ELECTROMAGNETICS AND APPLICATIONS

Handouts:

• Info sheet (DRAFT),

• Syllabus (outline and schedule DRAFT)

• Lecture #1 slides (only this time)

Luca Daniel

L1-2

Course Outline and Motivations

• Electromagnetics:– How to transport signals and power on “guided systems”

• Applications– digital electronics: e.g. analyze transients when you send a

signal from the CPU chip to the GPU chip, or from your keyboard to your iPad

CPU

RAM

GPU A/DD/A

keyboard

iPad

L1-3

Course Outline and Motivations

• Electromagnetics:– How to transport signals and power on “guided systems”

• Applications– digital electronics: e.g. analyze transients when you send a

signal from the CPU chip to the GPU chip, or from your keyboard to your iPad

– analog and biomedical electronics: e.g. match load of RF cables bringing signal from power amplifier to MRI coil antennas to avoid reflections

CPU

RAM

GPU A/DD/A PA

L1-4

Course Outline and Motivations

• Electromagnetics:– How to transport signals and power on “guided systems”

• Applications– transport of light: e.g. fiber optics (around your globe and in

your neighborhood cable company),

– or on-chip silicon-photonics

Fiber Communications Around the Globe Prof. Watts, MIT

L1-5

Course Outline and Motivations

• Electromagnetics:– How to transport signals and power on “guided systems”

• Applications– transport of electricity in power-lines

– fluids in oil pipes, or blood in arteries and micro-fluidic channels

Prof. Han, MIT

L1-6

Course Outline and Motivations

• Electromagnetics:– How to analyze, design and couple energy to/from resonators

• Applications– e.g. in cellphone receivers: electrical (LC) resonator filters

– and MEMs resonators filters

LNA

ADC

ADC

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Q

LO

Micron Technology, Inc

L1-7

Course Outline and Motivations

• Electromagnetics:– How to analyze, design and couple energy to/from resonators

• Applications– optical resonators (e.g. lasers)

Prof. Ippen, MIT

L1-8

Course Outline and Motivations

• Electromagnetics:– How to analyze, design and couple energy to/from resonators

• Applications– acoustical resonators (e.g. musical instruments and vocal

chords, and... your own shower “room”)

d

vocal chords

L1-9

Course Outline and Motivations

• Electromagnetics:– How to transport signals and power on “non-guided systems”

• Applications– wire antennas (e.g. inside your iPhone, or wireless router)

– aperture antennas (e.g. satellite, radar, parabola TV)

L1-10

Course Outline and Motivations

• Electromagnetics:– How to transport signals and power on “non-guided systems”

• Applications– acoustical antennas (e.g. rock concert loudspeaker)

L3-11

• Review of Fundamental Electromagnetic Laws

• Electromagnetic Waves in Media and Interfaceso Waves in homogeneous lossless and lossy media

o Power flow and energy balance (Poynting Theorem)

o Waves at interfaces

• Digital & Analog Communicationso TEM transmission lines (Telegrapher eqn.)

o Transients in digital communication wires

o Waves in RF cables

o TEM resonators

• Microwave Communicationso metallic waveguides

o microwave cavity resonators

Course Outline

L3-12

• Optical Communications• Wireless Communications

o short dipole radiation in near & far field

o receiving and transmitting antennas

o array of antennas

o wireless communication links

o aperture antennas, and understand diffraction

• Acoustics

Course Outline (continue…)

L1-13

• Course Overview and Motivations

• Maxwell Equations (review from 8.02)

– in integral form

– in differential form

– EM waves in homogenous lossless media

– EM Wave Equation

– Solution of the EM Wave equation Uniform Plane Waves (UPW)

Complex Notation (phasors)

– EM Waves in homogeneous lossy media

Today’s Outline

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L1-14

Faraday’s Law:

Maxwell’s Equations (in integral form)

Electric field [volts / meter] = [V / m]

Electric displacement [amperes sec / m2] = [A s / m2]

Electric charge density [coulombs / m3] = [C / m3]

Magnetic field [amperes / meter] = [A / m]

Magnetic flux density [Tesla] = [T] = [Webers / m2] = 104 [Gauss]

Electric current density [amperes/m2] = [A / m2]

ˆS V

D nda dv Gauss’sLaws

ˆ 0 S

B nda

C S S

ˆ ˆ ˆH ds D nda J ndat

Ampere’s Law:

C S

ˆ ˆE ds B ndat

B H

D E

J E

6oIn vacuum: =1.26 10 [Henries]

12oIn vacuum: 8.854 10 [Farads /m]

E

H

L1-15

If the material properties

ε, μ and σ vary with:

Field direction

Field intensity

Position

Frequency

Time

the media is called:

Anisotropic

Non-linear

Inhomogeneous

Dispersive

Non-Stationary

Types of Media

,D E , B H J E

L1-16

Maxwell’s Equations (in differential form)

S V

D nda dv

ˆ 0 S

B nda

C S

D ˆH ds (J ) ndat

C S

ˆE ds B ndat

D

BEt

B 0

DH Jt

Stokes Theorem:

ˆV

S

F nda Fdv Gauss Divergence Theorem:

ˆ ˆA

c

F ds F nda

L1-17

2Use identity: F F F

0

Second derivative in space second derivative in time,therefore solution is any function with identical dependencieson space and time (up to a constant)

Maxwell’s Equations (in homogeneous lossless media)

0

0Faraday’s Law:

BEt

Ampere’s Law:

D D E

Gauss‘sLaw

DH Jt

B 0 B H

22

2EM Wave Equation : E E 0

t

is homogeus

[ ]

E Ht

222EYields: E E

t

ConstitutiveRelations

2

2E

tEliminate H :