PIM – Low Passive Intermodulation PCBs
Passive Intermodulation (PIM) phenomenon manifests itself in generation of combinatorial frequency signals, resulting from nonlinear mixing of two or more RF signals. PIM effect has been the subject of increasing concern in the wireless community because it causes spurious electromagnetic emission and remains a major limiting factor of digital communication systems' performance.
The significance of the PIM related problems dramatically increases nowadays in the context of the trend towards integrated systems where the base station antennas and the system RF front end comprise sophisticated radiating elements, combined with complex antenna beamforming networks, power distribution and matching circuits fabricated on a single PCB. Therefore reduction of the PIM product generation in PCB has recently become the paramount for further advancement of digital systems.
Trackwise is proud to have been a partner in a IEEE award-winning research programme "Mechanisms of Passive Intermodulation and means for mitigation on printed and layered transmission lines" led by Queen’s University Belfast and funded by EPSRC. Research was carried out at the Institute of Electronics, Communications and Information Technology (ECIT) www.ecit.qub.ac.uk.
One of the many conclusions of this study is that properly manufactured PCBs on properly constructed laminates have no difficulty in meeting stringent PIM performance (typical requirement is for 3rd order IM products to be below 153dBc) but that the quality of the laminate and PCB manufacturing technique is of crucial importance in achieving this low PIM performance.
If you have a requirement for Low Passive Intermodulation (PIM) PCBs, please contact Trackwise.
The following is just one of the many papers resulting from this research program. If you would like copies of these papers, please contact Trackwise.
Effect of Trace Dimensions - PIM