A paper on the little understood phenomenon of passive intermodulation (PIM) that causes signal distortion and increased noise levels, and limits the efficiency of communications systems and ultra fast digital circuits has won the prestigious IEEE 2010 Microwave Prize.

Its authors include Alexander Schuchinsky, a researcher at Queen's University Belfast's Institute of Electronics, Communications and Information Technology (ECIT).

Dr Schuchinsky - along with co-authors from North Carolina State University - won the prize for their paper, Electro-Thermal Theory of Intermodulation Distortion in Lossy Microwave Components.

The work described in the paper results directly from a recently completed three-year EPSRC funded study into the mechanisms of PIM generation in printed circuit boards (PCBs) and passive microwave components, undertaken by researchers from ECIT's High Frequency Electronics Circuits Group.

With the majority of electronic devices based on PCB technology, the project's main objective was to understand how the PIM performance of PCB laminates, circuit interconnects and integrated chips affects the signal integrity of systems with distributed wave interactions.

Research into this previously unexplored territory required highly sophisticated experimental techniques, elaborate theoretical models and advanced simulation tools. These in turn involved the developments in a range of interrelated disciplines including material science, high precision microwave measurements, specialised modelling software and novel manufacturing processes.

ECIT's work has already resulted in significant improvements in fabrication and processing techniques enabling consistent production of PCB laminates and printed boards with extremely low PIM levels. In addition, newly developed methods for mapping electromagnetic field patterns that permit the non-destructive identification and detection of PIM sources in printed circuits and microwave devices have dramatically increased the efficiency of production testing and improved manufacturing yield.

A number of industrial partners are now using the research outcomes to reduce electromagnetic pollution and background noise and improve service quality and reliability at considerably lower power consumption and significantly reduced spurious microwave emissions. They include Castle Microwave, Summitek Instruments, Taconic International and Trackwise Designs.