Electromagnetism waves fields telecommunications electrical

1. Electromagnetic wave and
Transmission line
INTRODUCTION
Bewnet G

2. It is a subject Which has been fascinating human beings for many centuries.
• In ancient days people used to asked questions like
 Why stars twinkling while planets do not?
 why there is lightning?
 Why magnetic needle deflect When it is putted in the environment?
 How light reach the earth from the sun Where there is no medium in
between?

3. • In modern days people also try to investigate issues like
 How radio stations operated?
 How Tv reception occurred?
 How do the mobile phone works?
 Why Tv reception is good in some parts of the house and not at other places?
 Why radio transmission in medium wave does not fluctuate with time whereas short wave
radio transmission does?
• All these phenomenon involves electromagnetism and almost all modern
gadgets works with the principle of electromagnetism.

4. Electromagnetic Energy Is Everywhere

5. EM phenomena
1. Low frequency high power
- Electrical machines, transformers, power generation, transmission and
distribution of electric energy.
2. High frequency low power
- Mobile communication, radar, satellite comm, optical fiber comm
• In this course we are going to develop the principles of electromagnetism
and investigate how time varying EM wave behaves.

6. E = electric field intensity
D = electric displacement(electric field density)
H = magnetic field intensity
B = magnetic flux density
= charge density
j = current density
0 (permeability of free space) = 4 x10-7
0 (permittivity of free space) = 8.854 x 10-12
c (speed of light) = 2.99792458 x 108 m/s
Maxwell’s equations
In general EM phenomena is governed by the following
four Maxwell’s equations
Relate Electric and Magnetic fields generated by charge
and current distributions.
- del(vector differential operator)
-Dot product
-Cross product
You, as a student, are not expected to memorize them , you are expected to
know them! The intellectual and even the visceral understanding of these
equations is what this course and much of electrical and computer engineering
is about.
constitutive relations

7. coaxial cable
Optical
fiber
Electromagnetic
spectrum
High frequency – high bandwidth

8. Electromagnetic Spectrum
no input
Demand
Assignment
 Spectrum as a natural resource:
 equally available in every country;
 unlike the other resources can travel across national boundaries;
 cannot be destructed, but it can be abused;
 is a limited resource.
 Supports:
 National & international communications including:
 National defense , public safety, PCs,
 Aeronautical & maritime communications,
 Navigation, Broadcasting,
 Business, & Industrial communications, etc..
 How?
by means of an effective & efficient management and monitoring
system.

9. Applications of Electromagnetic phenomena
• Renewable energy and energy conversion
• Electric power generation, transmission and distribution systems
• Transmission lines and HF circuits
• Antenna
• Satellite communication
• Fiber optic communication
• Cellular wireless communication
• Radar

10. Twisted pair cable
-Telephone line
-Low data rate
-High EMI
-Lossy at high frequency
coaxial cable
-LAN
-data rate few Mbps
-low EMI
-Moderate Loss
-Large bandwidth
waveguide
-Low bandwidth
-Low Loss at high frequency
Transmission media

11. Antenna
• Omnidirectional
vs directional
• Resonant vs non
resonant
• Wire type vs
aperture type
• Size of antennas
• Smart antennas
• Array antenna
Antenna Pattern
3D radiation
pattern
Graphically editable
Horizontal pattern
Graphically editable
Vertical pattern
Antenna
Specification
Fill mode Mesh mode

14. Satellite communication
* Large bandwidth L-band - (1-2GHz) K –band – (12-18GHz)
* Long distance S-band – (2-4GHz) ku-band – (18-27GHz)
* longer delay C-band – (4-8GHz) ka-band – (27-40GHz)
* Mobility x-band – (8-12GHz)

15. Fiber optic communication
Propagation of light through optical fiber cable
Total internal reflection
Bending
Light sources LASER , LED
Consider a ray traveling from a medium of high index to one of
low index:
And no light penetrates the second medium at all – all of the
light must be reflected.
This is called the ‘critical angle’ at or above which incident light
will be totally reflected. This is the way that optical fibers
contain light.

16. Wireless and mobile communication
• Require various aspects of EM principles
• Cellular communication Base station , users, cell
• Multipath propagation (reflection, diffraction, scattering )
• Depending on the length of travel the wave will have either constructive or destructive
interference
• As the user moves the strength of the wave varies as a function of time. This phenomena
is called fading.
• Co channel interference

17. Typical propagation environnements
macro cell
Fig 3.1 Typical propagation
environnements

18. To design and install successful and feasible wireless link properly developed propagation
model is highly required. To develop propagation model of the complex EM environment
electromagnetic principles are employed.

19. Propagation Model
HATA model parameter
justification
ITU-R P.1546 model
parameter justification
Fresnel
zone
Loss
component
s
Path
profile

20. RADAR
• Detection and measurement
• Long range detection of targets
• Clutter
• Radar resolution
Transmitter Receiver
Modulat
or
Mast
er
clock
Signal
processo
r
(comput
er)
Duplexe
r
Waveguid
e
Targe
t
Antenn
a
PPI Display of Heavy Rain

21. EMI/EMC
• How to avoid harmful interference
• Mitigation of EMI (filtering, grounding, shielding)
• Electromagnetic compatibility of devices and
environment
• IOT and 5G
• Policy, standard, regulations, laws
• Monitoring and control

22. Monitoring Station
Monitoring
station
Field-strength and signal
quality measurement
Direction-finding and
locating
Monitoring of radio station
characteristics
Search for interference-
faulty emission
Data
base
Occupancy
Long-term measurements for
propagation study project
Identification and location
Tests
Analysis and search for the cause
Advice
Search for, and measurement of
spurious radiation
Bandwidth
Frequency measurements
Search for unknown transmitters
Identification
Search for spurious radiation
Network planning
Broadcasting
cellular
Determination of
coverage area
Broadcasting
cellular

23. Smart grid control systems Deliver power more reliably and efficiently
while remaining environmentally friendly,
economical, and safe.
Ship
Service
Power
Main Power
Distribution
Propulsion
Motor
Motor
Drive
Generator
Prime
Mover
Power
Conversion
Module