# Teaching

# Teaching at the Group of computational electromagnetics

Jan 14, 2015

The aim of our teaching lies in the preparation of the students for an employment in scientific research or practical work.

During the studies students should get to know the basic problems and methods concerning Electromagnetics. Furthermore this should lead to successful solutions of daily problems in Electromagnetics.

In background of a successful solution a critical analysis with theoretical concepts is a must-be.

Presentations of professionals contribute to the scientific-oriented lectures, exercises and seminars.

###### Materials of the Lectures:

Materials are found at Downloads.

# Bachelor

Lectures for bachelor students

### Electromagnetic Compatibility

#### Lecturer

Prof. L. Klinkenbusch

#### Target Group

"Hauptdiplom" Engineering Students

#### Description

Each electrical device on the market of the European Community (and
in most other countries) has to be "electromagnetically compatible",
i.e., it must not disturb other devices or the environment in an
inadmissible way. Moreover, such a device has to work without any
trouble within an electromagnetically "contaminated" environment as
well. The questions concerned with these problems are addressed by a
scientific discipline, which is shortly known as "Electromagnetic
Compatibility" (EMC). Although EMC problems are as old as the technical
utilization of electrical phenomena, EMC has reached a significant
importance within the last decades. This is mainly a consequence of the
rapid development and increasing application of electronic equipment and
devices in wireless communications, which can serve as a source as
well as a sensitive target of disturbing emissions. Moreover in the last
years there is a public and scientific discussion about a possibly
existing influence of electrical devices on the environment (e.g. high
voltage lines, mobile phones). It is clear that EMC is an
interdisciplinary challenge, where different experts are involved
(engineers, lawyers, physicians, biologists, politicians,...). Engineers
who are familiar to EMC should be able to recognize and avoid EMC
problems even in the planning stage, and to apply suitable methods while
solving such problems.

#### Contents

#### **Introduction:**

Concepts and definitions, modelling, coupling mechanisms, classification of EMC problems

#### **Shielding and Filters:**

Shielding of electro- and
magnetostatic fields, of low-frequency magnetic fields, and of
electromagnetic waves, influence of apertures, frequency-selective
filters, potential-separation and voltage limiters, cable shielding

Example: Slit-Ring Resonator

#### **EMC Measurement Techniques: **

Measuring of emitted voltages and
currents, Measuring of emitted electromagnetic fields, EMC antennas,
susceptibility tests for wire-bonded and for radiated interferences,

#### **EMC of a System: **

Stages of EMC considerations, modelling, systematical planning for complex systems

**Electromagnetic Compatibility of the Environment:**

Typical problems and examples, on public discussions on EMC.

#### Manuscript

A printed manuscript including a list of references will be distributed during the course.

#### Note

For the numerical exercises computers will be provided.

### Electromagnetic Fields I

**Lecturers**

Prof. L. Klinkenbusch and Staff

**Target group**

B.Sc. Students in Electrical Engineering

**Contents**

**Basics of Field Theory:**

Mathematical Foundations (Vector Calculus, Integral Theorems), Maxwell's Equations, Boundary Conditions

**Electrostatics:**

Definition, Field Equations, Scalar Potential, Poisson- and Laplace
Equation,, Coulomb Integral, Image Method, Uniqueness Theorem,
Capacity, Potential- and Capacity Coefficients, Dipole, Point Dipole,
Polarization, Electrical Double-Layer, Energy and Forces in
Electrostatics.

**Stationary Fields: **

Definition, Field Equations, Electric Fields of Stationary Currents
(Fields in Conductors, Ohm's Law, Kirchhoff's Equations, Duality
between Conductance and Capacity), Magnetic Fields of Stationary
Currents (Ampere's Law, Vector Potential, Biot-Savart's Law, Magnetic
Dipole, Magnetization).

**Literature**

... will be given during the course.

### Electromagnetic Fields II

**Lecturers**

Prof. L. Klinkenbusch and Staff Members

**Target group**

B.Sc. Students in Electrical Engineering

**Contents**

**Slowly-varying electric and magnetic fields:**

Electric compensation processes, induction, magnetic field energy, induction coefficients, forces in magnetic fields

**Electromagnetic fields and waves: **

Maxwell's equations, plane waves, phase velocity, polarization,
dispersion, group velocity, Poynting vector, wave guides (TEM, TE, TM),
dielectric wave guide, electrodynamic potentials, Lorenz gauge,
Hertzian and Fitzgerald dipoles, reciprocity theorem

**Quasi-stationary fields:**

Definitions, gauging, displacement-current-free quasi-stationary fields, eddy-current-free quasi stationary fields

**Literature**

... will be given during the course.

# Master

Lectures for master students

### Tomographical Methods in Medicine

#### Lecturer

Prof. L. Klinkenbusch

#### Target Group

Undergraduates and Graduates in Engineering Sciences and others

#### Contents

**Introduction:**

- Overview and Classification of Imaging Processes
- History of Imaging Processes

**Impedance-Tomography**

- Principle of Impedance-Tomography
- Fundamental Equations
- Electrodes, Current Source, Measure Amplifier
- Image Reconstruction

**Computertomography (CT)**

- Principle of CT
- Fundamentals of Signal Processing (more dimensional Fourier Transformation, Convolution, Correlation, Modulation-Transfer-Function (MTF), Sampling Theorem, Noise)
- Digital Image Processing

- Radon-Transformation
- X-ray Detectors
- CT-Reconstruction Method
- CT-Artefacts

**Magnetic Resonance Tomography (MRT)**

- Principle of MRT
- Physical Fundamental Principles (magnetic Spin Top, Precession, Nuclear Spin (MRI), Spin-Lattice and Spin-Spin-Relaxation, Bloch's Equations, Spin-Echoes)
- Tomographic Methods (Selective Excitation, Frequency- and Phase Encoding, Scanning Method)
- Structure of a MR Scanner
- Functional MRT (fMRT)

#### Literature

... will be given during the lecture.

#### Note

For the treatment of the numerical exercises Laptops will be provided.

### Fields and Waves in Biological Systems

#### Lecturer

Prof. L. Klinkenbusch

#### Target Group

Undergraduates and Graduates in Engineering Sciences and others

#### Contents

**Fundamentals** (Maxwell's equations, Diffusion, Nernst-Planck equation)

**Cell models **
(Diffusion and ionic currents in the membrane, ionic membrane-channels,
natrium-potassium pump, Nernst potentials, equivalent electric
circuits, Hodgkin-Huxley model for excitable cell membranes)

**Neuronal cells **(Function, cable equation, wave propagation along axons)

**Electromagnetics and Heart** (Function and anatomy, electrical system of the heart, electrocardiography, magnetocardiography, pacemaker)

**Electromagnetics and Brain** (Function and anatomy, electroencephalography, magnetoencephalography, deep brain stimulation)

**Electromagnetic waves in biological systems ** (Light perception, microwave effects in biological tissue, hyperthermia therapy, magnetic resonance tomography)

#### Literature

... will be given during the lecture.

#### Note

For the treatment of the numerical exercises Laptops will be provided.

### Computational Electromagnetics

#### Lecturer

Prof. L. Klinkenbusch

#### Target Group

Undergraduates and Graduates in Engineering Sciences and others

#### Description

Most practical problems in electromagnetics, e.g. the radiation
caused by a mobile phone near a human head or shielding of an electronic
circuit by a slotted metallic box, cannot be solved purely by means of
analytical methods. In many of such cases, numerical methods in
electromagnetics can be applied in an efficient way to come to a
satisfactory solution.

The course deals with two of the most successful numerical methods in electromagnetics: The first one is the *Finite-Difference Time-Domain*
(FDTD) method, which represents a finite difference formulation
perfectly adapted to the time domain Maxwell's equations. A functioning
FORTRAN source code will be explained and delivered to the students.

As a second topic the *Finite-Element Method*
(FEM) is treated, which is an excellent tool for solving full wave
frequency-domain problems especially since the introduction of the *vector edge elements.*

#### Contents

#### **Maxwell's equations:**

Integral Form, Differential Form, Properties of Matter: Non-Linear, Inhomogenenous, Anisotropic, Dispersive

#### **Finite-Difference Method:**

1-Dimensional Example: Wave
Equation, The Finite-Difference Time-Domain Method (FDTD): Stability,
Numerical Dispersion, Simulation of Scattering Problems, PML: Perfectly
Matched Layer, Efficent Modelling of Special Structures (Sub-celling,
Sub-gridding), Numerical treatment of dispersive media, Discussion of a
3-D FDTD FORTRAN Source Code

Example: Demonstration of the FDTD-method

#### **Finite-Element Method:**

1-Dimensional Example: Poisson
Equation (Definition of Finite Elements, Galerkin Method, Introduction
into Variational Methods, Suitable Functionals, Ritz Method),
2-Dimensional Problems (Discretization, Triangular Scalar and Vector
Edge Elements, Suitable Functionals, Typical Problems), 3-Dimensional
Problems (Discretization, Tetrahedral Scalar and Vector Edge Elements,
Suitable Functionals, Typical Problems)

#### **Near-To-Far-Field-Transformation (NFT):**

Free-space Green's Dyadic Function, Efficient NFT in the Frequency Domain and in the Time Domain

**Iterative solution of a system of linear equations: **

Splitting methods, Conjugate-gradient methods

#### Manuscript

A printed manuscript including a list of references will be distributed during the course.

#### Note

For the solution of numerical exercises Laptops will be provided.

### Mathematical Methods in Field Theory

#### Lecturer

Prof. Dr.-Ing. L. Klinkenbusch

#### Target Group

Undergraduates and Graduates in Engineering Sciences and others

#### Description

The course deals with those mathematical techniques, which are
helpful and essential for understanding and solving scalar (e.g.
acoustical) and vector (e.g. electromagnetic) field problems. The
methods may be important also for the numerical treatment of field
problems, which are mosty given by means of differential and/or integral
equations. Because of its strong relationship to concepts in system
theory, the course may be interesting also for students with other main
topics, e.g. communications engineering.

#### Contents

**Mathematical Fundamentals:**

Dirac's "δ-Function", δ-convergent
sequences, orthonormalized function systems, Sturm-Liouville theory (of
ordinary second-order differential equations)

#### **Green's Functions:**

Definition, properties, representations,
solution of boundary-value problems, Boundary Value Problem of the 1st
and of the 2nd kind.

#### **Helmholtz equation and Laplace equation:**

Separation in plane-polar coordinates, separation in spherical coordinates, Green's function of the free space.

#### **Multipole analysis of electromagnetic fields:**

Maxwell's
equations, Helmholtz equation, spherical- multipole analysis, multipole
expansion of a plane electromagnetic wave, diffraction by a sphere
(Theory of *Gustav Mie*)

#### Manuscript/ Literature

will be provided during the course.