CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERS

It consists of cw radar and fmcw radar ,range measurement,if amplifier and fmcw altimeterThe CW radar operates using continuous wave transmission, while the FMCW radar employs frequency-modulated continuous wave technology. Range measurement is a crucial aspect of radar systems, providing information about the distance to a target. The IF amplifier plays a key role in signal processing, amplifying intermediate frequency signals for further analysis. The FMCW altimeter utilizes frequency-modulated continuous wave technology to accurately measure altitude above a reference point.

1. RADAR ENGINEERINGUnit -2
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE1

2. Radar Engineering
RADAR ENGINEERING UNIT –II
CW AND FREQUENCY MODULATED RADAR
FM-CW RADAR
S Jagadeesh
Associate Professor
Dept. of ECE
Email: [email protected]
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE2

3. Radar Engineering
COURSE OUTCOMES
At the end of this course the learners will be able to:
CO1:Model the radar range equation.
CO2:Make use of the range equation in analytical problems.
CO3:Explain the different types of radars and its applications.
CO4:Classify the different tracking techniques
CO5:Explain the performance of radar receiver systems.
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4. Radar Engineering
MAPPING OF COURSE OUTCOMES WITH PROGRAM OUTCOMES:
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CO/POPO 1PO 2PO 3PO 4PO 5PO 6PO 7PO 8PO 9PO 10PO 11PO 12
CO1 3 2 1 1 - - - - - - - -
CO2 3 2 2 1 - - - - - - - -
CO3 2 1 1 - - - - - - - - -
CO4 2 1 1 1 - - - - - - - -
CO5 2 1 1 - - - - - - - - -

5. Radar Engineering
MAPPING OF COURSE OUTCOMES WITH PROGRAM OUTCOMES:
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE5
CO/POPO 1PO 2PO 3PO 4PO 5PO 6PO 7PO 8PO 9PO 10PO 11PO 12
CO1 3 2 1 1 - - - - - - - -
CO2 3 2 2 1 - - - - - - - -
CO3 2 1 1 - - - - - - - - -
CO4 2 1 1 1 - - - - - - - -
CO5 2 1 1 - - - - - - - - -

6. Radar Engineering
MAPPING OF COURSE OUTCOMES WITH PROGRAM SPECIFIC OUTCOMES:
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CO/PSO PSO1 PSO2
CO1
3 -
CO2 3 -
CO3 2 -
CO4 2 -
CO5 2 -

7. Radar Engineering
UNIT –II
CW AND FREQUENCY MODULATED RADAR
CW
➢Doppler Effect
➢CW Radar –Block Diagram
➢Isolation betweenTransmitter and
Receiver
➢Non-zero IF Receiver
➢Receiver Bandwidth Requirements
➢Applications of CW radar
➢IllustrativeProblems.
FM-CW Radar
➢Range and Doppler Measurement
➢Block Diagram and Characteristics
➢FM-CW altimeter
➢MultipleFrequencyCWRadar
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8. Radar Engineering
DOPPLER EFFECT
➢Doppler effect implies frequency of a wave when transmitted by a
source it is not necessarily same as the frequency of the transmitted
wave when picked up by a receiver
➢The received frequency depends on relative motion between
Transmitter and Receiver
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9. Radar Engineering
DOPPLER EFFECT
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Source is Moving Destination is Moving
??????
??????>??????
??????
Source is Moving
Destination is Moving
Destination is
Stationary
Source is
Stationary
Source is Moving
Destination is
Moving
Source is Moving
Destination is
Stationary
Destination is
Moving
Source is
Stationary
??????
??????<??????
??????

10. Radar Engineering
DOPPLER EFFECT
Depending on the relative motion between the source and destination,
the change in the received frequency at the destination is known as
“Doppler Shift”
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11. Radar Engineering
DOPPLER SHIFT
Doppler shift depends up on the
relative velocity between the source
and destination
&#3627408439;&#3627408476;&#3627408477;&#3627408477;??????&#3627408466;&#3627408479;&#3627408454;ℎ??????&#3627408467;&#3627408481;(∇&#3627408467;)=
2&#3627408457;
&#3627408453;
??????
=
2&#3627408457;&#3627408438;&#3627408476;&#3627408480;??????
??????
Here,
&#3627408457;
&#3627408453;=&#3627408453;&#3627408466;????????????&#3627408481;????????????&#3627408466;??????&#3627408466;??????&#3627408476;????????????&#3627408481;??????
??????=??????&#3627408477;&#3627408466;&#3627408479;??????&#3627408481;??????&#3627408475;&#3627408468;&#3627408458;????????????&#3627408466;??????&#3627408466;&#3627408475;&#3627408468;&#3627408481;ℎ
&#3627408457;=&#3627408455;??????&#3627408479;&#3627408468;&#3627408466;&#3627408481;??????&#3627408466;??????&#3627408476;????????????&#3627408481;??????
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V
??????

12. Radar Engineering
DOPPLER SHIFT
This principle used in Doppler Radarto find the velocity of the moving
targets
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13. Radar Engineering
PROBLEM 1
Find the doppler shift caused by a
vehicle moving towards a Radar at
96 KM/h, if the radar operates at
10 GHz.
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14. Radar Engineering
PROBLEM 2
What is the doppler shift when
tracking a car moving away from
Radar at 1000 Miles/Hr. The Radar
operates at 1GHz.
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15. Radar Engineering
CWRADAR WORKING PRINCIPLE
➢Itispossibletodetectmovingtargets
byradiatingun-modulatedcontinuous
wave(CW).
➢RadarmakestheuseofDopplerShift
fortargetspeedmeasurement.
➢Note:Ifacommonantennaservesfor
bothTransmitterandReceiver,thena
“Circulator”willbeusedforthepurpose
ofisolationofbothTransmitterand
Receiver.
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE15
Frequency Response

16. Radar Engineering
CWRADAR -ADVANTAGES
➢CW Radar has no blind speeds
➢CW Radar is able to give accurate relative velocity
➢It operates at low power levels
➢It is used for small and large ranges with high degree of efficiency
➢Radar performance is not effected by stationary object
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17. Radar Engineering
CWRADAR -DISADVANTAGES
➢CW radar cannot determine the target range
➢If more number of targets are present, there is a chance of ambiguity
in measurement
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18. Radar Engineering
CWRADAR -APPLICATIONS
➢CW radar can be used in traffic counters
➢CW radar serves as a intruder alarm in security systems
➢CW radar serves in monitoring the runway of an airport
➢CW radar will be used in measuring the ball speed in sports such as Cricket.
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19. Radar Engineering
ISOLATION BETWEEN TRANSMITTER AND RECEIVER
Isolationbetweentransmitterandreceiverisanimportantaspecttobe
studiedandaddressedinsimpleCWradarswhereasingleantenna
servesthepurposeofbothtransmissionandreception.
AmoderateamountofTransmitterleakage(referencesignalfromthe
transmittertothereceiver)enteringthereceiveralongwiththeecho
signalsuppliesthereferencenecessaryforthedetectionofthedoppler
frequencyshift.
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20. Radar Engineering
ISOLATION BETWEEN TRANSMITTER AND RECEIVER
Therearetwopracticaleffectswhichlimittheamountoftransmitter
leakagepowerwhichcanbetoleratedatthereceiver.Theyare:
1.Themaximumamountofpowerthereceivercanwithstand.
2.Theamountoftransmitternoisewhichentersthereceiverfromthe
transmitter.
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21. Radar Engineering
ISOLATION BETWEEN TRANSMITTER AND RECEIVER
Example:
Thesafevalueofthereceiverpower:10milliwatt
Thetransmitterpower:1KWatt
Theminimumamountofisolationbetweenthetransmitterandreceivershould
be:__________
A.100dB
B.50dB
C.120dB
D.10dB
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22. Radar Engineering
ISOLATION BETWEEN TRANSMITTER AND RECEIVER
Example:
Thesafevalueofthereceiverpower:10milliwatt
Thetransmitterpower:1KWatt
Theminimumamountofisolationbetweenthetransmitterandreceivershould
be:__________
A.100dB
B.50dB
C.120dB
D.10dB
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE22

23. Radar Engineering
ISOLATION BETWEEN TRANSMITTER AND RECEIVER
ForalongrangeCWradartheisolationisdeterminedthenoisethat
accompaniesthetransmitterleakageratherthan,byanydamage
causedbyhighpower.
Example:foracertainlongrangeCWRadarthetransmitterleakage
poweris10mW,minimumdetectablesignalpoweris10
-13
watt.Then
whatshouldbethelimitoftransmitternoiseindB??
Ans:Below-130dB
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE23

24. Radar Engineering
IF RECEIVER
In simple CW radar receiver, the local oscillator is replaced by a transmitter leakage
signal this concept is called as “Homodyne Receiver” (Zero IF Receiver)
But these kind of receivers are very sensitive to “flicker noise”
The super heterodyne receivers (Non-zero IF receiver) are able to over come the
problem of flicker noise by using an intermediate frequency high enough to make the
flicker noise small compared with normal receiver noise
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE24

25. Radar Engineering
IF RECEIVER
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE25

26. Radar Engineering
RECEIVER BANDWIDTH REQUIREMENTS
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27. Radar Engineering
RECEIVER BANDWIDTH REQUIREMENTS
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE27

28. Radar Engineering
RECEIVER BANDWIDTH REQUIREMENTS
(SPECTRUM BROADENING OF IF AMPLIFIER)
1. The spread in the spectrum due to antenna scanning
Let an antenna beam width is : ??????
&#3627408437;
Antenna scanning rate: ??????
&#3627408454;
Then, the spread in the spectrum of the received signal : 1/
????????????
????????????
Hz
Example: Find the spread in the spectrum of the received signal if the antenna beam
width is 2
0
and antenna scanning rate is 36 degrees/sec.
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE28

29. Radar Engineering
RECEIVER BANDWIDTH REQUIREMENTS
(SPECTRUM BROADENING OF IF AMPLIFIER)
2. Target cross section fluctuations
3. Modulation of Echo due to propeller (Ex: due to propeller of helicopter)
4. Variation on target relative velocity
Let ??????
??????is the acceleration w.r.t Radar
Then, the signal will occupy a bandwidth of
????????????
??????=
&#3627409360;????????????
??????
&#3627409359;/&#3627409360;
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE29

30. Radar Engineering
RECEIVER BANDWIDTH REQUIREMENTS
(SPECTRUM BROADENING OF IF AMPLIFIER)
Example: find the doppler signal bandwidth if a target acceleration is due to gravity
and the operating wavelength is 10 CM.
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE30
????????????
??????=
&#3627409360; ??????
??????
??????
&#3627409359;/&#3627409360;

31. Radar Engineering
RECEIVER BANDWIDTH REQUIREMENTS
(SPECTRUM BROADENING OF IF AMPLIFIER)
To improve the efficiency and reduce the effect of noise, the filter banks are used
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32. Radar Engineering
FREQUENCY MODULATED CW(FM-CW) RADAR
Thesystemtransmitsacontinuouswaveatacertainfrequency,whichisthen
modulatedoveraperiodoftimeT.Thisgivesthetransmittedsignala“time
stamp".Thesignaltravelsthentothetargetandpartofitisreflectedback.
Theradarwilldetectthereflectedsignalandcompareittotheoriginalone
bymixingthemandprocessingtheresultingsignal.Asimplifiedschematicis
presentedhere
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE32
Courtesy of Renesas Electronics

33. Radar Engineering
FM-CWRADAR WORKING PRINCIPLE
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE33
Courtesy of Renesas Electronics

34. Radar Engineering
RANGE MEASUREMENT
Inthefrequency-modulatedCWradar(abbreviatedFM-CW),the
transmitterfrequencyischangedasafunctionoftimeinaknown
manner.Assumethatthetransmitterfrequencyincreaseslinearlywith
time.Ifthereisnodopplershift(incaseofstationarytarget)thebeat
frequencyisameasureofthetarget’srange.
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35. Radar Engineering
RANGE MEASUREMENT
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36. Radar Engineering
DOPPLER MEASUREMENT
ADopplerfrequencyshiftwillbesuperimposedontheFMrangebeat
noteandanerroneousrangemeasurementresults.TheDoppler
frequencyshiftcausesthefrequency-timeplotoftheechosignaltobe
shiftedupordown.Ononeportionofthefrequency-modulationcycle
thebeatfrequencyisincreasedbytheDopplershift,whileontheother
portion,itisdecreased.
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37. Radar Engineering
DOPPLER MEASUREMENT
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38. Radar Engineering
FM-CWRADAR BLOCK DIAGRAM
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39. Radar Engineering
FM-CWALTIMETER
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE39
Courtesy of Mathworks

40. Radar Engineering
FM-CWALTIMETER
(USING SIDEBAND SUPER HETERODYNE RECEIVER)
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41. Radar Engineering
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE41
Courtesy of Mathworks

42. Radar Engineering
MULTIPLE FREQUENCY CW RADAR
▪The Transmitted signal sin2??????&#3627408467;
0&#3627408481;
▪Received Echo Signal sin2??????&#3627408467;
0(&#3627408481;−&#3627408455;)
▪In a phase detector,
▪∇∅=2??????&#3627408467;
0&#3627408455;⇒2??????&#3627408467;
0
2&#3627408453;
&#3627408438;
=
4????????????0&#3627408453;
&#3627408438;
▪Therefore,
▪??????=
????????????∅
??????????????????&#3627409358;
=
??????
????????????
??????∅
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE42
▪When the maximum phase difference ??????∅=2??????
▪The maximum range is &#3627408453;
??????????????????=
??????
4??????
2??????=
??????
2
▪Hence the maximum range depends on radar operating
wave length, and its limited and very small in case of
lower operating wavelengths.
▪Hence in a a multiple frequency radar with frequencies
&#3627408467;
1,&#3627408467;
2
▪The range, ??????=
????????????∅
????????????(??????&#3627409359;−??????&#3627409360;)
⇒??????
??????????????????=
??????
&#3627409360;(??????&#3627409359;−??????&#3627409360;)
.
▪Here the maximum radar range depends on the
difference between the frequencies of operation.

43. Radar Engineering
SUMMARY OF RADAR SYSTEMS
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44. Radar Engineering
PREVIOUS YEAR QUESTION PAPERS
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AR20 Aug 2023
Supply

45. Radar Engineering
PREVIOUS YEAR QUESTION PAPERS
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE45
AR20 June 2023
Regular

46. Radar Engineering
PREVIOUS YEAR QUESTION PAPERS
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE46
AR 19June 2023
Supply

47. Radar Engineering
PREVIOUS YEAR QUESTION PAPERS
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE47
AR 19 Aug 2022
Supply

48. Radar Engineering
PREVIOUS YEAR QUESTION PAPERS
24-02-2024 DEPT. OF ECE, ADITYA ENGINEERING COLLEGE48
AR 19 June 2022
Regular

49. Radar Engineering
EXTERNAL LINKS FOR UNDERSTANDING OF
CRITICAL CONCEPTS
FMCWRadarApplicationsinautomobiles(MatlabTech Talks)
https://www.youtube.com/watch?v=-N7A5CIi0sg&t=3s
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50. Radar Engineering
THANK YOU…
All the Best for Sessional and End Semester Examinations…
S Jagadeesh,
Associate Professor
Dept. of Electronics and Communication Engineering
Aditya Engineering College(A)
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