Lecture: 1
Introduction to Electromagnetics
Engineering
Dr. Yogesh Kumar Choukiker
School of Electronics Science Engineering
Department of Communication Engineering
Microwave and Antenna Division
VIT University, Vellore, India
1
COURSE OBJECTIVE
 To look into the origins of Electromagnetic Field Theory (EMFT) and major
developments over the years
 To identify major technology areas and applications where knowledge of
EMFT plays a vital role
 To prepare the mathematical foundations such as vector calculus and operators
 To study the laws governing static electric and magnetic fields
 To study the Maxwell’s equations and Time-varying nature of electric and
magnetic fields
 On successful completion of the course, the student is expected to be in a
position to study advanced courses such as ‘Antennas & Wave Propagation’ ,
‘Microwave Theory & Techniques’ & ‘Communication Engineering’ etc
OUR PLAN
 We have effectively 45 x 50 min. = 37.5 hours of theory lecture time to
complete this course
 And 3 x 50 min. = 2.5 hours per week
 We have 14 lecture classes before CAT – I and 14 lecture classes thereafter till
CAT - II and the remainder 17 lecture classes upto Term End Examination
(TTE)
 In between CAT – I, CAT – II and TTE, we will have 3 Quizz papers and
Assignments
 We will follow ‘Elements of Electromagnetics’ by Matthew N. O. Sadiku, 4/e.
Any additional reference will be specified during classes
What is Electromagnetism ??
 The fundamental forces of nature that connect Matter and Energy can
be defined by the interactions of elementary particles. Matter (Quarks,
Leptons), Force Carriers (Gluons, W&Z Bosons, Photons, Gravitrons)
Standard Model Of
Physics
Gravitational
Electromagnetic
Strong
Nuclear
Weak Nuclear
 Electromagnetics is the study of forces between elementary charged
particles and their manifestation (fields, energy)
Fundamental Fource
PARTICLE
/QUANTUM
Strong nuclear gluon
Electromagnetic photon
W+,W- & Z
Weak nuclear
bosons
gravitron
Gravitation
(tentative)
FORCE
4
RELATIVE
STRENGTH
1
7 X 10-3
MASS
(GeV)
0.14 (?)
none
RANGE
(meters)
10-15
infinite
10-5
80-90
10-17
6 X 10-39
none
infinite
 The nucleus of an atom is bound by ‘Strong Nuclear’ force, which
binds protons and neutrons together. Here the electromagnetic
repulsion of ‘like-charged’ protons is smaller compared to ‘Strong
Nuclear’ force.
 The ‘Weak Nuclear’ force results in transformation of protons to
neutrons and vice versa, radioactive decay etc
 Gravitational force binds the galaxies, star systems etc
Identification of Forces
 Hydro-electric power ?
Gravitational Force
 Friction between objects ?
Electromagnetic Force
 Nuclear Fusion/Fission ?
Strong Nuclear Force
 Chemical Explosion ?
Electromagnetic Force
 Solar Energy ?
Strong Nuclear Force
 Pressure & Strain ?
Electromagnetic Force
 -ray decay ?
Weak Nuclear Force
 Tidal Energy ?
Gravitational Force
 If you are curious to know more about the nature of forces refer to
‘Fundamental Forces of Nature : The Story of Gauge Fields’ by Kerson
Huang
Where Else Can I Find Electromagnetism ?
 Mobile Phones and many consumer electronic gadgets. Almost any
device you plug into electrical mains works on electromagnetic
principles
Other Application Areas
 Plane wave hitting a ship. We study plane wave propagation in this
course. This forms basis for studying Radar, Antennas etc
Field Distribution
Field Distribution
Field Distribution
Field Distribution
 Plane wave hitting various objects. We study plane wave
propagation in this course. This forms basis for studying
Radar, Antennas etc
5
Field Distribution
Field Distribution
 Biological effects of Mobile Phones analysed using a Human
Model.
Field Distribution
Field Distribution
 At system level, Electromagnetic Interference (EMI) among highly dense
electronic packages is a very crucial problem
 Electromagnetic Compatibility (EMC) forms a major area of interest in
Chip Industry, Power Transmission, Wireless Networks etc.
Biological Effect of EM Radiation
 Biological effects of Mobile Phones analysed using a Human Model.
EMI and EMC
 At system level, Electromagnetic Interference (EMI) among highly
dense electronic packages is a very crucial problem
 Electromagnetic Compatibility (EMC) forms a major area of interest in
Chip Industry, Power Transmission, Wireless Networks etc.
Electrical Discharge
 Studying lightning strike and its effects on electrical systems and
navigational aids carried on an aircraft
Antenna & Radiation of EM Waves
 Radiation from a dielectric lens antenna for industrial radar
Waveguides
 EM wave propagation through waveguide bends
Electromagnetic Spectrum
Some Fundamentals
 Force is an external stimulus on an object, that brings about motion of a body
in rest or vice versa, change direction of motion or cause physical contraction
or expansion.
Force is measured in Newtons 1 N = 1 Kg m/s2
(remember Newton’s Laws of Motion ?)
 Energy is the capacity of a physical system or phenomena to carry out work.
It can be in any form, electrical, mechanical, thermal, chemical, nuclear, light,
acoustic etc
Energy is measured in Joules 1 J = 1 N-m
 Power is rate of doing work or energy consumed per unit amount of time.
Power is measured in Watts 1 W = 1 J/s
 Work is energy expended by a force to displace an object by unit distance.
Work has same units as energy
How can we relate them ??
 Work is force applied on an object to displace it by a distance.
Work = Force x Distance
 Work is also change of energy from one form into another
Work =  Energy
By which we can say that  Energy = Force x Distance
 Power is rate of doing work or rate at which energy is absorbed or
expended.
Power =  Energy /  time
Similarly can you relate terms such as Momentum, Angular Momentum,
Torque etc ?
We will study the electrical equivalents of the mechanical concepts later
Timeline and Pioneers
 6th Century BC
Thales of Miletus Rubbing fur on
amber would cause an attraction between the two, Origin of
static electricity
 1st Century BC
of some stones
Shephard MagnesMagnetic properties
 1600 AD
William Gilbert
bodies and earth as a big magnet
Magnetic
 1663 AD
Otto von Guericke
electrostatic generating machine
First
 1745 AD
Pieter van Musschenbroek &
Ewald Georg von Kleist
First Capacitor
Timeline and Pioneers
 1752 AD
Benjamin Franklin
between lightning and electricity
Establishes
 1767 AD
Joseph Priestley
electrical inverse-square law
Proposes
link
 1785 AD
Charles-Augustine de Coulomb
Inverse-square law of electrostatics
 1791 AD
Luigi Galvani
Galvanic Battery
Timeline and Pioneers
 1799 AD
Battery)
Alessandro Volta Voltaic
Cell
(chemical
 1820 AD
Hans Christian Oersted Compass needle
deflects when a battery nearby is switched on and off
 1820 AD
Andre Marie Ampere
Coil of
carrying current behaves like magnet (Solenoid)
 1826 AD
Georg Simon Ohm
electrical resistance
wire
Ohm’s Law of
Timeline and Pioneers
 1831 AD
Carl Friedrich Gauss
Law of Flux densities
Gauss’s Law or
 1831 AD
Telegraphy
Magnetism
Wilhelm Eduard Weber
 1831 AD
Michael Faraday
electromagnetic induction
Law
and
of
 1833 AD
Heinrich Friedrich Emil Lenz
Increase or decrease of magnetic flux induces
electromotive force
Timeline and Pioneers
 1835 AD
Joseph Henry
Electric relay
Self
 1837 AD
Telegraphy, Morse Code
Samuel Morse
inductance,
 1840 AD
James Prescott Joule
Joule’s
Law,
amount of heat produced in a circuit proportional to
product of time, resitance and square of current
 1854 AD
Gustav Robert Kirchoff Conservation
of
electric charge and energy (Kirchoff’s Voltage, Current
Laws)
Timeline and Pioneers
 1865 AD
James Clerk Maxwell
Maxwell’s
equations linking electricity and magnetism, Father of
electromagnetic theory
 1878 AD
light bulb
Thomas Alva Edison
Incandescent
 1888 AD
Heinrich Rudolf Hertz
Radio
wave
propagation in free space and various media,
experimental verification of Maxwell’s equations
Timeline and Pioneers
 1897 AD
electron
Joseph John Thomson
 1905 AD
Albert Einstein
& Special Theory of Relativity
Discovery
of
Speed of Light
 1911 AD
Heike Kammerlingh Onnes
Superconductivity