37125 - Electromagnetic Compatibility M

Learning outcomes

The course provides the knowledge of the main concepts in the field of electromagnetic compatibility of electric/electronic devices. The main topics are crosstalk, conducted and radiated emissions with models for the analysis. The students are given an understanding for the solution of conducted and radiated electromagnetic interference, with particular reference to EMI filters, methods and techniques of electromagnetic shielding and measurement in reverberation chamber. The basic knowledge of electromagnetic wave propagation both in an arbitrary medium and in guiding structures is also provided. The topics are presented with reference to practical applications. Lectures are integrated with numerical and laboratory demos.

Course contents

Introduction to electromagnetic compatibility

History of electromagnetic compatibility (EMC). Basic definitions. Requirements of EMC according to the EMC Directive 2014/30/EU: emission and immunity. Electromagnetic interference model. Decibel and electric length. Choice of the electromagnetic model for an EMC problem: quasistationary and non stationary electrodynamics.

Crosstalk

Capacitive (electric) coupling. Inductive (magnetic) coupling. Capacitive-inductive coupling. Circuit models for crosstalk.

Nonideal behaviour of electrical circuit components

Real lumped component models of conductors, capacitors, inductors and resistors. Resistance and inductance of conductors versus frequency. Frequency response of the impedance of real lumped components: capacitors, inductors, resistors.

Conducted emission and immunity

Common mode and differential-mode conducted emissions. Sources of conducted interference. Standards. Methods and instruments of measurement. Spectrum analyzer and EMI receiver basics. Line impedance stabilization network (LISN). Current probes. Troubleshooting conducted interference: filters, power supply, positioning of components inside the equipment. Model for the assessment of conducted emissions in SMPS power converters. EMI filters. Conducted immunity issues. Immunity testing. Disturbances in the distribution networks. Pulsed disturbances: burst, surge and test systems. Voltage variations and test systems. Electrostatic discharges. Standards.

Basic antennas

Electromagnetic field radiated by elemental dipoles. Electric and magnetic dipoles. Near- and far-field approximation. Uniform plane waves (TEM) in a lossless medium. Examples of EMC antennas: monopole, dipole, biconical, logperiodic and bilog antennas. Antenna factor and antenna bandwidth. Baluns.

Radiated emission and immunity

Models for the evaluation of radiated emissions from wires and PCB lands. Standards. Methods and instruments of measurement. Radiated emission test sites. Troubleshooting radiated emissions.
Radio frequency immunity. Radiated immunity issues. Bifilar line terminal voltages induced by a uniform plane wave. Standards. Methods and instruments of measurement. Test sites. Troubleshooting radiated immunity.

Electromagnetic shielding

Shielding effectiveness of a planar shield. Methods for the calculation of shielding effectiveness. Shielding of uniform plane waves. Approximation for a near-field source. Shields with apertures. Transfer impedance of enclosures, cables, connectors, junctions. Techniques for the measurement of the shielding effectiveness. Shielding materials.

Reverberation chambers

Generalities. Waveguides and cavities. Resonant frequencies. Application to EMC measurement. Test equipment. Mode stirring and mode tuning. Validation of the chamber. Measurement of shielding effectiveness of materials, enclosures, cables, connectors, gaskets.

EMC Directive 2014/30/EU

Scope and definitions. Conformity assessment procedures for electric and electronic equipment. EMC analysis flow chart.

Readings/Bibliography

C. R. Paul, Introduction to Electromagnetic Compatibility, Wiley, 2006

H. W. Ott, Electromagnetic Compatibility Engineering, John Wiley & Sons, 2009

P. A. Chatterton, M. A. Houlden, EMC Electromagnetic Theory to practical design, John Wiley & Sons, 1991

Teaching methods

Laboratory demos will help students to better understand the material covered in the lessons.

Seminars from industry people will also be hold.

Assessment methods

Oral exam.

Teaching tools

Handouts of slides are available to students on https://virtuale.unibo.it/.

Office hours

See the website of Leonardo Sandrolini