MICROWAVE PASSIVE COMPONENTS BY E.GANGADURAI

1. UNIT III MIROWAVE PASSIVE COMPONENTS
CONTENTS:
Microwave frequency range, significance of microwave
frequency range - applications of microwaves.
Scattering matrix -Concept of N port scattering matrix
representation- Properties of S matrix- S matrix
formulation of two-port junction. Microwave junctions
- Tee junctions –Magic Tee - Rat race - Corners - bends
and twists - Directional couplers - two hole directional
couplers- Ferrites - important microwave properties
and applications – Termination - Gyrator- Isolator-
Circulator - Attenuator - Phase changer – S Matrix for
microwave components – Cylindrical cavity resonators.

2. MICROWAVE FREQUENCY RANGE
Microwaves are a form of electromagnetic radiation with wavelengths
ranging from as long as one meter to as short as one millimeter; with
frequencies between 300 MHz (100 cm) and 300 GHz (0.1 cm). This broad
definition includes both UHF and EHF (millimeter waves), and various
sources use different boundaries.

3. FREQUENCY BAND DESIGNATION
FREQUENCY
BAND
DESIGNATION TYPICAL SERVICE
330kHz Very low frequency (VLF) Navigation, sonar
30300 kHz Low frequency (LF) Radio beacons, navigational aids
3003,000kHz Medium frequency (MF) AM broadcasting, maritime radio, Coast Guard
communication, direction finding
330MHz High frequency (HF) Telephone, telegraph, and facsimile; shortwave international
broadcasting; armature radio; citizen's band; ship to coast
and Ship to aircraft communication
30300MHz Very high frequency
(VHF)
Television, FM broadcast, air traffic control, police, taxicab
Mobil radio, navigational aids
3003,000MHz Ultrahigh frequency
(UHF)
Television, satellite communication, radiosonde, surveillance
radar, navigational aids
330GHz Super high frequency
(SHF)
Airborne radar, microwave links, common carrier land mobile
communication, satellite communication
30300GHz Extreme high frequency
(EHF) Radar, experimental

4. MICROWAVE FREQUENCY BAND DESIGNATION
FREQUENCY OLD BAND DESIGNATION NEW BAND DESIGNATION
500-1000MHz VHF C
1-2GHz L D
2-3GHz S E
3-4GHz S F
4-6GHz C G
6-8GHz C H
8-10GHz X I
10-12.4GHz X J
12.4-18GHz Ku J
18-20GHz K J
20-26.5GHz K K
26.5-40GHz Ka K

5. APPLICATIONS OF MICROWAVES
• Antenna gain is proportional to the electrical size of the antenna. At higher frequencies,
more antenna gain is therefore possible for a given physical antenna size, which has
important consequences for implementing miniaturized microwave systems.
• More bandwidth can be realized at higher frequencies. Bandwidth is critically important
because available frequency bands in the electromagnetic spectrum are being rapidly
depleted.
• Microwave signals travel by line of sight are not bent by the ionosphere as are lower
frequency signals and thus satellite and terrestrial communication links with very high
capacities are possible.
• Effective reflection area (radar cross section) of a radar target is proportional to the
target’s electrical size. Thus generally microwave frequencies are preferred for radar
systems.

6. APPLICATIONS OF MICROWAVES
• Various molecular, atomic, and nuclear resonances occur at microwave frequencies, creating
a variety of unique applications in the areas of basic science, remote sensing, medical
diagnostics and treatment, and heating methods.
• Today, the majority of applications of microwaves are related to radar and communication
systems. Radar systems are used for detecting and locating targets and for air traffic control
systems, missile tracking radars, automobile collision avoidance systems, weather prediction,
motion detectors, and a wide variety of remote sensing systems.
• Microwave communication systems handle a large fraction of the world’s international and
other long haul telephone, data and television transmissions.
• Most of the currently developing wireless telecommunications systems, such as direct
broadcast satellite (DBS) television, personal communication systems (PCSs), wireless local
area networks (WLANS), cellular video (CV) systems, and global positioning satellite (GPS)
systems rely heavily on microwave technology.
• MICROWAVE RADAR SYSTEMS(Duplexer. pulsed radar, Doppler effect)
• MICROWAVE COMMUNICATION SYSTEMS(Terrestrial systems, LOS, heterodyne
repeater, Satellite communication systems)
• INDUSTRIAL APPLICATION OF MICROWAVES(Microwave Heating-oven, Medical
applications-Diathermy, Hyperthermia, Thickness measurement, Moisture measurement in
solid material)

7. SCATTERING MATRIX
• A set of linear equations can be written to describe the
network in terms of injected and transmitted power waves
2221212
2121111
aSaSb
aSaSb


2
1
2221
1211
2
1
a
a
SS
SS
b
b

jportatinjectedPower
iportatmeasuredPower
a
b
S
j
i
ij 
Sii = the ratio of the reflected power to the injected power at port i
Sij = the ratio of the power measured at port j to the power injected at port i

8. Concept of N port scattering matrix representation

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
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N
3
2
1
NN2N1N
...
N23231
N32221
N11211
bN
b
b
a
...
a
a
a
s.....ss
..........
s.....ss
s.....ss
s.....ss
.
.
2
1

9. MICROWAVE SETUP

10. MICROWAVE PASSIVE COMPONENTS
1.REFLEX CLYSTRON

11. 2.ISOLATOR 3.MAGIC TEE
4.E-PLANE TEE
5.H-PLANE TEE
6.CIRCULATOR
7.FREQUENCY METER

12. 8.VARIABLE
ATTENUATOR
9.L BEND
10.MATCHED
TERMINATOR
11.RAT-RACE(HYBRID RING)
12.SLOTTED LINE

13. 13.PHASE SHIFTER 14.TWIST
15.TUNER
16.MULTI HOLE DIRECTIONAL COUPULER

14. MICROWAVE ANTENNAS
1.SPIRAL ANTENNA
2.PARABOLIC ANTENNA
3.MIROSTIPE ANTENNA(PATCH
ANTENNA)
4.HORN ANTENNAS

15. REFLEX KLYSTRON

16. Magnetron

17. TRAVELLING WAVE TUBE

20. RADIATION PATTERN
CYLINDRICAL RESONANT CAVITY

21. 
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
0
0
0
3231
2321
1312
SS
SS
SS
S

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


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



331313
131112
131211
SSS
SSS
SSS
S
S-MATRIX FOR MICROWAVE –T JOINT
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
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
0
0
0
3231
2321
1312
SS
SS
SS
S

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
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



331313
131112
131211
SSS
SSS
SSS
S
S-MATRIX FOR MICROWAVE –H JOINT
2313 SS 

22. 
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
00
00
00
00
4241
3231
2423
1413
SS
SS
SS
SS
S
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
00
00
00
00
4341
3432
2321
1412
SS
SS
SS
SS
S
S MATRIX FOR MAGIC T
HYBRID RING(RAT RACE CIRCUIT)

23. dBPP )/(log10 4110Coupling Factor(dB)
dBPP )/(log10 4110Directivity (dB)
P1- power input to port1
P3-power output from port 3
P4-power output from port 4
S-matrix of Directional coupler

24. 
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
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
00
00
00
00
4341
3432
2321
1412
SS
SS
SS
SS
S
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

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





00
00
00
00
pjq
pjq
jqp
jqp
S
S-matrix of Directional coupler

25. REFERENCES:
1. Samuel Y Liao, “Microwave Devices &
Circuits” , Prentice Hall of India, 2006
2. Annapurna Das and Sisir K Das, “Microwave
Engineering”, Tata McGrawHill Inc., 2004.