Abstract—Passive Intermodulation (PIM) distortion which results from passive components such as antennas, connecters, etc. poses significant challenges in wireless communications by limiting cell coverage and data rates. In Carrier Aggregated (CA) Long-Term Evolution (LTE) system, PIM is manifested as self-interreference when intermodulation products of the transmitted signal leak to the receiver. The primary goal of this paper is to develop a new behavioral model for passive nonlinearities enabling PIM distortion in LTE systems to be predicted. The analysis employs a Threshold-Decomposition-based Piecewise Linear (TD-PWL) model to represent a passive nonlinearity and predict PIM in CA-LTE system. Simulation results show that the proposed model accurately predicts PIM and highlight its superior numerical stability and accuracy over polynomialbased models. These results position the PWL model as a promising choice in the design of PIM cancellation schemes.