Course Structure 2
Theory: 80
Chapter 1: Introduction 8 marks
Chapter 2: RF and M/W Transmission Lines 10 marks
Chapter 3: RF and M/W Network Theory and Analysis 8 marks
Chapter 4: RF/MW Components and Devices 10 marks
Chapter 5: Microwave Generator 8 marks
Chapter 6: RF Design Practice 20 marks
Chapter 7: Microwave Antennas and Propagation 8 marks
Chapter 8: RF/MW Measurements 8 marks
Practical: 25
Reference Books 3
1. Microwave Electronics- K.C Gupta, Tata McGraw Hill
2. Microwave Engineering- A.K. Gautam, S.K.Kataria & Sons
3. Microwave Techniques-D.C. Agrawal, Tata Mc Graw-hill
4. Microwave Devices and Circuits-Samuel Y. Liao, PHI 3rd Edition,1994
5. Microwave Engineering-David M. Pozar, 2nd Edition, Newington CT:
1997
6. Engineering Electromagnetic-W.H. Hyatt, McGraw-Hill Book
Company
7. Electronic Transmission Technology: Lines, Waves and Antennas-
William Sinnema, Prentice Hall
Chapter 1:
Introduction
PRESENTED BY:
ER. KOBID KARKEE
RF/Microwave 5
RF is a rate of oscillation in the range around 3KHz to
300MHz, which corresponds to the frequency of radio
waves and the alternating currents which carry radio
signals.
Microwave: is not meant to suggest a wavelength
micrometer, have smaller wavelength compared to radio
broadcasting.
Frequency Range: 300MHz-300GHz
Wavelength: 1mm – 1m
Includes UHF (0.3-3GHz), SHF (3-30GHz) and EHF (30-
300GHz) signals.
History of Microwave 6
James Clerk Maxwell (1831-1879)
Unified all previous known results, experimental and theoretical
on electromagnetic waves in four equations.
Predicted the existence of EM waves.
Heinrich Rudolf Hertz (1857-1937)
Experimentally confirmed Maxwell’s prediction.
Guglielmo Marconi (1874-1937)
Transmitted information on an experimental basis at microwave
frequencies.
George C. Southworth (1930)
Really carried out Marconi’s experiments on a commercial basis.
During World War II (1945)
Radar was invented and was exploited for military applications.
Electromagnetic Spectrum 7
Electromagnetic Spectrum 8
Electromagnetic Spectrum 9
10
IEEE Microwave Frequency Band 11
Microwave System 12
Microwave Sources 13
High power microwave sources use specialized vacuum
tubes to generate microwave.
Operate on the principle of ballistic motion of electrons
in a vacuum under the influence of controlling electric
or magnetic field.
Includes magnetron, klystron, travelling wave tube
(TWT) and gyrotron.
These devices work in the density modulated mode.
(work on the basis of clumps of electrons flying
ballistically through them, rather than using a
continuous stream of electrons).
14
Lower power microwave sources use solid state
devices such as the FET, tunnel diodes, Gunn diodes
and IMPATT diodes.
MASER is a solid state device which amplifies
microwave using similar principle to the LASER, which
amplifies higher frequency light waves.
Advantages of using higher frequency 15
Larger instantaneous bandwidth for much information
Higher resolution for radar imaging and sensing
Reduced dimensions for components
Less interference by near by application
Higher speed for digital communication, signal
processing and transmission
Less crowded spectrum
Difficulty in jamming (military application)
Disadvantages of using high frequency 16
More expensive component
Higher atmospheric loss
Reliance in GaAs technology rather than Si technology
Higher component losses, lower output power from
active devices
Less accurate design tools, less mature tools
Microwave Applications 17
Communication
Before the advent of fiber-optic transmission, most long-
distance telephone calls were carried via networks of
microwave radio relay links using FDM.
Wireless LAN protocols, such as Bluetooth and the IEEE
802.11 specifications, also use microwaves in the 2.4 GHz
ISM band.
Wireless internet access IEEE 802.11a uses microwaves at
3.5-4 GHz range.
Mobile phone networks, like GSM, use the low-
microwave/high-UHF frequencies around 1.8 and 1.9 GHz
in the Americas and elsewhere, respectively.
Microwave Applications 18
Communication
3G and 4G technologies also use microwave frequencies.
(What are the bands???)
Metropolitan area network (MAN) protocols, such as
WiMAX (Worldwide Interoperability for Microwave Access)
are based on standards such as IEEE 802.16, designed to
operate between 2 to 11 GHz.
Mobile Broadband Wireless Access (MBWA) protocols
based on standards specifications such as IEEE 802.20
operate between 1.6 and 2.3 GHz.
Microwave Applications 19
Communication
Most satellite communications systems operate in the
C, X, Ka, or Ku bands of the microwave spectrum.
Satellite TV either operates in the C band for the
traditional large dish fixed satellite service or Ku band
for direct-broadcast satellite.
Military communications run primarily over X or Ku-
band links.
Microwave Applications 20
Commercial Applications
Commercial implementations are in the 2.3 GHz, 2.5 GHz,
3.5 GHz and 5.8 GHz ranges (ISM band- Industry, Science
and Medicine band).
Navigation
Global Navigation Satellite Systems (GNSS) broadcast
navigational signals in various bands between about 1.2
GHz and 1.6 GHz.
These include the Chinese Beidou, the American Global
Positioning System (GPS), the European Galileo and the
Russian GLONASS.
Microwave Applications 21
RADAR
Radar uses microwave radiation to detect the range,
speed, and other characteristics of remote objects.
Weather prediction
Geological survey for natural resource exploration.
Air traffic control, road traffic surveillance.
Microwave Applications 22
Radio astronomy
Celestial body research.
Distance measurement.
Heating and Power Application
A microwave oven uses microwave radiation at a
frequency near 2.45 GHz.
Dielectric heating through energy absorption.
Microwave heating is used in industrial processes for
drying and curing products.
Microwave Applications 23
Security
RFID based identification system.
Motion detectors.
Medical Use
Photoacoustic imaging (ultrasound).
CT scan, X-rays, MRI like imaging.
Thermo-therapy, LASER therapy.
Cancer treatment.
Behavior of circuits at conventional and
RF/Microwave bands 24
Resistor
25
26
Inductor
27
28
Capacitors 29
30
31
At microwave frequencies
everything is combination of R, L
and C.
Behavior of Circuits at Conventional 32
and RF/Microwave Bands
Low Frequency/ Conventional RF/Microwaves
Bandwidths are limited hence small no. Provide large bandwidth so its possible
of channels can be adjusted. to adjust large no. of channels.
It uses lumped element circuit theory. It uses distributed circuit theory
(ohm/m, H/m, F/m).
Current flow and voltage drops are Scattering phenomena like absorption,
used to calculate power. reflection, refraction, etc. are used in
power calculation.
Optical fibers, waveguides, strip lines,
Open wire, twisted cables, co-axial micro-strip lines are common
cables are used as transmission lines. transmission lines.
Behavior of Circuits at Conventional 33
and RF/Microwave Bands
Low Frequency/ Conventional RF/Microwaves
Lumped circuit elements are used such Cavity resonators or resonant lines are
as resistors, filters, oscillators, etc. used as oscillators, resonators, etc.
It uses current modulated mode. Density modulation or velocity
modulation are used using magnetrons,
klystrons, TWTs, etc.
Vacuum tube like devices, micro-
Almost all the solid state devices can be miniaturised solid state devices like
used. Gunn diodes, tunnel diodes, IMPITT,
TRAPPIT, etc. are used.
It can handle low power. It can handle higher power.
Assignment #1: 34
1. Mention the microwave frequency band specified by IEEE. What
are the advantages and disadvantages of using microwave signal?
2. Define microwave signal? Explain the characteristics behavior of
passive component at microwave frequency.
3. Compare and contrast the circuit behavior in conventional low
frequency and RF/Microwave frequency band. What are the
application areas of microwave system?
4. Explain the general microwave system with clear diagram.
Explain the characteristics of microwave signal.
5. Differentiate between microwave and acoustic/seismic waves.
Due Date: 1 week from the slide presentation
Thank You
ANY QUERIES???
