In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance indicators.When the other radio frequency(RF)performance of the components is well designed,passive inter...In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance indicators.When the other radio frequency(RF)performance of the components is well designed,passive intermodulation(PIM)interference may become an important factor limiting the system’s SNR.Whether it is a base station,an indoor distributed antenna system,or a satellite system,there are stringent PIM level requirements to minimize interference and enhance network capacity in multicarrier networks.Especially for systems of high power and wide bandwidth such as 5G wireless communication,PIM interference is even more serious.Due to the complexity and uncertainty of PIM,measurement is the most important means to study and evaluate the PIM performance of wireless communication systems.In this review,the current main PIM measurement methods recommended by International Electrotechnical Commission(IEC)and other standard organizations are introduced,and several key challenges in PIM measurement and their solutions(including the design of PIM tester,the location of the PIM sources,the design of compact PIM anechoic chambers,and the evaluation methods of PIM anechoic chambers)are highlighted.These challenges are of great significance to solve PIM problems that may arise during device characterization and verification in real wireless communication systems.展开更多
In order to analyze the deleterious effects of Passive InterModulation (PIM) on high power communication satellite systems, the basic concept of PIM is introduced, and an equation for the power spectral density of the...In order to analyze the deleterious effects of Passive InterModulation (PIM) on high power communication satellite systems, the basic concept of PIM is introduced, and an equation for the power spectral density of the n-th order PIM distortion insuch systems is derived by applying flat signal-power spectrum assumption and Fourier transform method. It is indicated that PIM level generally decreases with order and the lowest frequency receive channel in the receive band is the channel of most affected by PIM interference.展开更多
Coaxial connectors are generally regarded as a kind of potential passive non-linear source when magnetic materials are applied in the coating or under-plating, which may result in serious passive intermodulation(PIM) ...Coaxial connectors are generally regarded as a kind of potential passive non-linear source when magnetic materials are applied in the coating or under-plating, which may result in serious passive intermodulation(PIM) interference and degrade the communication quality. In this paper, the effect of connector coating materials on the PIM is theoretically studied using finite element analysis(FEA) and circuit simulations. Considering the material composition both in central and outer conductor, an FEA model of connector is proposed to identify the current density in magnetic material region. An equivalent circuit model expressing the nonlinearity in coating material is developed, coupled with the non-linear transfer model. The PIM product power of the connector with related material configuration is predicted by harmonic balance simulation. Intentionally design connector samples are used in PIM tests and the measurement results are consistent with the theoretical predictions. The PIM performance in coaxial connectors is demonstrated from the perspectives of both modeling analysis and experimental investigations.展开更多
文摘In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance indicators.When the other radio frequency(RF)performance of the components is well designed,passive intermodulation(PIM)interference may become an important factor limiting the system’s SNR.Whether it is a base station,an indoor distributed antenna system,or a satellite system,there are stringent PIM level requirements to minimize interference and enhance network capacity in multicarrier networks.Especially for systems of high power and wide bandwidth such as 5G wireless communication,PIM interference is even more serious.Due to the complexity and uncertainty of PIM,measurement is the most important means to study and evaluate the PIM performance of wireless communication systems.In this review,the current main PIM measurement methods recommended by International Electrotechnical Commission(IEC)and other standard organizations are introduced,and several key challenges in PIM measurement and their solutions(including the design of PIM tester,the location of the PIM sources,the design of compact PIM anechoic chambers,and the evaluation methods of PIM anechoic chambers)are highlighted.These challenges are of great significance to solve PIM problems that may arise during device characterization and verification in real wireless communication systems.
文摘In order to analyze the deleterious effects of Passive InterModulation (PIM) on high power communication satellite systems, the basic concept of PIM is introduced, and an equation for the power spectral density of the n-th order PIM distortion insuch systems is derived by applying flat signal-power spectrum assumption and Fourier transform method. It is indicated that PIM level generally decreases with order and the lowest frequency receive channel in the receive band is the channel of most affected by PIM interference.
基金supported by the National Natural Science Foundation of China (62090012,62031016, 61831017)the Sichuan Provincial Science and Technology Important Projects (2019YFG0498, 2020YFG0282, 2020YFG0452 and 2020YFG0028)。
文摘Coaxial connectors are generally regarded as a kind of potential passive non-linear source when magnetic materials are applied in the coating or under-plating, which may result in serious passive intermodulation(PIM) interference and degrade the communication quality. In this paper, the effect of connector coating materials on the PIM is theoretically studied using finite element analysis(FEA) and circuit simulations. Considering the material composition both in central and outer conductor, an FEA model of connector is proposed to identify the current density in magnetic material region. An equivalent circuit model expressing the nonlinearity in coating material is developed, coupled with the non-linear transfer model. The PIM product power of the connector with related material configuration is predicted by harmonic balance simulation. Intentionally design connector samples are used in PIM tests and the measurement results are consistent with the theoretical predictions. The PIM performance in coaxial connectors is demonstrated from the perspectives of both modeling analysis and experimental investigations.
