Localization Of Passive Intermodulation Based On The Concept Of K-Space Multicarrier Signal

Passive intermodulation (PIM) effect is specific nonlinearity which occurs in high microwave devices due to the multi-physics field coupling. Recently, with the rapid development of commercial high capacity communication system (HCCS) [11], PIM which occurs in high-power microwave devices, such as multiplexer, filter, antenna in wireless base stations, have been becoming more and more common. As a result, PIM localization based on the PIM physical mechanism becomes an urgent task and precondition to suppress and eliminate PIM efficiently.In this paper, we indicate that if a reference PIM source can be introduced into the standard PIM testing system, and the amplitude and frequency dependent phase difference between the reference and the real PIM products can be considered to construct a k-space multicarrier signal. As a result, PIM localization algorithms for both wideband and narrowband devices can be proposed based on the inverse k-space Fourier transform and inverse optimization of the partial multicarrier signal.Based on theoretical analysis of coherent measurement, the PIM localization system prototype has been retrieved including the coherent signal sources, duplexer, filter, AD, amplitude/phase detector and system control software kit, etc. Lacking an available high-power PIM test system, we used diodes mounted on a transmission line to simulate PIM sources. The diodes were chosen as Agilent HSMS2820. The PIM generation mechanism based on MIM model and diode nonlinearity has been compared and proved to be feasible to use the second harmonic component was selected to simulate the "PIM" product.Simulation and experimental results validate the effectiveness of the proposed approaches. Our methods can solve the difficulty of multipoint PIM localization, and can be widely used in the design, production, testing and troubleshooting of high power microwave systems.