PhD Defence Ridvan Aba | Zoning and Monitoring Methods for EMI Risk Mitigation in Reverberant Environments

Zoning and Monitoring Methods for EMI Risk Mitigation in Reverberant Environments

Ridvan Aba is a PhD student in the department Radio Systems. (Co)Promotors are prof.r.ir. F.B.J. Leferink & dr. R. Vogt-Ardatjew from the faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS), University of Twente.

Modern medical systems increasingly rely on electronics, wireless communication, sensors, and connected equipment, creating complex electromagnetic environments (EMEs). In enclosed medical spaces, electromagnetic interference (EMI) risk depends not only on the source, but also on multipath propagation, spatial field variability, and installation conditions. Generic separation rules and free-space models may therefore be inadequate for realistic risk assessment.

This thesis develops an environment-aware approach to EMI-risk mitigation through two contributions: an indoor zoning methodology for enclosed medical spaces, especially ultra-high-field magnetic resonance imaging (MRI) rooms, and a passive shielding integrity monitoring method using signals-of-opportunity (SoOp) and software-defined radio (SDR) receivers.

The thesis first links onsite EME characterization to reverberation chamber (RC) theory and applies statistical field interpretation to enclosed environments. The proposed zoning methodology includes both line-of-sight and scattered field components when determining minimum separation distances. Validation in a vibrating intrinsic reverberation chamber (VIRC) and an MRI room shows that it provides more realistic zoning guidance than methods based solely on free-space propagation.

The second contribution enables shielding integrity to be monitored over time. Multiple low-cost SDR receivers use ambient SoOp to detect changes in shielding performance without introducing an intentional EMI source. Intended transmitters can increase the achievable dynamic range when required.

Overall, the thesis advances electromagnetic compatibility (EMC) practice from generic assessment toward environment-aware zoning and operational monitoring. The proposed methods can support medical equipment development, installation guidance, clinical procedures, and the protection of other critical environments, including nuclear facilities and TEMPEST applications.