Abstract:In modern wireless communication, passive intermodulation is an important factor affecting the transmission quality of communication signals. Dual-tone intermodulation testing can effectively measure the nonlinear characteristics of passive devices, but it is hard to accurately predict the nonlinear distortion of devices excited by broadband signals. A method for analyzing the Passive Intermodulation characteristics of RF connectors with broadband signal excitation is proposed. Through the dual-tone intermodulation test, the passive nonlinear transmission mathematical models of RF connectors are derived. An equivalent broadband signal considering normal distribution is provided as the excitation source to the connectors. Mathematical calculation results of the proposed model show that the broadband Passive Intermodulation power distribution is the same as the broadband signal power distribution. The bandwidth of the nth-order broadband Passive Intermodulation is n times that of the original broadband signal. It is observed that the power of Passive Intermodulation products with broadband signal excitation are higher than that of the dual-tone signal. Thus, the signal to noise ratio decreases, indicating that the PIM interference induced by the broadband signal in the transmission process is more serious compared with that induced by two Continue Wave(CW) signals. Simulations are conducted by importing the proposed broadband signal and nonlinear transfer function to an equivalent circuit. The simulation results show good consistency to the theoretical calculation, which proves the effectiveness of this analysis method.