Applied ElectromagneticsApplied Electromagnetics

Course Name: Applied Electromagnetics

Course Code: COMP 3047

Professor: Ali Abdulsattar Hussein

ahussein@georgebrown caahussein@georgebrown.ca

Course Outline

Please refer to the PDF document AppliedEM CourseOutlinePlease refer to the PDF document AppliedEM_CourseOutline.

TextbookTextbook

• Roy Blake, Wireless Technology Fundamentals (Customized Book For COMP 3047) Delmar Thomson Learning ISBN 0 1764 3933 13047), Delmar - Thomson Learning, ISBN 0-1764-3933-1.

Other References

R Bl k El t i C i ti S t 2nd Editi D l Th• Roy Blake, Electronic Communication Systems, 2nd Edition, Delmar - Thomson Learning, 2002, ISBN 0-7668-2684-8.

• Constantine A. Balanis, Antenna Theory (Analysis and Design), 2nd Edition, 1997, J h Wil & S ISBN 0 471 59268 4John Wiley & Sons, ISBN 0-471-59268-4.

• Matthew M. Radmanesh, Radio Frequency and Microwave Electronics, 2001, Prentice-Hall, ISBN 0-027958-7.

E l i P dEvaluation Procedure

Activity Mark Notes

Quizzes and A i t 20% Failure to submit an assignment after 7 days from the

d d t ill lt i k fAssignments 20% due date will result in a mark of zero

Midterm Exam 25% The midterm exam will de done on the seventh week of the course

Final Exam 25% The final exam will be done on the last week of the course

Lab 30%Lab 30%

Total 100% A final mark of at least 50% must be achieved in order to pass the course

Course Topics

• Basics of Signals and Communication Systems … Wk. 1

• Electromagnetic Waves and Propagation Wk 2• Electromagnetic Waves and Propagation … Wk. 2

• Transmission Line … Wks. 3 & 4

• Antenna Parameters Basic Antennas and Phased Arrays Wks 5 & 6• Antenna Parameters, Basic Antennas and Phased Arrays … Wks. 5 & 6

• Midterm Exam … Wk. 7

C ll l PCS d Oth Ki d f P t bl A t Wk 8• Cellular, PCS and Other Kinds of Portable Antennas … Wk. 8

• Microwave Devices … Wk. 9

VHF UHF d S t llit P ti Wk 10 & 11• VHF, UHF and Satellite Propagation … Wks. 10 & 11

• Cellular Radio … Wks. 12 & 13

• Final Exam … Wk. 14

Basic Components ofa Communication System

• The basic objective of any communication system is to transfer information from a source to a destination.

• Information can be analog, such as audio and video signals, or digital, such as a digital stream of data taken from a computer.

Sinusoidal Signals

• Figure below shows a sine wave voltage signal as a function of time.

• The sine wave is an example of a periodic signal A periodic signal repeats its• The sine wave is an example of a periodic signal. A periodic signal repeats its pattern after a regular period of time (T).

• is the peak value the instantaneous voltage v(t).pV

T : Period of v(t)

: Peak value of v(t)pV : Peak value of v(t)p

• In the frequency domain the sine wave is represented by a single frequency component, as depicted in figure below.

• The frequency of the sine wave is the reciprocal of its period (T):)( οf

Hzf 1=

• The angular frequency is related to through the relation:

HzT

fο

οω οf

sradf /2 οο πω =

• A sine wave voltage signal with phase shift can be expressed in the time domain as:

θ

where;

)sin()( θωο −= tVtv p

T2TTdπθ 2

=

f ( ): Peak-to peak value of v(t)ppV

Frequency Spectrum of Periodic Signals

• According to the Fourier series any periodic signal can be decomposed into the following components:

a dc componenta fundamental frequency componentharmonic frequency components

• The dc component represents the average value of the signal over one period.p p g g p

• The fundamental component has frequency equal to the reciprocal of one period of the signal.

• The frequency of each harmonic component equal to an integer multiple times the frequency of the fundamental component.

• According to the amplitude phase form of the Fourier series a periodic voltage• According to the amplitude-phase form of the Fourier series, a periodic voltage signal v(t) can be expressed as:

∑∞

++= )sin()( kkdc tkVVtv θωο∑=1

)()(k

kkdc ο

Examplep

Figure below shows a train of pulses voltage signal with a fundamental frequency of 1 kHz.

The Fourier series of this signal is given by:

...)7sin(71)5sin(

51)3sin(

31)sin(

4)( +++++= tttttv οοοο ωωωωπ

The resulted discrete spectrum of this signal is shown in figure below.

Non-Periodic Signals

• Signals holding useful information such as audio, video and digital data are non-periodic.

• The spectrum of a non-periodic signal is a continuous function of frequency as explained in figure below.

• Different types of information signals occupy different ranges of frequenciesDifferent types of information signals occupy different ranges of frequencies.

T f Si l B d idth f F iType of Signal Bandwidth of FrequenciesTelephone-quality signal 300 Hz – 3 kHzHigh-fidelity music signal 20 Hz – 20 kHzTelevision-broadcast quality signal 0 Hz – 4.2 MHzDigital data stream Depends on the bit rate

• The range of frequencies of an information signal is called the baseband.

• In communication systems, base-band signals are modulated over high-frequency carriers for radio-frequency (RF) transmission.

Radio Spectrump

Range of Frequencies Band Wavelengthg q g30 Hz - 300 Hz Extremely Low Frequencies ELF300 Hz - 3 kHz Voice Frequencies VF3 kHz 30 kHz Very Low Frequencies VLF 100 km 10 km3 kHz - 30 kHz Very Low Frequencies VLF 100 km - 10 km30 kHz - 300 kHz Low Frequencies LF 10 km - 1 km300 KHz - 3 MHz Medium Frequencies MF 1 km - 100 m3 MHz - 30 MHz High Frequencies HF 100 m - 10 m30 MHz - 300 MHz Very High Frequencies VHF 10 m – 1 m300 MHz - 3 GHz Ultra High Frequencies UHF 1 m – 10 cmg q3 GHz - 30 GHz Super High Frequencies SHF 10 cm – 1 cm30 GHz - 300 GHz Extremely High Frequencies EHF 1 cm – 1 mm

Noise in Communication Systems

• Noise is a random undesirable signal that affects the quality of information g q ybeing transmitted in a communication system.

• The transmitter, receiver and communication channel all contribute to adding noise to the transmitted signal.

• The communication equipment contribute to internal noise resources.

• The communication channel contributes to external noise resources.

Noise ResourcesNoise Resources

• Equipment Noise: automobile engines and electric motors with brushesq p g

• Atmospheric Noise: lightning

• Space Noise: sun

• Thermal Noise: random motion of electrons in conductors due to heat

• Shot Noise: random variations in current flow in active devices

• Partition Noise: a single current in a BJT separates between two paths

• Flicker Noise: 1/f noiseFlicker Noise: 1/f noise

Amplitude Modulation

• AM is an analog modulation method used to modulate a base-band signal over a g ghigh-frequency carrier for RF transmission.

• In AM modulation, the instantaneous amplitude of a sine wave carrier is changed proportionally with the message signal.

Message Signal Carrier

AM Signal

• An AM voltage signal can be represented as in the following expression:• An AM voltage signal can be represented as in the following expression:

[ ] )sin()(1)( ttmvAtv ω+

Where;

[ ] )sin()(1)( ttmvAtv cmAM ω+=

:)(:)(

tvtv AM AM signal (Modulated Signal)

Message signal (Modulating Signal)

::

:)(m

tv

c

m

ω

Message signal (Modulating Signal)

Modulation index

Angular frequency of the carrier:A

g q y

Peak value of the carrier before modulation

• AM yields shifting the base-band frequency spectrum of the message signal to the carrier frequency Upper and lower half bands are produced around the carriercarrier frequency. Upper and lower half bands are produced around the carrier frequency in addition to the carrier frequency component itself.

• The transmission bandwidth of an AM signal is double the bandwidth of the )( TBe t a s ss o ba d dt o a s g a s doub e t e ba d dt o t ebase-band signal (B).

)( T

Spectrum of a base-band signal

Spectrum of an AM signal

Frequency Modulation

• FM is an analog modulation method in which the frequency of a sine wave carrier g q yis changed proportional to the message signal.

• FM requires a wider transmission bandwidth as compared to AM. However, FM results in a better immunity against noise effect as compared to AM.

Message Signal Carrier

FM Signal

P l A li d M d l iPulse Amplitude Modulationand the Nyquist Rate

• A PAM signal consists of a train of pulses. The amplitude of those pulses is made proportional to the message signalproportional to the message signal.

• A PAM signal represents samples of the original message signal.

Message Signal

PAM SignalPAM Signal

• According to the sampling theory if an analog signal is sampled at a rate which is at least twice the highest frequency component contained in the analog signalis at least twice the highest frequency component contained in the analog signal, the original analog signal can be recovered by lowpass filtering the signal of samples.

• The theoretical minimum sampling rate, which is twice the baseband bandwidth of the message signal, is called the Nyquist rate.

BfBf

s

s

22

=≥Sampling rate

Nyquist rate f syq

Pulse Modulation Methods

Figure:

a. Modulating (message) signal(sine wave).

b. Pulse amplitude modulatione(PAM).

c. Pulse width modulation (PWM).

d. Pulse position modulation (PPM).p ( )

Pulse-Code Modulation

• In PCM the samples of an analog signal are coded into words of binary digits (bits). Each word consists of a number of bits, and it represents the value of a sample taken from the original analog signal.

Sample and PCMAnalog LPF Sample and Hold Circuit Coder PCM

SignalAnalog Signal

----------- ADC ----------

S O OriginalPCM

SignalDecoder Sero-Order

Hold Circuit LPFOriginal Analog Signal

DAC----------- DAC ----------

Pulse-Code Modulation

Figure: Sample and hold. 4-bit PCM.

Pulse-Code Modulation

Figure:

a. Samples of a signal (PAM signal).

b. Sample and hold plus quantization.p p qAllowing sufficient conversion time.The quantized levels allowrepresenting the samples byp g p ynumeric values.

c. Coding of the quantized samples.g q p