ece357 introduction
DESCRIPTION
To a course in U of TTRANSCRIPT
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
• 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 [email protected] Office hours: – Thursdays 3-4pm – 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 Blackboard
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)
ECE357 / Prof. S. V. Hum
Laboratories
• 3 laboratories, bi-weekly – Starting in February
• 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 (Box
35, 4th floor Bahen building)
ECE357 / Prof. S. V. Hum
Midterms
• 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
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
24 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
A Question to Ponder
• 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