A Composite Exponential Model to Characterize Nonlinearity Causing Passive Intermodulation Interference
Passive intermodulation (PIM) interference that occurs in communication systems could limit the communication capacity and increase the manufacturing and maintenance costs. In this letter, a composite exponential model is developed to characterize the weak nonlinearity of passive components that causes PIM generation accurately. This proposed model fully considers the correlation between the PIM products on each order and the relation of PIM products with variation of carrier powers. For verification, a microwave filter is given to demonstrate the effectiveness of this composite model, and the reliability of this model is proved by the sensitivity analysis due to measurement uncertainty. Besides, the good agreement between the calculated powers of PIM products and the measured data shows that it can provide a theoretical guidance for PIM performance assessment in engineering application, thereby evaluating the influence of PIM interference on communication quality effectively.