Welcome! ECE357H1S: Electromagnetic Fields

ECE357 / Prof. S. V. Hum

Welcome!

ECE357H1S: Electromagnetic Fields

Lecture Section L01 Prof. Sean Victor Hum

ECE357 / Prof. S. V. Hum

Welcome

•  Course website via Blackboard http://portal.utoronto.ca http://www.waves.utoronto.ca/prof/svhum/ece357.html

•  Important information distributed through Blackboard –  Notes, problem sets, announcements, …

•  Please login and familiarize yourself with the site

ECE357 / Prof. S. V. Hum

Contact Information Prof. Sean Victor Hum BA5122 sean.hum@utoronto.ca Office hours: –  Tuesdays 4-5pm –  Anytime by appointment

ECE357 / Prof. S. V. Hum

Textbook / References •  Required

–  D. Cheng, Field and Wave Electromagnetics, 2nd ed., Addison-Wesley, 1989

•  Recommended 1.  K. R. Demarest, Engineering Electromagnetics,

Prentice-Hall, 1997 2.  Simon Ramo, John R. Whinnery, and Theodore Van

Duzer, Fields and Waves in Communication Electronics, 3rd Ed.

3.  E.M Purcell, Electricity and Magnetism, Vol. II, 2nd Ed., (Berkeley Physics Series)

Course Grading Term Test 1 15%

Term Test 2 15%

Quizzes (approx. bi-weekly, 5 total)

10%

Laboratory Work (bi-weekly, 3 experiments)

15%

Final exam 35%

ECE357 / Prof. S. V. Hum

Lectures

•  Material follows course notes but expect variations in depth (i.e. keep good notes!)

•  I will run frequent surveys after lectures to determine which concepts are causing the most difficulty (‘muddiest concepts’) – Please participate! – This will help me tailor lecture and online

materials to help you the most

ECE357 / Prof. S. V. Hum

ECE357 / Prof. S. V. Hum

Tutorials / Assignments

•  Weekly tutorials (1 hour tutorial format) •  Tutorials will cover previous and present

week of material •  Weekly problem sets, not marked

–  Issued Mondays – Solutions covered in tutorials, online

•  Quizzes held at conclusion of tutorial (last 10 minutes) – 5 total, bi-weekly, see schedule

ECE357 / Prof. S. V. Hum

Laboratories

•  3 laboratories, bi-weekly –  Starting week of February 1 – see schedule

•  Experiment 1: Design of a double-stub matching network

•  Experiment 2: Waves on transmission lines •  Experiment 3: Standing waves and waveguides •  Laboratory reports

–  Completed individually and independently –  Due two weeks later at 16:00 in collection boxes (4th

floor Bahen building)

ECE357 / Prof. S. V. Hum

Term Tests (2)

•  Scheduled outside lecture time, TBD •  Cover to the beginning of the course, but

with emphasis on un-tested material. •  One double-sided 8.5x11” aid sheet

allowed (same for final exam)

ECE357 / Prof. S. V. Hum

Why Study Fields and Waves?

•  All of our electronics, radio/microwave, photonic/optical, and X-ray devices rely on properties of electric and magnetic fields

•  EM theory applies to all electromagnetic fields, regardless of frequency

ECE357 / Prof. S. V. Hum

The Electromagnetic Spectrum

LG

12

13

USS Shiloh - Radar console in the Combat Information Center

14 ESO/José Francisco Salgado (josefrancisco.org)

Cosmic microwave background radiation

15

Real-time MRI of a human heart

Tomáš Vendiš, Wikimedia / Wikipedia

MDA / ESA

MDA / ESA

Photonics Sweden

ECE357 / Prof. S. V. Hum

Circuit Theory vs. EM Field Theory

•  When the size of a structure is much smaller than a wavelength, there is negligible variation in the electric/magnetic fields (voltages/currents) across the structure –  Can apply circuit theory

(KCL, KVL, …)

ECE357 / Prof. S. V. Hum

Circuit Theory vs. EM Field Theory

•  As the structure gets large / wavelength gets small, such that this is no longer true, circuit theory is no longer applicable –  Need EM theory to analyze the system

ECE357 / Prof. S. V. Hum

EM Field Quantities

ECE357 / Prof. S. V. Hum

Maxwell’s Equations •  EM theory is completely characterized by 4

major vector equations:

•  Before delving to deeply into these, we will start with transmission lines which are closer to circuits

Constitutive relations (simple media):

ECE357 / Prof. S. V. Hum

What you will learn in ECE320

•  Transmission line theory •  Fundamental electromagnetics theory •  Unguided waves in space: plane waves •  Guided waves and waveguides

ECE357 / Prof. S. V. Hum

Transmission Line Theory •  Transmission lines are

used in countless ways in modern society –  Communications –  Electronic circuits /

computers –  Power distribution –  Photonics –  …

•  TL theory becoming increasingly relevant in modern circuit design as clock frequencies continue to climb –  “Signal integrity

engineering”

ECE357 / Prof. S. V. Hum

Transmission Line Theory

•  You will learn: –  Voltage and current

waves on a transmission line

–  Transient and harmonic behaviour of transmission lines

–  Use of the Smith Chart –  How to design

transmission line matching circuits

ECE357 / Prof. S. V. Hum

Fundamental EM Theory

•  You will learn: –  Maxwell’s equations –  Boundary conditions –  Helmholtz equation

•  Theoretical building blocks for studying guided/unguided EM waves

ECE357 / Prof. S. V. Hum

Unguided Waves •  Examples:

–  Radio waves broadcast from an antenna

–  Light radiation from a laser –  X-rays

•  Plane waves are simple approximations of waves in real life that can be used to study the propagation of electromagnetic fields in free space

ECE357 / Prof. S. V. Hum

Unguided Waves

•  You will learn: – Plane waves and propagation characteristics – Transmission and reflection at a variety of

media interfaces – Analogies with transmission lines

ECE357 / Prof. S. V. Hum

Guided Waves •  More advanced analysis

of various transmission lines and modes for guiding EM waves

•  Specific examples: –  Rectangular waveguide –  Parallel plate waveguide –  Planar transmission line –  Dielectric-based

transmission lines (e.g. fibre optics)

Transmission Lines

ECE357 / Prof. S. V. Hum

What is a Transmission Line?

ECE357 / Prof. S. V. Hum

31 ECE357 / Prof. S. V. Hum

Examples of Transmission Lines

Transmission Line Example

ECE357 / Prof. S. V. Hum

Consider a modern PC motherboard:

•  The bus line is a two-conductor transmission line •  Let us connect a source (e.g. clock oscillator) to the line and terminate the line in a resistive load •  We will now vary the frequency of the source to change the wavelength λ

Transmission Line Voltage Observations

ECE357 / Prof. S. V. Hum

Let’s observe the voltage at many points along the line (relative to the ground plane) and observe the behaviour as a function of time

z

Question

•  What kind of equivalent circuit allows the effect of the source to be delayed the way we have seen in the demonstration?

ECE357 / Prof. S. V. Hum