热电子发射效应，在波导法兰金属—金属(MM)接触模型的基础上，提出一种计算PIM功率的方法。将两种非线性效应用隧穿电阻Rnlc的I-V特性来表示，运用谐波平衡仿真和Matlab软件进行交流仿真，分析并计算流经隧穿电阻的非线性电流、其两端的压降以及波导连接中的PIM功率。结果表明，采用此方法计算得到的PIM功率随接触压力的增大先是明显下降，当压力达到一定值后，下降变缓慢且逐渐趋于平衡状态。

With the increase of carrier power, the development trend of sophisticated communication equipment, the inherent non-linearity of passive components will cause serious Passive Inter-Mmodulation (PIM) interference, where the resulting impact can not be ignored. In view of this phenomenon, the microwave rectangular waveguide is taken as the research object, considering the main mechanism of PIM: quantum tunneling effect and hot electron emission effect. Based on the contact model of the waveguide flange Metal-Metal (MM), a method of calculating the PIM power is proposed. The two non-linear effects are represented by the I-V characteristics of the tunneling resistor Rnlc, using harmonic balance simulation and Matlab software for AC simulation. The non-linear current flowing through the tunneling resistor and the voltage drop at both ends and the PIM power in the waveguide connection are analyzed and calculated. The results show that the calculated PIM power varies with the contact pressure. The value of PIM power drops significantly at first with the increase of pressure. Then the value of PIM power declines slowly when further increasing the pressure and reaches a balanced state finally.