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PhD defence by Morten Sørensen; Predicting Radiated Emission of Apparatus Configured of Modules by Means of Numerical Methods and Module Level Measurements


27.11.2018 kl. 12.30 - 16.00


Predicting Radiated Emission of Apparatus Configured of Modules by Means of Numerical Methods and Module Level Measurements

If an apparatus, few weeks before it is released for production, fails the mandatory legal electromagnetic compliance (EMC ) test, it can cause extremely complicated, expensive, and time-consuming modifications and, in worst case, delays. Conversely, the fear of failed mandatory EMC test late in a project phase can cause overdesign and, hence, unnecessary and costly improvements. Therefore, there is a need for methods to predict EMC properties early in the project phase.

This thesis addresses different methods to estimate the radiated emission from an apparatus configured of modules early in the project phase and long time before the apparatus is finalized. The methods make use of both module measurements, simulations and a combination of these.

Radiated emission from an apparatus can be divided into radiation due to common mode currents on attached cables (common mode emission) and direct radiation from modules. This thesis investigates the validity of reducing common mode emission to lumped element models. The focus is on the ”Workbench Faraday Cage” method (IEC standard 61967-5).

Regarding direct radiated emission, the main idea is to measure the tangential electrical and magnetic fields on a ”Huygens’ box” (HB) that encloses the sources and use the measured fields as source for simulation (the HB method). The thesis analyses everyday challenges and their influence on test results are evaluated. This include cables connected to the equipment under test, packaging of modules in housings, effects of scattering from nearby objects and approaches to reduce the test time in near-field scans.

The thesis also presents a structure for calibration and characterization of near-field probes at high frequencies and finally the thesis discusses the sampling requirements for emission source microscopy.

Assessment Committee:
Head of R&D, Dr. Sc. (ETHZ), Sven Kühn, Schmid & Partner Engineering AG, Project Leader EM Sensor Technology and Member of the Extended Executive Committee at IT’IS Foundation/ETH Zurich, and Head of Product Safety and Regulation at ZMT Zurich MedTech AG
Associate Professor, D.Sc., Ville Viikari, Aalto University
Associate Professor Ole Kiel Jensen, Department of Electronic Systems (Chairman), Aalborg University

Professor Gert F. Pedersen, Aalborg University

Associate Professor Ondrej Franek, Aalborg University
Associate Professor Hans Ebert, Aalborg University

Associate Professor Flemming Bjerge Frederiksen, Aalborg University

After the defence a reception will take place at Selma Lagerlöfs Vej 312 (Novi 9). Please feel free to join


Free of Charge


Antennas, Propagation and Millimetre-wave Systems, Department of Electronic Systems


Selma Lagerlöfs Vej 312 (Novi 9), room 1.112/1.114

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